AudioCircle
Industry Circles => ModWright Instruments (MWI) => Topic started by: modwright on 2 Apr 2018, 11:18 pm
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What do you guys think of the following, in lieu of a full tube mod to a digital source?
Tube Buffer with volume control, ideally remote control.
Two inputs: Simple system with say vinyl and digital source.
Zero gain, low output imepdance for matching with any SS or tube amp.
Low Noise, Low distortion.
Goal: Act as a preamp/passive preamp or volume control while adding BUFFERING, which is the most important part of any preamp!
Mulitple source input and R/C volume act as preamp functions, but without unwanted complexity, circuitry and cost.
This would add tube tone to any system, SS or otherwise.
It would improve the sound of less than stellar digital sources.
Can be used with different digital sources.
Also, being as how it is unity gain, would also integrate into a HT system without the need for a bypass.
Form factor would be medium size, one box.
Finish would be classic ModWright: Elegant, clean and sophisticated.
Cost: $995 as a starting point.
Input welcome!
Thanks,
Dan
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Hello, Dan.
I'm potentially interested in such a product. However, I'd want to compare it to a tube preamp in order to fully understand each unit's advantages and disadvantages - fortunately for me I'm relocating to the greater Vancouver, WA area soon. :thumb:
Michael
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What tubes? :scratch:
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Hi Modright,
What you just described is every thing that the Schiit Saga does at under 400 dollars....Mark Korda
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how about a line stage / preamp with a sub in/out ?
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Hi and thank you all.
Tubes: 6922
A buffer is actually all that is needed for modern digital sources, where the gain level is high enough. That is why it was suggested to me that this could be a viable product. The tube buffer allows for impedance matching with the amplifier. By adding a volume control and more than one source, it serves as a preamp.
A preamp will typically have gain and impedance matching, more controls and greater functionality overall. However, one of the most important things that a preamp does is offer a LOW output impedance. This allows for better dymamics and body to the music, as opposed to a purely passive attenuator.
Being a tube circuit of course, it also brings the magic of tubes to a system that may be pure SS otherwise.
I will take a look at what Schiit Audio is offering in this regard.
Regarding a SW in/out, what exactly did you have in mind? The ability to control the volume for the SW?
Thanks guys!
Dan
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I very much like tube based preamps/buffers with low output impedance. The iFi buffer improved dynamics with my horn speakers when placed between the passive pre and amplifies. Then I was blown away by the MicroZOTL replacing the pre/buffer. It drove 2 nominally low input impedance SS amps with no problem. Killer dynamics and transparency. Unfortunately, it's not really a preamp, and will pass dc and both my amps are direct coupled, so I don't want to chance using it.
If you can make something as transparent and uncolored as the MZ with low output impedance and a low noise floor, you're going to have something I'd want at that price point.
I appreciate that implementation will probably have more to do with how it sounds than tube selection, but I have been moving away from 6922 based preamps the past couple years, though that wouldn't stop me from trying one. Perhaps the 6sn7/12sn7 could be considered?
I demoed the Tortuga tube buffer last year and was expecting a particular sound from it based on the tubes used (6h30) and was surprised that it sounded quite the opposite of what I expected. It is a good buffer, but was not as transparent as the MZ, and was a little soft on top, though I think many people would like the softened highs.
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OK, thanks.
Dan
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"Regarding a SW in/out, what exactly did you have in mind? The ability to control the volume for the SW?"
I'd like to add a subwoofer in my 2 channel system (2.1 really).. For me, I have the Oppo205 (Modwright) and now I feel I don't need my Classe SSP800 processor except for volume control and the subwoofer.. When I listen to cd's and downloads I have it run the through 2 channel output to the Classe's 7.1 bypass where only the volume control touches the signal.. Of course no sub can be added in this configuration.. Oppo says you can't integrate the sub out from the 7.1 output with the 2 channel output.. When I watch movies, I use the HDMI, there the sub comes in.. Classe does the processing there.. If I can get a preamp with a sub then Classe is out.. (While typing this, I'm starting to think its not possible).. Only Parasound that I know of builds a preamp with a sub out.. I guess they have a built in digital crossover that can degrade the sound (????) .. I've read many wishing they can find a preamp with sub.. Maybe get some towers ?? But then I'd lose the advantage that 2 way speakers has over 3 way towers ??? ugh
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I'm not sure I understand the sub issue. A preamp/buffer with low output impedance can easily drive the full range amplifier and a pair of self powered subs, or the full range amplifier and crossover/amp for a pair of passive subs (what I use) with dual outputs on the pre/buffer.
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so how do you set the crossover between the bookshelf speakers and the sub ? do you let the bookshelf and sub overlap each other ? say between 50Hz and 120HZ region ?
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where they both can reach ?
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digital crossover between the preamp and the sub and set it at the lowest point the monitors can play ? ha, I think that's it
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so how do you set the crossover between the bookshelf speakers and the sub ? do you let the bookshelf and sub overlap each other ? say between 50Hz and 120HZ region ?
It depends on preference. I run my full range speakers full range without crossover, and just bring the subs up to meet them at about 60hz.
If you play the speakers at concert level where distortion from the 2 way woofer becomes an issue then you can high pass the 2 ways and appropriately low pass the subs via a crossover, but I personally prefer the first example and like not having an added crossover in the full range circuit.
Either way, a low output impedance pre/buffer can drive the load.
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If it looks and sounds like a Mod Wright product I am interested. I would love to see a high quality analog XO for running a 2.2 music system (stereo subs) with a variable XO point from 50 to 200 Hz (above 80 Hz calls for careful placement, Wayne Parham of Pi Speakers calls them helper subs and they are great for adding extension to speakers with restricted low end).
A single XO point could also work, but not as flexible.
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OK, thank you. I will consider adding a XO filter pole to the buffer/follower design.
Dan
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Your initial thoughts on a simple tube buffer with volume control is exactly the type of device I would be interested in. The addition of a second line out for sub woofers would be icing on the cake. :D
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Thank you for that! I have a couple of very good 6922 based tube buffer designs proven, that are very low in distortion and with exceptional bandwidth. It could easily be configured as you say. This can greatly improve any system and especially digital, without the unnecessary addition of high tube distortion and bandwidth limitation. Most sources have more than enough gain, but there should be a good buffer circuit between the volume control and amplifier input.
The best passive preamps lack this buffer stage which allows for ideal impedance matching between the volume control and amplifier input. Sonically, the lack of a buffer or active preamp stage can make things sound thin and lacking in body.
Thanks,
Dan
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I've been a fan of the Wyred 4 Sound STP-SE for a long time, which is essentially a solid state version of what you describe. Aside from its great performance and reliability, I LOVE its versatility (plenty of inputs and outputs including 12v triggers). It is also very easy to use. However, there are 3 things I really don't like about it : 1. It's ugly. It just doesn't look good in the living room. 2. It isn't the standard 17" width which is a little visually odd if you need to stack components. 3. The display is small and hard to read at 8ft + away.
If you can do (most) of what Wyred 4 Sound has done cost effectively, while fixing the issues I've stated, and swap the solid state buffer for tubes, man oh man that'd be one sweet line stage. My guess is that something like this would have to be $2000+, though. Note the Wyred is balanced, so I imagine keeping yours single ended would save a good amount of $$$.
Hope this helps give a sense of the kinds of features and conveniences I'd like to see. :thumb:
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A tube buffer is just what I'm looking for to replace my 2 yaqin buffers.
I use one for phono, and one for CD, since the yaqin's only have one input.
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Hi Guys, first of all, any buffer we do will be more expensive and higher performance than a Yaquin unit. I can't compete with Chinese mfg. cost and I won't even try. Not that there is anything wrong with these units, but I am aiming for something to perform at a higher level and will be priced at a higher level.
As to the WFS STP-SE: I am not sure that I would use a digital display. Several reasons for this, but first of all, I would rather not use a digitally controlled attennuator for this. It does appear to be a very well designed and thought out device.
I would prefer to use transformer coupling for balanced output, simply because there are numerous benefits sonicly do doing so. There is also cost however, for good quality transformers.
I will have to determine how far this design will be taken. There is a broad range between the Yaquin simple tube buffer and WFS full passive/active preamp design.
I will take all of this feedback in mind. I expect there will be a couple of models, at different price/option levels.
Thanks,
Dan
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Tell you what I would really like.... A world class buffer with not one control at all, unity gain or maybe optional gain points if desired. Single ended RCA in/out and maybe offer another balanced version if desired. Input and output, that's it.
Most of the good DAC's out there now have excellent volume control implementations, but I have yet to hear a single DAC that did not benefit from a good preamp after it. That said, and since volume controls in good DAC's are already excellent, there is a hole in the market for a really damn good buffer between DAC and amps IMO.
Sonically, it must perform perfect at low volume as well as higher volumes, with an organic artifact free midrange. Still have good bass quantity and slam, micro/macro dynamics still obvious, and keeping a full scale performance while very quiet. I wish more products performed good at low volumes. If you can turn down your system and still enjoy it, your room problems diminish greatly.
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I have a design right now that fits this bill. It is ultra low in distortion (<.03%). It offers frequency response flat from 20Hz-100Khz. Being a true buffer, it has VERY low output impedance, allowing for excellent interface with any tube or SS amp.
I agree, most DACs already offer good VC's. There are many DACs out there, that have great digital tech, but the analog stages are lacking. I have used the Pro-Ject S2 DAC ($350) as a prime example of this. By itself, the S2 DAC feeding $18K work of 150SE amp in bridge mono, driving Maggie 1.7i's in my office sounds good, but is a bit lean. I then route the same RCA out signal through the tube buffer and everything just fleshes out and sounds fantastic! I mention the fact that I am using this digital front end (DAC/Tube buffer combo) with high end amps and good speakers to illustrate the point that the source does NOT hold the overall system back!
Buffers have a bad reputation, in my opinion, of being a 'tone control', 'bandaid', or other 'additive' sonic device. Many tube buffers intentionally add tube distortion for added warmth. This can be an enjoyable sound, and can also reduce resolution, detail and overall sonics. Pleasant, but not accurate.
I have hesitated to spend the money to develop the enclosure and take the product to production, because I needed to be sure that the demand is there.
I suppose the thing to do is make a small number of prototypes and send them out for Beta feedback.
Any that are looking for what is described hear, and by paul79, please let me know!
What would you expect to pay for:
1) High quality tube buffer, with 1-2 RCA inputs and 1-2 RCA outputs.
2) Optional balanced outs via transformer coupling - add cost.
3) Including a linear power supply, 5VDC or other common voltage as required by the Pro-Ject and other DACs with external wall wart supplies.
The ideal would be a base design with optional XLR outs and optional integral LPS.
I have a design that sounds great! I just need to know that there is a demand. I also need to know what people would expect to pay for such a product, designed nicely, in a compact enclosure with good quality build, but not over-the-top and expensive enclosure.
Thank you all in advance!
Dan
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Good evening,
Dan,
My thoughts on what folks (me) might spend (my 2 cents). I have been looking to downsize over the past year and am taking a look at the ifi audio itube2, Schiit Saga(as a previous poster commented) and the Mapletree Black Buff. All three of these products sell for between, $349 and $475 (gain is also available/possible for two of them), which for me, if I am really downsizing:), would be the limit.
Personally I am looking for a single RCA input and a single RCA output and any cost savings that may be achieved could be applied elsewhere in the design, while keeping to the price point.
Mike
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Do we know approximately how much this MW tube buffer would cost?
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With power supply for the DAC and unity gain, I was thinking about $500. Fit and finish and options would effect this. It will be Hand Crafted in the U.S.A. and made with good quality parts. It will not be made in china or machine assembled.
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Being scared of sonic compromise, and that my linestage is very good, I would be willing to pay $1500-$2.5K for a really good one. Single ended RCA for my needs.
The benefit to this in my opinion, from an ultra simplistic engineering standpoint, is no extra volume control or anything mechanical mucking up the sound. I think ALL volume control implementations no matter, are a compromise, and if the DAC has a very good one already, this should be all we need.
I would be happy to try out what you have there Dan. If you want to talk, more context, let me know. I have what I believe to be a very resolving system with some of the best digital currently available.
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I really like the idea of a very high quality, simple, buffer with single input and dual outputs. No pots or switches in the signal path. Adjustable out voltage would be amazing, but perhaps too complex? This type of buffer would be GREAT for folks, like me, who have a nice DAC with high quality volume control, but need dual outputs to run amps AND subwoofers "direct" from the source. :thumb:
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I agree with you guys that it should be simple and elegant as far as the signal path goes and connectivity. Adding relays, switches, volume controls all do more to add to the signal path in ways that are not desirable.
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Hi Dan,
Is there ever a chance for you to come out with a CD player modded with a volume control? I doubt if anything could ever beat that.
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Dan if ya asked me I would want a CD player or DAC with a quality analog section of a Class "A" preamp. Then a volume control that gets out the way.
For digital only systems a no brainer. Buffers mostly suck however if you are designing it another story. I just feel why spend on a buffer buy better components like yours.
Dan why do we need an analog section in a DAC to begin with ? Cannot one design a DAC that outputs directly to a preamp after
analog conversion from DAC ?
charles
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Hi Rollo and others who have posted, and thank you.
First of all, the analog stage of a DAC/CD/DVD player does a few things:
1) If a current output DAC (common in better DACs) there needs to be a current to voltage stage (I-V) after the DAC.
2) Analog filtering needs to be present to filter out ultra high frequencies.
3) Analog stage gain.
A preamp serves several functions:
1) Input select.
2) Gain/buffer.
3) Volume control.
4)Tone controls in some, but not common these days.
5) Home theater bypass to allow integration of HT product with 2CH Stereo.
6) Possibly phase switching.
7) Possibly balance L/R control.
Today's DACs typically put out 2Vrms analog level in stock form. Most amps reach full power at 1V-1.5Vrms, unless a low gain tube amp or other unique designs. Pass's First Watt designs are necessarily low gain and there are some others that really do want additional gain.
So, a good DAC or player with a good (lossless) volume control and 2Vrms+ of output voltage, can drive an amp directly.
Why add a tube buffer then?
Well, first of all, how good is the digital component's analog stage?
We have been very successful with our tube modifications for the Oppo players and others, because we replace the stock analog stage with our own Class A, all tube analog stage, with zero feedback. Our designs also have low output impedance and can drive long cable runs no problem.
Most digital sources however (there are some exceptions at the much higher end), use standard op-amp based circuits, either single ended or balanced. Op-amps are inherently feedback based and they are cost-effective to design with. This is not necessarily a bad thing and many sound quite good.
To my ears however, no tubes, no magic!
Using a tube preamp with a SS based digital and even SS amps, works and we have done this for years. Our amps have mostly been SS and our preamps all tube.
However, for a simple system in which your main if not only source is digital, and has a built in volume control, then you don't need a preamp. This is where a tube buffer is ideal IMHO!
Our tube buffer design IS low distortion and does not limit frequency response.
My first intention with this, was to offer another option for lesser cost digital gear, alternative to a full tube modification at higher cost. I started with the Pro-Ject DAC because it offered DSD, MQA and SABRE DACs as well as HP amp and built in lossless volume control, for $350?! In stock form it is good, but a bit lean sounding. I found that when our tube buffer was added to the circuit, performance was tremendously improved, adding body and weight as well as a big 3-D sound stage! Now for this product, we also included a GOOD 5V DC regulated supply. The stock DAC operates from a 5V wall wart supply.
Now obviously, if it makes an inexpensive DAC sound this good, of course it will make a higher end DACs sound much better too. Brands such as Exogal, Mytech and other well respected DAC designs in a similar price range with built in volume control, would all benefit from tube circuitry.
And lastly, while you may change DACs with changes in technology, the tube buffer will never be obsolete. Also, being as how it is a separate unit, it can be used with any digital or analog source for the life of your system.
Ways this could be done:
1) Clean and simple tube buffer, one input (RCA) and two pairs of RCA outs, unity gain, no volume control.
2) Same as above, but add a well regulated linear supply for the source.
3) For balanced systems, a tube and transformer coupled solution would be ideal. At this point, it may be a two box design with external supply.
4) If more gain is needed, transformer coupling could offer +6dB and +12dB gain, without switching or volume controls.
Ultimately the ideal would be a compact, clean and elegant solution with minimal if any controls. It simply goes between your source and amp.
The buffer has the following benefits:
1) Impedance matching between any source and amp, offering a VERY low output impedance, allowing matching to any SS or tube amp.
2) Provides tube tonality and 3-D soundstage to a system without the need for a tube preamp or more costly modification to your source.
3) Optionally also includes an upgraded external supply for your digital source (could also simply be straight buffer).
4) Ultimately offering a big sonic upgrade whilst reducing system complexity (no preamp) and at reasonable cost.
Thanks,
Dan Wright
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Agreed to all of the above Dan. I also agree that most buffers suck, but that is because there are not any good ones.
I for one, have what I believe to be an excellent DAC, but it actually has no output stage. Its output is derived directly off the discrete resistor ladder DAC's. Makes for an ultimately transparent DAC, but it MUST have an excellent preamp after it or the sound is not meaty enough. This is another situation as to why I would like a buffer instead of a more complex line stage. It requires an excellent stage, but does not require a volume control.
My preamp volume is set, and I use the DAC to control volume via remote. Just a wasted feature that I don't need in my all digital system.
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I have a nice server based setup with a very good DAC, passive (Tortuga) preamp and class D amp, but no tubes anywhere. I'm thinking a tube buffer would be a good fit, but I'm trying to figure out where the buffer would fit in this system.
I have two RCA outs from my passive pre, one goes to my amp and the other to my subs, so ideally the tube buffer would come before it (between my DAC and preamp) but I'm not sure if that's where it is designed to fit. If the buffer works best between my preamp and amp and has two RCA outs, could I send one of the buffer RCA outs to my subs? Thanks for any clarification!
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Hi Paul79, don't you need some gain though? Is your preamp currently acting purely as an impedance matching device or is it providing gain? If the buffer was two-box, with external supply, then transformer coupling could be used to provide passive gain of +6dB to +12dB and the buffer would still serve as interface to the amp, and thus ideal VERY low impedance.
RE MttBsh, being as how the Tortuga is passive, it would REALLY benefit having a tube buffer between the passive and the amp. It would allow for the impedance matching at the amp. The two outputs could of course feed both the SW and the main amp.
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If this buffer is executed the way I have in mind sonically, this buffer could even benefit some active preamps too!
No gain required.
It also puts out 1.6V at around 600ohm I think.... Have to verify this. I have ran them amps direct. Very clear, like perfect sounding headphones clear, but no lower mid/upper bass grunt, lacks a bit of scale. It is designed to be used with a very good preamp, for this reason.
I am also strictly single ended all the way. Less is more for this guy.
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OK, that makes perfect sense!
The best passive preamp will sound clear and clean, but will lack body and drive. This is essentially what you have, with a very high quality DAC and no means of properly buffering the signal to the amp. The buffering really referring to the impedance matching. A good buffer will have an output impedance of well below 100 ohms. Clearly low enough to even drive an amp with 5K - 10K input impedance. Most amps have a higher input impedance than this.
In addition to the buffering and impedance matching, there is something that tubes add in terms of harmonic texture and sense of space. I am certain that it has to do with how our ears hear and receive the harmonics from a tube circuit.
I was listening to a very good Jazz recording recently, on vinyl, through our tube phono stage (PH 9.0) and the sound of the vibraphone was so palpable and the harmonics (nature of the vibes) was just incredible. SS just seems to flatten these harmonics and this, to my ears, takes away from the 3-D sonic presentation.
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What I think it begs for, is a nice low output impedance, no noise floor, black quiet, and a very high input impedance buffer. Like even 1MOhm.
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Also, even in the most proper situations, a passive can sound magic at one spot, then you touch the darn thing, and life is gone. Not for me. Ok if you want your system to sing at pretty much one volume. I like to have my volume set to several different levels, recording, time of day/night, mood dependent. Buffer please.
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Agreed, a buffer is needed!
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And you need to make it! I strategically posted here.....
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Looks like I'm in the minority about a volume control. My dac(s) don't have them and I wouldn't want to have to get a dac with volume control in the future. Perhaps a switch that could defeat volume for those who don't need/want it?
Unity gain is fine with me. Single ended, 1 in 2 out. Quiet enough to use with 100db + speakers and low output impedance, as mentioned. Protection from passing dc also. All that's worth $2k-ish to me. Doesn't need to come with tubes installed.
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Looks like I'm in the minority about a volume control. My dac(s) don't have them and I wouldn't want to have to get a dac with volume control in the future. Perhaps a switch that could defeat volume for those who don't need/want it?
Unity gain is fine with me. Single ended, 1 in 2 out. Quiet enough to use with 100db + speakers and low output impedance, as mentioned. Protection from passing dc also. All that's worth $2k-ish to me. Doesn't need to come with tubes installed.
There are several nice line stages out there with a volume control at or maybe a bit more than your budget. Dan makes some really great ones.
Dan. the volume control in my DAC is FPGA based and runs at 64bit at max volume. So allot of bits to throw away with attenuation, and never cause a sonic issue.
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There are several nice line stages out there with a volume control at or maybe a bit more than your budget. Dan makes some really great ones....
Could you show me some, please?
Again, need almost zero output impedance to biamp with solid state amplifiers, 6db or less gain, dead quiet for use with 100db+ speakers, tube output stage, volume, protection from dc (the only issue with the Microzotl). See reply #7.
The only difference you and I are looking for is volume control so I don't have to buy dacs with volume. Don't need multiple inputs, tape, invert, xlr, etc. Wouldn't vinyl only people also be interested in this buffer if it had volume?
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I am sure I could find something. I would do my homework. I would seek out companies that let me trial the products in my system to make sure they are what I am looking for. I cannot make any recommendations other than if I was looking to add features, such as vinyl, multiple sources, volume control, I would look for more of a full featured line stage.
I also, even in a bi-amp scenario, do not see why you would need almost zero output impedance? Depends on the destination components to a degree, and the load they present, sure. There are plenty of nice quiet tube preamps out there that have plenty low enough output impedance. Which is what the buffer would then turn into if you added all these features.
Maybe Dan can add all these things for you, I don't know, but I fail to see why some of your needs are actually important for your system. You might not find exactly the gain spec or the output impedance you are looking for, but within reason, you can get close.
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I am listening to all of you! Adding a defeatable VC is not a problem, just a high quality toggle. It is true that not every DAC has a VC.
I may start with a simple product offering as proof of concept with just RCA in-out and no VC. Based on field testing and feedback, we could roll out models with a larger feature set.
Thanks,
Dan
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I hope you do Dan!
Thanks for letting me rant here. I enjoy these discussions. See there Rusty? Looks like you are in the right place.
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All good! It is market research for me and who better than people who would be interested in our gear!
Dan
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Any thoughts on tube type? I really like 6SN7's. Even the low cost examples of this tube sound pretty decent and there's a wide variety of flavors to roll. I think their reputation for being too "tubey" and/or too microphonic is anecdotal. As always, a lot depends on the circuit design. Sure, their big glass is more microphonic than a small tube. There are dampers out there that help with this. In my opinion, 6SN7's do more right than wrong especially where tone and naturalness is concerned.
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My choice honestly will be 6922/d6j8/7308 family. This is because I like the tube, they are plentiful and in current production and their low plate impedance and high transconductance make them ideal for our circuit.
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Sonically excellent choice using the 6DJ8. No question. How are the new production ones of these holding up though Dan?
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I could be interested, but volume control makes it much more versatile in my opinion. (and for me the only useful option) At least 2 switchable inputs would also be nice.
Thanks,
Mark
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I am listening to all of you! Adding a defeatable VC is not a problem, just a high quality toggle. It is true that not every DAC has a VC......
Thank you for the consideration. Perhaps it could just be optional?
Paul79, I'm not sure why you think I'm looking for a full featured preamp. I'm after the same thing as you.......with volume control. :D
If you can find something that performs as well as the Microzotl and has protection from passing DC for that price point let me know. It's an amazing piece of gear. LTA just recently released a version as a full featured preamp with protection, but at more than twice the price. Can't afford it and don't need all the features.
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What level of protection does the microzotl provide or not provide? Does the protection actually include DC sensing and shutoff?
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What level of protection does the microzotl provide or not provide? Does the protection actually include DC sensing and shutoff?
The "basic" Microzotl (not the new MZ preamp) is a headphone amp that had rca outputs added so as to use it as a preamp. It's direct coupled, and if used with a direct coupled amplifier(s) and say you turn on the amplifier, then the MZ, or if they are both on and your power goes off/on it passes a large shot of DC when it turns on/back on. Dave Berning warned me about this, but when I was demoing it and had a brief power failure I honestly don't know how my speakers survived the surge. I immediately removed it.
My understanding is the new MZ dedicated preamp is the same circuit, but with a suppression circuit to prevent passing DC.
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I should also mention it (like all the Berning ZOTL designs) is one of the most transparent, best sounding pieces of audio gear I've tried. I'm sure the new dedicated preamp is superb, but it's pricey and too full featured for my needs.
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My choice honestly will be 6922/d6j8/7308 family. This is because I like the tube, they are plentiful and in current production and their low plate impedance and high transconductance make them ideal for our circuit.
Cool. I've had good experiences with 6DJ8's too. :thumb:
I totally understand people's desire for volume control and other features, but the more features that are added, the further away it gets from a simple in/out interface....and it becomes a unity gain line stage. Maybe 2 "mini" components makes more sense than just one? 1. tube buffer. 2. Unity gain line stage.
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OK, I see. The buffer is cap coupled in and out and there is a mute circuit that defaults to mute when powered off.
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Cool. I've had good experiences with 6DJ8's too. :thumb:
I totally understand people's desire for volume control and other features, but the more features that are added, the further away it gets from a simple in/out interface....and it becomes a unity gain line stage. Maybe 2 "mini" components makes more sense than just one? 1. tube buffer. 2. Unity gain line stage.
paul79 likes this :)
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(https://www.audiocircle.com/image.php?id=189049)
(https://www.audiocircle.com/image.php?id=189050)
Concept/proto of the Analog Bridge Tube follower. I am thinking $750 retail with one pair of RCA inputs and two pairs of RCA outs. No VC or balanced outs for this design. As shown includes a 5V DC, 2A linearsupply. Not sure if this would be part of the standard design.
Enclosure will be sexy and slim with MWI style. Designed to fit easily into the system with a compact footprint.
Next step concept drawings and enclosure design. Let me know if you want to be added to the wait list. This just means that we will contact you when it is available.
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Yes please. Add me. I also wouldn't mind evaluating it, and maybe help tune it if that is possible? I don't claim to be the end all or highest on the audio pedestal. I really do not want to come off that way, but do have a good idea of what I like and expect in a component. Ask Richard Colburn about me. He knows me quite well.
Speakers: Joseph Audio Pearl 3's
DAC: Totaldac Twelve MK2
Totaldac Server
Accuphase amps
Sutherland Line Stage
Room is big and treated nicely.
Zenwave for all analog
WyWires power cables
Looks great in there by the way!
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Will do! If you shoot an email to: modwright@yahoo.com, I will be sure that Kristin adds you to the list and you will be contacted when we have product to demo.
At this point, I am moving forward with the design.
Thanks,
Dan
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OK guys, I am moving forward with the design for the 'Analog Bridge' tube buffer.
I have a lot going on right now, so be patient, but I do believe this product 'has legs'. I am working on an enclosure design and the first product will be RCA in and out, one set of inputs, probably two sets of outputs. No volume control. It will be a buffer/impedance matcher with very low distortion, wide bandwidth tube circuit. It can be used between any source with built in volume control, straight to your amp. It can also be used between any passive preamp/attenuator and amp.
The two things that this product will bring to any system, is the 3-D body and weight of tubes as well as an excellent impedance match to your amps. With an ouptut impedance of < 100 ohms, it is ideal for this purpose.
Target price is $750 with (2)6dj8/6922/7308 tubes.
Once the initial design is out and I see how it is received, I will look at the following options:
XLR outs.
Volume control (w/bypass)
Multiple inputs.
I want to start with the simplest and cleanest design concept first to prove its worth and success.
Thanks,
Dan W.
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Excited about this! Any news?
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I'm sorry but I have been been buried recently, finishing two integrated amps and a new tube mod for the Pioneer LX-500. The amps are debuting at Axpona in April and I am buried. I have not forgotten this project!
Thanks for your patience,
Dan
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Good. Yes, don’t forget about it :) a MWI tubestage to throw between a passive and amp would be cool.
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I really just need to design an enclosure and the rest is good!
I will get this done after I send off the order for PCBs and other materials to mfg for the two integrated amps.
Thanks,
Dan
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If there is multiple inputs, volume control bypass and XLR outputs I am in !
This would help my setup with sound quality and source input problem with my current processor and maybe future one.
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One input and two outputs is PERFECT for the many many folks going from volume controlled DAC to amp. The second output allows for subwoofer out (or 2nd amp)....which most DACs don't accommodate.
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OK, I am getting there. I just got back from Axpona and recovered for a couple of days. Three new product releases there and leading up to the show about did me in.
I am getting back to the buffer design and will share my results as it progresses.
Thanks,
Dan
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Hi Dan,
The basic design makes a lot of sense to optimize DAC performance direct to amps and allow for sub integration.
I see you plan to expand the design after the initial release with a bypass option and XLR outputs. If you could squeeze in one additional analog input (to integrate your wonderful PH 9.0 *wink *wink), that would be the cat's meow.
Greg
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OK, so I have been doing some thinking about this project. Its scope could be from slim to broad. Does it make sense to design the enclosure such that it can accommodate all options as stated below?
1) Basic: Unity Gain, (1)pair RCA in, (1) or (2) pair RCA out.
2) Transformer coupled inputs allow for 0, 6, 12dB gain. This would not work with a passive, unless Transformer based VC, because of impedance matching. There is a sonic magic to transformer coupling. There is full galvanic decoupling, and a quality to the sound that comes from inductive coupling which is exceptional! This also achieves optional gain in a way that I prefer!
3) Volume Control: Volume control would be switched between input transformers and buffered output stage.
4) Multiple Inputs: Say 1-3 inputs, 3-way toggle. No need for expensive rotary selector or relay switching and PIC or microprocessor controls which unnecessarily complicate the design.
5) Balanced outputs: This could be accomplished with another pair of output transformers (expensive cost add). Or, with input transformer coupling, the use of four tubes could also accomplish the same goal. Best sound however may be achieved with transformer output coupling.
Summarizing options below, please let me know which configuration(s) would be of greatest interest to you.
Simple RCA-RCA Buffer.
Volume Control, switchable in or out.
+6dB, +12dB transformer based gain.
Multiple inputs.
XLR fully balanced outputs.
This begins to look more and more like a preamp, when you add in all options. I suppose it is a matter of semantics, but my goal is to produce a unit that will be the 'Analog Bridge' between your digital and analog source(s) and amplifier.
I would like to keep the size of the product fairly compact. It could be 17"W, but not necessarily. If a simple bridge, it could easily be 1/2 width.
What sets this apart from a preamp?
A preamp typically has remote control. This could be done, but then we are looking at adding a PIC and digital controls with clocks and other high frequency artifacts that would not be present in a simpler design.
A preamp typically has active gain and ideally a buffered or low output impedance.
A preamp may offer balance control, Home Theater Bypass, tape loop, etc. I don't want that level of complexity.
A preamp is a very active device. This would not be a passive device, but using transformer coupling for gain and unity gain active stage means there is VERY little room for noise to be added. Our power supply design and layout will rule noise out.
Simplicity and sonic purity are the goals of this project. I also want it to be affordable. It need not be dripping in billet AL and weigh 50lb. If offered factory direct to our mod customers, it could be reasonably priced. The more feature laden option would be more expensive of course, but still reasonable.
This could suit a main 'big rig' 2CH system.
It could work for a desktop system with powered speakers.
It could work with a headphone system.
It could be scaled to meet your needs!
Please post your thoughts and desires per my above comments.
This product WILL come to market, but I see an opportunity to make a very versatile product here, that would be unique and suit many peoples needs well.
Thanks,
Dan Wright
President, ModWright Instruments Inc.
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Hi Dan,
Your description sounds great. The buffer would be flexible for something as simple as a tube buffer with volume control to a stripped down version of a preamp. The half width would be preferable.
My needs are:
HT bypass (preferably a relay when unit is turned off)
2 outputs, one for speakers (my amps are balanced XLR only) and one for sub.
One analog input for phono stage.
Remote may be nice (for mute and volume), but not if it makes the case larger and adds too much cost.
Greg
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Thanks Greg, adding R/C and HTBP means that it would have relays, PIC and controls. Not a problem, but some added complexity and cost. Not a sonic disadvantage, just cost.
I appreciate the input! I can't move forward until I have an idea of what people want.
I plan to make it modular, so that it can be configured with different options that can also be added later.
Things like controls, HT/BP and R/C would likely be part of the core unit if the decision is made to include it.
I suppose this DOES become a replacement for a preamp.
The initial goal of this design, honestly, was to offer a low cost 'external' tube mod circuit, for use with any stock digital unit. After I built it, and I had a couple of people listen, I realized that it works well with all sources, analog and digital. Many people want to add tubes to their system, but don't necessarily want tube amps. This is meant to fit that need, as alternative to tube mod or tube preamp.
Thanks,
Dan
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Hi Dan,
I just sold an Exogal Comet DAC, and it sounded excellent when I tested it direct to my amps (clean and transparent). However, it sounded better when I ran it through my preamp. I assume the tube buffer would add a similar impedance match as a preamp to make a DAC sound its best direct to amps, but at a lesser cost.
Greg
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Yes, absolutely!
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Just curious, I know the Oppo players can drive some amps without a pre since it has built in volume, ~2.1 volts out and low impedance. I have a Levinson amp with 50K input impedance. Works well. Placed a schiit sys attenuator in between since I wanted to use outboard control, as some say the Oppo bit strips. Maybe. Anyway the schiit &%$! the whole sound. Replaced with a quality Goldpoint, transparent and works well. (I like it better than the Khozmo)
So I decided to plug a Manley Chinook phono stage (50 ohm output) straight to the Goldpoint. Works very well. Not sure why there's a feeling that digital source only can work great without a pre. I can get 100db across the room with some attenuator steps to spare. (JBL 89db efficiency and also a pair of JBL 93db)
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My needs would be :
RCA input X2
XLR input X1
XLR ouput X1
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I'm definitely interested. My needs would be volume control and two inputs. One input connected to a phono preamp and the other for home theater... Either HT bypass or use as unity gain.
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OK and thanks guys.
Analog or digital can work just fine into a passive attenuator. The problem with just a passive attenuator is that the impedance match between the passive and the amp input is not ideal. This can result in HF rolloff and will result in less drive and body.
The only reason that I first recommended the Analog Bridge as a solution for Digital is that the tube analog stage will make so-so digital sound much better. It is also a very high bandwidth, low distortion tube circuit, so it will not add unnecessary noise and distortion to any signal, digital or analog. What it will do, however, is offer the ideal impedance matching to any amp. The output impedance of the Analog bridge is < 100 ohms.
Thanks,
Dan
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Hi Dan,
Just out of curiosity, do you think the tube buffer with the input transformers could get close to the sound quality of one of your preamps or would a preamp still offer better sonics?
Greg
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That is a good question! It will certainly be quiet and with the 6dB-12dB gain and VC, it could replace a preamp!
It won't have all of the features of a preamp, including R/C I would say, although that could be done as well. It is just that pretty soon, what started out life as a simple box is now as complex as a preamp 8). Also the cost increases.
That is why the direction of this conversation is good and is helping me to decide and shape the concept of what this product will be! At first, it was simply intended to be an 'outboard' tube mod for use with any number of different digital products, rather than being fixed to one. Of course it is obvious that it not just be limited to digital sources and with a few simple features, could also replace a preamp.
To keep the design simple, the following are key I believe:
1-2, maybe 3 inputs.
2 outputs, optionally XLR fully balanced outputs ($$)
Transformer coupled gain, bypassable and configured for 0, +6dB, +12dB.
Tube buffer stage for Zout < 100 ohm.
Optional volume control.
I am thinking of a one-box solution, again to keep cost down and keep it simple.
To answer your question, I believe it would be as quiet, transparent and musical as a good preamp, yes.
Thanks,
Dan
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Hi Dan,
I can understand forgoing a remote and not having the HT bypass made active through a relay when the unit is powered off. I know I can get one of your preamps that offers those features.
Having a simple bypass would satisfy the HT integration need and the remote is a nice to have, not a must have. I just hate to burn through tubes when watching TV and using the HT bypass feature.
Greg
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Default to bypass when off is ideal! Yes, that would be the way to incorporate that feature!
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Hi Modwright,
I have a question for you but before I could ask it I was wondering what the ideal impedance for your preamp project would be? Thanks, Mark Korda
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The input impedance will likely be in the 50K range if a volume pot is used. If a pot is not used, it could be much higher than this. Most sources have fairly low output impedance. Tube sources can have higher output impedance.
Dan
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Hi Dan,
I was wondering why you were going to use tubes as a buffer and the transformers too. I made a copy of Jack Elliano's passive preamp transformer implemented in a Dyna PAM-1 chassis. There was an article in AudioXpress showing the simple circuit. I get the 6db of gain from the transformers stepping up but don't see how putting tubes in would benefit. I'm a little confused with the input and output impedance stated thru the article but will find out.
I used Goldpoint stepped pots at 10K
(https://www.audiocircle.com/image.php?id=194345)
I use a Dyna ST35....Mark
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Hi, the transformers can be configured with different impedance ratios and provide gain or attenuation. I don't see how a transformer configured for gain would allow for good impedance matching however. A transformer can only reflect back from either primary or secondary of the transformer, a given impedance. A transformer configured for gain (step-up), will result in a higher output impedance than input. Conversely, if a step-down (attenuation) transformer is used, the output impedance of the transformer, as seen by the following component will be lower than the input impedance.
The reason I am using a buffer here (tubes only because I prefer the sound of tubes, but could also be a SS buffer), is to guarantee a very low output impedance as seen by the following component. If I wanted to add gain, I would use a step-up transformer, followed by a volume control, with the buffer at the output of the unit. This would guarantee an ideal output impedance to match the amp to follow. The input impedance seen by the preceding component would be a factor of the volume pot impedance and the winding ratio of the step-up transformer.
I hope this clears things up a bit.
Thanks,
Dan W.
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I am blown away how generous Dan is with his knowledge and accessibility. I for one admire and appreciate Dan for his efforts.
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Thank you! I use this forum as a sounding board for new designs because, quite frankly, you are all my customers! I want to design a product that our customers want!
Dan
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Hi Dan, thanks for taking the time for that answer....sincerely Mark Korda
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Analog or digital can work just fine into a passive attenuator. The problem with just a passive attenuator is that the impedance match between the passive and the amp input is not ideal. This can result in HF rolloff and will result in less drive and body.
It might depend on the amp used, and interconnects as well with just a passive attenuator, I have tried 2 other amps that did have less drive and body, but the Levinson I'm using actually provided more body and drive with a passive. The HF rolloff I'm not sure, there is some, but that may be due to the having more body.
I'd be interested in a solution that simply had an attenuator, and a mechanism that guaranteed impedance matching, no gain, and a few inputs. Adding tube is nice, but for those that have something like a modwright oppo and a tube phono stage, maybe just need the above, or maybe I'm way off base.
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What you're asking for is sort of a "Holy Grail" line stage. There are devices out there that do as you describe, but all have compromises in one way or another. There's no universal solution, though some come close to that ideal.
This is why I'm +1 for just a simple buffer with at least 2 outputs. This doesn't add another lossy attenuator in line for folks already using sources with very good volume controls. Tube or solid state doesn't make much difference to me as either can be tuned to produce sound as the designer (Dan in this case) wishes. Tubes just provide more flexibility on top of the design's "house sound."
Maybe there's a way to do 2 versions? A decked out version with volume control and more ins/outs and a base version without volume control and maybe just 2 ins/outs (and a toggle switch to select inputs A or B)?
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You are absolutely right and that is why my intent is a very modular design that can be simple or more advanced. I will have to give some thought to the enclosure design that can accommodate all of this.
The initial product was to be just as you described, a simple buffer with inputs and outputs.
Add options would be:
Volume control - defeatable.
Gain via step-up transformers, adjustable.
Balanced outputs - tube or transformer based.
Advanced controls and HT/BP.
Perhaps the Volume control is standard and can simply be defeated.
The controls may be relay based just to include the HT/BP as this will not add much cost/complexity.
The transformer gain module could be added.
The balanced output transformer based module could be added.
Doe this come closer to a solution that will appeal to all?
Thanks,
Dan
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Dan, so if you had just a tube buffer by itself, this would guarantee constant impedance matching, given just a source component and an amp?
If so and in my case, would it then be placed between attenuator and amp?
Could you also eplain a bit how a buffer accomplishes this? Thanks.
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Yes, that is exactly right. It offers a fixed output impedance < 100 ohm.
A tube buffer circuit offers a very high input impedance, unity gain and very low output impedance. This is accomplished simply by the nature of the SS or tube circuit. Many SS buffers are unity gain op-amps which apply 100% feedback. I don't like global feedback, nor do I like opamps.
I use tubes for nearly all of my line-level circuits because I prefer the sound of tubes and lack of need for global feedback. Most tube buffers use one form or another of a follower circuit. Ours uses a fairly advanced follower circuit that offers VERY low noise, distortion and WIDE bandwidth. It also achieves the desired goal of offering VERY low output impedance to match with any amp.
It is the ideal way to improve the best passive attenuator. The attenuator is sonically transparent, but the impedance match to the amp will never be ideal without a buffer or other way of impedance matching.
It also works ideally with any digital or analog source with a built in volume control.
Dan
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Sorry for the questions, but I'd like to understand,
Let's say I have a source component --> passive attenuator --> amp.
The source component spec is 100 ohm output impedance, the amp is 50K input impedance. (The source component has let's say 1.5-2V out)
What is happening? I'm assuming the interconnects are changing the impedance somewhat, so we're not 100 ohm anymore? But is it the increasing signal from the attenuator causing the amp to change load, which makes the impedance the amp sees change, as well as something like transient spikes which might be worst case? Ohms constantly fluctuating or just consistently too high maybe?
Also what would be some examples sonically if the impedance is not ideal?
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OK, here is the explanation for that.
The source component has an output impedance of 100 ohm. If it had a built in volume control AND the output was properly buffered, it could be connected straight to the amp and the impedance would match. As to how it would sound, depends entirely on the analog stage circuitry and volume control of the source.
When you feed this to a passive attenuator, say with a 10K impedance, the output impedance of the attenuator is the same as the input impedance = 10K. So you are then interfacing 10K with a 50K amp input impedance which is not ideal.
The exception to this would be a TVC, Transformer Volume Control, which are expensive and have their own set of rules!
The buffer would be ideal to use between the passive volume control and the amp. It would take the 10K impedance of the pot, seen by the 500K-1M input impedance of the buffer and offer an output impedance of < 100 ohms to the amp's 50K input impedance. This impedance matching, current buffering and handling of the signal by the tubes will give you more body, weight and authority to the sound without any loss of frequency, detail or bass.
I hope that this makes sense.
Dan
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That's a great explanation, Dan. Complicating matters is that (some, but maybe not all) passive attenuators don't always output a constant impedance either. It can vary, right?
A buffer alleviates this complexity.
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My dream configuration would be 2 inputs, one balanced, one not.
Maybe 2 outputs but not a dealbreaker
And not much else
And it has to be pretty, but knowing MW’s styling preferences I don’t see that being a problem
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OK, balanced inputs and outputs are not a problem, but do require either four tubes or four transformers, which adds cost.
Aesthetics will be good, but depending on how sexy, will dictate price!
I am envisioning a steel box with a nice AL face plate. If you really wanted it to look nice, we could also machine the entire thing out of solid Billet, but that adds at LEAST one zero to the price tag! I would prefer to have nicely powder-coated steel with an AL face. Probably silk screened graphics.
I am envisioning something along the lines of the PH 9.0 phono stage, in terms of aesthetics:
http://modwright.com/sources/ph-90-tube-phono-stage.php (http://modwright.com/sources/ph-90-tube-phono-stage.php)
Considering that I was envisioning the simplest version, with RCA's in and out, buffer stage and no volume control, gain or transformer coupling, to start at $750, you get an idea of the cost.
I appreciate the input and continued discussion here as it all helps me to shape this into a project scope that will suit everyone's needs as best as possible.
Dan
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Function over form for me, I'll take the cheapest box option :)
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Well, the spirit of this product is that it be more function than form. Of course it won't be ugly, I DON'T DO ugly ;). But, the money will be spent on design over aesthetics. This is mean to be a product for the mod end of our business, sold factory direct.
Thanks,
Dan
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I’m sure it will be awesome regardless of casework and features
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Thank you, this is shaping up to be a great design and I am confident that it will fill a much needed niche for modern systems. It will provide exceptional sound in today’s more simplified and sonically pure modern analog and digital systems.
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When you feed this to a passive attenuator, say with a 10K impedance, the output impedance of the attenuator is the same as the input impedance = 10K. So you are then interfacing 10K with a 50K amp input impedance which is not ideal.
The buffer would be ideal to use between the passive volume control and the amp. It would take the 10K impedance of the pot, seen by the 500K-1M input impedance of the buffer and offer an output impedance of < 100 ohms to the amp's 50K input impedance. This impedance matching, current buffering and handling of the signal by the tubes will give you more body, weight and authority to the sound without any loss of frequency, detail or bass.
Dan
Hi, Goldpoint attenuators:
http://www.goldpt.com/info.html
"Ideal" may need to be more specifically defined.
"Matching the volume control value to the amplifier/pre-amplifier input impedance is not as important as some people think, so you typically don't really have to worry about this. For a 100K input impedance, use a 100K, 50K, 25K, or even a 10K level control. This applies to passive preamps, active preamplifiers, and power amplifiers when the control is to be installed at the Input."
There's also a lot more on that page that reads very interesting.
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I am talking specifically about adding a passive attenuator between source and amp, where there is no active circuitry following the attenuator. In that case, the output impedance seen by the amp IS the impedance of the passive attenuator. True, a 10K passive into a 100K input impedance amp is not bad, but with the rule of thumb ideally being 1:100, not 1:10, you get the idea.
I speak from both experience and engineering knowledge. Before I fully understood why, I used a number of very high quality passive attenuators and the Goldpoint is a great one! It is a great volume control, period! I am just saying that if you use even the BEST passive attenuator between source and amp, there will not be a good impedance match.
My personal experience many years ago was that, while the best passive, always sounded very clean and quiet, it lacked body and weight. I then added an active preamp and found the body and weight that was missing. After this, I always used an active preamp. It has to be a GOOD active preamp however!
I have since learned that it is really a matter of impedance! The use of a good buffer AFTER the Goldpoint or similar excellent volume control/attenuator WILL give you the best of both worlds! The active circuitry must be good, quiet, well designed and not harm the signal of course. I have long since determined that adding circuitry to the signal path is NOT always a bad thing! The same can be said of signal path transformers.
Many of use believe that less is more, always! I don't agree with that 100%. I am not a fan of tone controls and I am not crazy about DSP, because it all involves manipulation of the audio signal, in ways that often creates more problems than it solves. I don't like my analog digitized and I find that when any signal is digitized, manipulated and decoded again, there is too much lost. DSP room correction for low frequency issues IS a good thing, but I would NOT like to have the entire signal treated with DSP.
Now, we are not talking about digital or DSP, but it illustrates a point of adding circuitry for a net positive gain...or not!
Many people feel that adding signal transformers will always limit fidelity. I believe this comes from the fact that tube amp output transformers, especially SET transformers, must be very well designed, in order to not limit bandwidth and add distortion due to core saturation. I will argue in this case, that well designed SET transformers can and will produce the MOST BEAUTIFUL music playback when done well!
Push Pull tube amp output transformers are MUCH less impacted by the issues that SET transformers are because there is very little net DC voltage seen by the core. As long as global feedback is not used, P-P tube circuits can be AMAZING sounding and with very good BW! Our P-P 300B Integrated is flat to 50Khz!
Non-gapped, audio transformers (do not see DC voltage) are an entirely different matter. I use Lundahl line-level non-gapped transformers extensively in our best products! Jeff Rowland has done the same for years, also with great results. Yes, you are adding a copper coil and magnetic core to the signal path. However, you are also getting galvanic decoupling, inductive reactance and out of bandwidth filtering (say > 60Khz rolloff) which is ideal for digital circuits. Transformers can also attenuate signal level and allow for impedance matching. They are amazingly useful and musical reactive devices! I would much rather create a fully differential balanced output from a single ended circuit with transformers than use op-amps (feedback based) or other active circuitry to achieve the same!
So, to sum all of this up...
The addition of a tube buffer falls into the same camp of addition to the signal path WITH net benefits, not sonic degradation. For the design with gain, we will use transformer coupling and likely the same for balanced input and outputs. The tube circuit offers very low distortion, very low noise and bandwidth flat from 20Hz-100Khz.
Those using Goldpoint or other high quality passive volume controls will find that the addition of our Analog Bridge after the attenuator and between the amp will offer VERY welcome sonic improvements!
Thanks,
Dan
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What is a good or ideal impedance match? Specifically please.
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What is a good or ideal impedance match? Specifically please.
Preamp output impedance 0 ohms, amplifier input impedance ♾.
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1:100 is the ideal ratio. So for 100 ohm out, 10K min input impedance for amp, min. The higher the ratio, the better , but 1:100 is min ideal.
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So still the Goldpoint link states that it's not as important as people think. So there's another camp I guess.
Also I can't help but think that a) it can't possibly be good to add more processing in the path and b) the sound will change especially if tubes are involved, which would sort of imply impedance mismatch may have had nothing to do with the new different sound, hope that made sense.
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Preamp output impedance 0 ohms, amplifier input impedance ♾.
No trying to be a smart ass, but how did you arrive at those values?
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No trying to be a smart ass, but how did you arrive at those values?
It's a theoretical ideal. It would make the current/voltage conversion also ideal.
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There are always different views and ideas about things. Impedance relationship is a hard fact and the math will prove this out and it can be verified by test equipment. I won’t dispute that tubes produce their own sonic signature and not everyone likes tubes. I do and our customers have also been very pleased with our products’ sound.
Use of a SS buffer would achieve the same impedance matching and would have a different tone than that of a tube buffer.
There is no question that a great passive attenuator will produce a very clean sound. I am simply expressing that what I heard when I tried this many years ago was good, but I felt that I knew what was missing, to
my ears, when a good active stage was used between attenuator and amp.
I am not posing this as an argument. Impedance relationship is a fact. We do all hear things differently and as a result, we will have different opinions about what we deem as best sound. Those who know me and our products and how they sound, will like what they hear with this product.
Different opinions are always respected here and by me personally.
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I ran an Exogal Comet DAC direct to amps (as an experiment) to see if music would sound as good as without a preamp. The Exogal Comet has a ridiculously low 18 Ohms for the XLR outputs. It sounded very clean and had no problems driving my amps. My amps have a 20k input impedance.
The Ambrosia preamp has a 29k RCA input impedance and 100k XLR input impedance. The output is 60 Ohms (higher than the Comet Direct). When the Comet was ran through the preamp the music gained weight, body, and air.
I guess what I am saying is there is more to the story than just impedance. Other design elements come into play. I currently own Dan's PH 9.0 SE phono stage (killer by the way), and I have owned other products from Dan in the past. Dan has a deft ear for getting good tone with lots of detail, without adding distortion.
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True, current buffering is also very much a part of the process. Lastly, adding to the signal path is OFTEN not
detrimental, if the design is done Wright!
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True, current buffering is also very much a part of the process. Lastly, adding to the signal path is OFTEN not
detrimental, if the design is done Wright!
Nice, I see what you did there. :lol:
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Well, if the impedance deal is real, then why not just build or use something like a 2.5K ladder network attenuator, by itself?
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Well, a 2.5K ladder attenuator gives you a 2.5K input impedance seen by the source and a 2.5K output impedance seen by the amp. Neither is ideal.
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Dan
Just a quick note to say that I am new to this forum and I am looking for this type of product right now, so please count me as another potential buyer in your market calculations :-)
FYI...I am running one of your 100SEs off a T+A DAC8, using the preamp in the DAC, its pretty good, but cant wait to see your product on the market.
Good luck with the design.
Regards
Colin
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Thank you! I am working on two big integrated amp designs right now and trying to get them finalized. There is clearly enough interest in this product and I will now start putting it tall together in the enclosure design as well as the options available and layout. I will post images and have more questions in terms of market research as I move forward into this next phase.
Thank you all!
Dan
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What’s the status on this?
Busy working on the new integrated I assume
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I am actually in Europe with my son at the moment. We are on a train from Berlin to Amsterdam.
I will be back to work on the 12th of August. I am finalizing two integrated amp designs and will be getting this to market too.
Thanks,
Dan
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Hey Dan enjoy the trip. BTW great idea. Integrated amps are IMO the way to go.
charles
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What a cool thing to do, its these sort of things that make great memories...enjoy the trip.
I wasn't sure if the draft design ended up with a remote control for the volume or not, so just wanted to put my view on this.
I understood the original target market was for people that had mostly an all Digital chain in their system (excluding amplifier and speakers of course). If that is still the case, and if you were putting a volume control in the design, doesn't an R/C become almost mandatory for digital sources. My reasoning is that for Digital streaming from web based streaming services volume varies so much in between albums and across streaming services, and especially internet radio. My experience is that volume adjustment through an evening of listening would occur at least a dozen times, perhaps more, and its a pain getting off the couch to constantly adjust volume, and not to mention volume adjustment (read fighting :lol:) when two people are listening. Its not so bad if you are streaming from locally stored music files and have enabled volume levelling , although some implementations of software levelling leave much to be desired as well.
I dont have a problem with excluding a volume control, there are pretty good volume controls in DACs these days and they all have R/Cs, but if you do have one I think an R/C has to be included. Perhaps it could be an option to have a volume control switched in or out of the circuit...not sure if this feature would be detrimental to sound.
cheers
Colin
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Good point and noted. If VC is included, R/C would be too, as well as a defeat/bypass option.
Thanks!
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Let us know what Amsterdam is like.
Never been there, or the continent at all for that matter.
My younger sister lives there, thinking of checking it out (she’ll know where all the good record stores are :) )
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Amsterdam is a fun and crazy city. We were there for the weekend and there was a celebration going on, so it was doubly crazy. Very beautiful city and great architecture. Second to Prague, it was one of my favorites. We visited Munich, Prague, Berlin and Amsterdam. We enjoyed Prague the most and will definitely return!
Thanks,
Dan
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Dan,
This is OT, but inline with your last post.
Did you use a travel company to arrange your trip to Munich, Prague, Berlin and Amsterdam, or did you make all arrangements yourself?
I'll sheepishly admit that I've never been to Europe. 98% of all my travels have been in Asia, and 2% have been in Canada and Central/South America.
Michael
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Well, it is funny that you should ask. I did it all myself and it worked out for the most part, but I will share my experiences about what NOT to do!
First of all, booking airfare is easy and I use Hopper to book airfare. This app is great, because you can put in the times and where you want to go and it will tell you what current fares are, if they are likely to go up or not and when is a good time to purchase. So, that is how to handle airfare to-from Europe.
I would recommend planning your trip, so that you fly into City A, and fly out of City B, where you plan to end your trip. In our case, we started in Munich, then took a train to Prague, train to Berlin, train to Amsterdam and I had planned a final train back to Munich, but it would have been 10-14 hours by train and in the end, I spent $300 for two one-way plane tix and it was a 1:20 flt. I would have booked us into Munich and out of Amsterdam, but I bought the plane tickets before I knew exactly where we were going.
Within Europe, you can travel by train, which is easy and relatively affordable. I spent about $800 on a 15-day twin German rail pass, for two of us, that allowed us to travel on any trains in Germany at any time, within that 15 day window. It also covered domestic trains in the cities, BUT NOT SUBWAYS! I also made a bad assumption that it covered trains from Germany to adjacent countries, on German trains! Not so! I ended up paying a bit more, for the train leg from the border of Germany and Czech, to Prague, and from the border of Germany and NL to Amsterdam. I probably would have been better off with a Eurail pass, which costs a bit more, but covers trains to all countries.
Now, I would also consider the cost of flying between countries within Europe also, because this is faster and may surprise you at the cost. Trains are convenient and inexpensive. Recommended for max 4-5 hour trips between cities. When you factor in the time to get to the airport, security, the flight itself and then from the airport to the city, often a 4 hour train ride is just as fast as a 1 hour flight! Trains are easy to hop on and off, no security and airport delays.
As for accommodations: AIRBNB! It is THAT simple! This is the BEST WAY TO GO! Look at ratings and see what is there, but you will save money and we had GREAT experiences with this! In Prague, we had an entire flat to ourselves for about $75/night! In no case did we pay over $100/night for Airbnb's, while we paid over $150/night at average hotels and they were not as comfortable.
So, you could use a travel agent, but I really don't think it is necessary. It really depends on who you want to travel. This was my 16 year old son and myself. We had a backpack each, med size and no checked baggage. We wanted to be flexible and free to change our minds about where we wanted to go. The rail passes made sense in this regard.
Once you arrive in a city, public transport is very easy and inexpensive in most cities. Worst case there is also uber, for a bit more, if you in a pinch or don't want to deal with subway or train.
So to sum up:
Pack as lightly as possible, so you are not lugging a bunch of luggage around.
Use Hopper or other site to find the best flight rates and times.
Decide on rail or planes within Europe. We had a good experience with trains, just get the right kind of pass.
Airbnb is the cheapest and most comfortable accommodation option in my opinion!
Public transport within Europe is cheap, fast and easy.
Use a credit card WITHOUT international transaction fees as this will give you the best exchange rate for all transactions. You will need minimal cash in Euros, etc. Cash exchange is NOT going to be at the best possible rate.
I highly recommend Prague and Amsterdam! Munich was preferred by us for the German experience. There is also France, Italy, Greece of course. I am just sharing our experiences and I hope that it helps.
Thanks,
Dan
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Dan,
Very cool. Thank you!
My wife and I had hoped to go this year, but things and events kept us from going.
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You are most welcome. My son and I did the trip kind of like college students but without hostels and a bit more resources ;).
I hope that you and your wife find the time to go. Truly well worth it!
Dan
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Hi,
I'm interested, my wants would be as follows,
1: No volume control so Unity gain I guess
2: Remote for all functions ie:Power on/off and input select(No Input select knob required), 3.5mm mono plug on the rear of the enclosure to integrate into a IR
repeater setup, all of my gear sits in another room
without line of sight.
3: 2...max 3 inputs, 1 of them being HT/BP, must automatically default to this input when powered down(same as your LS36.5 if I've read the manual right?), 2
outputs
4: 6SN7 tube compatability(I have a few already, and like to roll occasionally).
5: 240v, I'm in Australia!
I have a 5.2 system, when listening to music its 2.2, currently have a tube line amp that I had custom made here in Aus by a well respected tube amp maker, all hand soldered, point to point, Alps Blue 100k pot(which sits at 12 o'clock and never moves as volume control is upstream) I love the sound of it, it has HT bypass too, a no brainer for someone like me who doesn't have the space or funds for a dedicated 2 channel system, as much as I would like one, I had a Parasound P5 for awhile, very convenient, but hated the sound of it, fatigue after an hour of listening. Got my tube line amp and peace was restored, to my galaxy anyway!, but not very convenient without any sort of remote.
My DAC is a miniDSP 2x4 HD(stop laughing!), however its perfect for my needs and sounds better than the P5 ever did, even before my line amp was added, as it has very fine control over input/output levels, XO's etc. My subs bypass the lineamp, as I feel that they sound better without the tube stage added, 'tighter' for want of a better word.
A steel case with a 5mm thick aluminium facia is perfect. To help keep costs down make the backplate modular so it can be used on different input/output versions of said buffer.
Anyway, looking forward to what you come up with, :popcorn:
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OK, thanks. And the really big question here of course, is what do you expect to pay for this, as described, at retail?
I appreciate your input!
Dan
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Hi Dan,
Welcome back, I am glad you had a memorable trip with your son.
Greg
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Thanks GregC!
Dan
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I highly recommend Prague and Amsterdam! Munich was preferred by us for the German experience. There is also France, Italy, Greece of course. I am just sharing our experiences and I hope that it helps.
Thanks,
Dan
I would like to also recommend Spain. My wife and I just returned from a 3 week trip that started in Madrid, then Barcelona, then Nice and finally a week in Paris. As much as I love Paris - and Nice was particularly beautiful, driving along the cliffs to Monaco - Barcelona for me was probably the highlight, an absolutely beautiful city. It's like a warmer and decidedly less expensive version of Paris, nestled on Mediterranean, we stayed at an affordable AIRBNB right on tree lined La Rambla boulevard where some of the best restaurants and entertainment are just steps away. Can't recommend it enough.
Oh, and Dan, thanks for the updates on the tube buffer!
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Thanks, while I have been in Paris only briefly, I get the feeling that there are other places equally if not more beautiful and I have certainly heard of Spain being quite beautiful!
Dan
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OK, thanks. And the really big question here of course, is what do you expect to pay for this, as described, at retail?
I appreciate your input!
Dan
US$1500 or less, too much competion is this space, ie: Schiit Freya+, Musical Paradise MP-701, WBA-Firebird, and a bit more Tubes4Hifi SP-14
Hope this helps
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Fair enough. I was not planning to be extremely cheap, but also not super expensive. That range is right where I was thinking, +/- depending on options.
Thanks,
Dan
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Hi guys, the nearly 13K views of this thread have not gone unnoticed and I have not given up on this product at all! In fact, I am nearing a point where I can pursue it fully as I am finishing two designs that have kept me very busy for the last year. The KWH 225i Hybrid power integrated amp is about to roll out and the Ai325, 300B 25W PP tube integrated has also been VERY WELL received by the first customers lucky enough to receive the first hand-built amps!
The next step is for me to lay out a matrix of options and ideas for this design. Things like quantity of inputs, balanced inputs/outputs, volume control, DAC supply built in, etc.
The plan is as follows:
A chassis will be designed to accept the buffer circuit and power supply design.
Enough room will have to be allowed for to accept the following (but not limited to) options:
Volume control, defeatable.
Tube rectifier.
Multiple inputs/outputs.
Separate power supply output to DAC(s) - ideal would be adjustable voltages and connectors for different DACs with wall wart supplies.
Balanced inputs/outputs - getting more costly here as this requires transformer coupling!
I do NOT plan on offering the following:
Tone controls.
Balance controls.
tape loop or any other processor loop (would like consider Home Theater Bypass however).
No DSP of any kind - purely analog design.
The plan being to design this in a relatively compact enclosure with a clean and simple face plate. Steel enclosure with black powder coat. Maybe silver and black face plates.
Basic model being just a buffer with no volume control and possibly two inputs and two outputs.
Starting price of this product to be < $1K.
Basic buffer circuit will offer:
Very wide frequency response - 20Hz - 100Khz
Very low distortion < .05%
Very low output impedance < 50 ohms.
As such, it will introduce tubes into the system without adding the typical soft bass, rolled off highs and added distortion. It will offer ideal impedance matching to your amp(s).
It can be used in a stereo speaker setup or with headphones.
It allows the system to be as simple as:
Source - Buffer - Amp - Speaker.
Source - Buffer - Powered Speakers.
Source - Buffer - HP amps - HP's.
In addition to being a buffer, it can ALSO be the UPGRADED linear supply for your DAC! I know that many people are getting tremendous improvements from adding external linear power supplies to a number of modern DACs.
This will be much cheaper than our mods to digital products and may be used with any number of different sources.
It can replace a preamp in a simple system and avoid the need to use the digital volume control built into many DACs!
With the DAC supply option, it also offers an upgraded DAC supply to a variety of DACs.
The key being to make this modular.
Please share your FB here as I take this from concept to reality!
Thanks,
Dan
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I'd happy with all of these and be even more happy with balanced I/O :P
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I'm really hoping the home theater bypass can come to fruition.
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OK, thanks. I believe that inputs will be relay driven, so that it is not hard to add HTBP, more than one input and optional VC, defeatable of course.
Balanced IO's require either op-amp circuits - NOT GOING TO HAPPEN - or transformer coupling, and this gets expensive! It could certainly be done and I would use PCB mount line-level Lundahls if so, because of their exceptional shielding and hum-bucking abilities. Because this will be sold direct, the cost does not have to be prohibitive, but that option WILL cost more.
Thanks,
Dan
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I really like the LPS tap(s) for sources. What are you planning on there, 5 volt 3 amp? Variable voltage? How many taps?
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The basic model is probably all I need in between my Bryston DAC (and future phono pre) and KWI 200 integrated.
No volume control, 2 inputs.
Balanced might be nice but would it be balanced or normal RCAs, or a combination of both?
The Bryston has balanced outputs but any phono pre I buy most likely will not.
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As for LPS for DACs, I need to see what voltages are most common. 5V is very common of course and there are also others. There is also the issue of connector size, etc. We can work out a cable that connects to our unit at one end with a fixed connector and then has variable size connections on the other end. There is more to flesh out here, but yes, that is the idea!
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Just my opinion, I would not go for the DAC LPS.
Why ?
Highend DACs could benefit from the buffer, but not all (very few) uses poor external PSU.
Most uses inner good LPS or even better external.
But tube stage is not always an option for these.
+ I prefer an LPS specific for each of my gear units.
My only "shared" LPS is a HDplex but I bought it for that purpose and it feed only small boxes. The goal was to remove the SMPS out of my network.
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DAC LPS - make it an option.
Volume - defeatable = great!
HT bypass is a must have for me, and as I mentioned previously, have it default to this input when buffer is powered off.
I dont need balanced in/out, another option for some. RCA 3 in / 2 out is enough
No mention of remote control in your recent posts? please add a 3.5mm IR 'in' plug on the rear panel.
:popcorn:
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Same question, if there is no remote control...then I would not consider this device. Otherwise its on my radar.
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6SN7 tube compatibility would a 6SN7 tube work well in my system.??
(Oppo 205 "6DJ8" & Decware ZMA "6DJ8" / "el34")
Remote Volume Control & Balanced in/out,
Are the options that are interesting me in this product..
I have my Modded Oppo 205, connected directly to my PP el34 amp with a XLR cable..
I have to use the Digital Volume Control on the Oppo 205, I would rather use the oppo wide open (100%) and have a remote volume control..
Does a volume control degrade the signal..? How.??
Thanks, BURT (From Fresno)
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R/C volume is no problem for units with volume control.
It will be 6dj8, because this tube is best suited for the circuit that I am using. I know that the 6SN7 tube is popular, but it is not suited to the design I have planned.
Thanks,
Dan
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This type of product is exactly what I'm looking for right now. My amp is 11K input impedance and I'm using one of your SWL 9.0 AE's with it, but would love a tube buffer in between them. I'd go for a basic version w/o volume control, but I'd possibly add the balanced outputs. And of course I would need a silver faceplate.
When can we expect these to come out?
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I'm working on it!
The new KWH 225i Hybrid Power integrated and Ai325 PP 25W 300B integrated amp have been keeping me from it, but both are now at the finish line, so I am investing energy into making the Tube Buffer happen!
Look for more information after the holidays.
Happy Holidays to All of you!
Dan W.
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Topping D90 is probably a good contender to review. https://www.audiosciencereview.com/forum/index.php?threads/topping-d90-balanced-usb-dac-review.10519/ (https://www.audiosciencereview.com/forum/index.php?threads/topping-d90-balanced-usb-dac-review.10519/)
I get that measurements are not everything but is it wrong to think they are the foundation to build on?
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Well, measurements are important. I also prefer to listen in addition. Both are part of my process.
Based on the AKM DAC used and the measurements, it looks like a good product! I am not bothered by the higher frequency elevated THD+N and lack of Brick Wall filter because I prefer the sound of smoother filters. The price is very attractive. I don't know anything more about it, but it looks very tempting!
Dan
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Hi, any chance the enclosure size would be identical to the PH 9.0 which I own?
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That is the plan! Yes, an enclosure that size would be ideal.
I know this is taking a while guys...very busy right now and I AM still working on this! It is a great product!
Dan
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Dan, if you get this pulled off I am in for one, please offer a fully balanced option, it is worth it to me.
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Thank you all, for your suggestions and your patience! The KWH 225i and Ai325 integrated amps have taken me much longer to finish than expected. The first KWH 225i's ship tomorrow in full production form and we have backorders to fill. The Ai325 will follow shortly thereafter. I will then pursue this design aggressively!
Dan
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Dan, any more thoughts on the timing of development on this?
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I have to be honest, it will likely be Spring/Summer at this point. I just got back from the VPI house over the weekend where I presented to dealers and our new KWH 225i and phono stage designs of our own production are eating all my time and resources.
I WILL finish this design! I am just stretched so thin right now. I am CONFIDENT that this product will be a HUGE seller for us...If I could only clone myself!
Thanks,
Dan
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I have to be honest, it will likely be Spring/Summer at this point. I just got back from the VPI house over the weekend where I presented to dealers and our new KWH 225i and phono stage designs of our own production are eating all my time and resources.
I WILL finish this design! I am just stretched so thin right now. I am CONFIDENT that this product will be a HUGE seller for us...If I could only clone myself!
Thanks,
Dan
Hi Dan,
You do an awesome job of creating innovative products AND being accessible to your customers.
Greg
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Thank you, I appreciate that!
Dan
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Thanks Dan for looping us in.
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You bet! Believe me, I WANT to get the Buffer to market!
Dan
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This won’t make me popular but I think you should charge more for the tube buffer. If you put a volume control on it, people will use it as their preamp. It could become a popular item and people will judge the modwright brand by it. You want to make it worthy to represent your brand
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Ummm. Uncola, that would make you very unpopular with me. :|
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But I also think you should give a large discount to all the people in this thread, your most loyal devoted customers who you know you can rely on to give feedback ;). Yay I’m popular again
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Redeemed. :lol:
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OK guys, I have a solution!
The retail price of the buffer will start at $5K!
But, I will give everyone here a $4K discount! :lol:
:popcorn:
To be honest, I have not set the price yet, but at or around $1K is the expected base price. It will be offered with options that will add cost. I first want to get a basic prototype out for people to hear and give me feedback. It will be just the tube buffer, that can be run in-line with any digital source. The next step will be to incorporate optional linear supplies for the DAC(s) that it could be paired with. Then I will look at volume control, multiple inputs, etc. I first want to prove the simple concept of the wide bandwidth, low distortion and VERY low output impedance buffer circuit.
Just yesterday, I got tired of listening to my Logitech Squeeze box as source - burning in amps, etc. So, I took a digital out from the Squeeze Box to the Pro-Ject S2 DAC, feeding the tube buffer, out to our integrated. WOW that was better! Now, keep in mind that I am streaming Redbook, wirelessly to the squeeze box. All I did is take the coax out from the Squeeze Box to the $300 Pro-Ject DAC with the buffer! The difference in sound quality was startling! The buffer adds body and dimension to the stock Pro-Ject DAC which, on its own, while not bad, IS thin sounding!
I am just about caught up with backorders for the new KWH 225i and then I will dive head first into the buffer project. It is the perfect time for it!
Thanks guys...just kidding about the $5K price. $4995 at the MOST! 8)
Dan
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Hi Dan! Funny I've just sent you an email about the buffer.
From my perspective I thought I'd need something simple but because nothing stay simple long enough in my setup I would need more I/O.
2 XLR inputs, one RCA input and one XLR output.
This for: Modwright BDP83SE (you know the one) still running, LKS MH-DA004, Sony TA-ZH1ES => Denon AVP-A1HD Cinemike XLR unique input.
It would help group all source in the XLR input on the Denon.
Do you think this is doable ?
Also funny you say you got tired of the squeeze box. I listened to a Kennerton Thror at a friend's using a Squeeze (not Modwright). Nice Auris DAC and amp. I found the sound a bit arsh.
Not how I listened to Thror before.
Got myself a B-Stock Thror. My friend came to my house to give it a try : custom mod PC with SOtM cards, modded PSU, damping, filters, some Audio Magic stuff, OPPO HA-1 SE (Audiocom modded plus extras), TRYST (of course), not the same same headphone at all.
We concluded that the Squeeze is not good enough anymore and replaced it by another kind of setup based on ROON and pc sources. The Squeeze was indeed the weak link.
Have you ever considered using a tweaked PC with Audirvana (you have a two station licence I sent you) or JRiver?
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Still interested in replacing my dac digital volume control with this! Hope everything is going well at modwright and your 225 integrated is selling like hot cakes
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It is still inline. It has just been an unusual year!
I am working on it!
Thanks,
Dan
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If I end up with a solid state pre-amp + amp, I'll want one of these in between.
cool
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It has not been forgotten. It is a crazy year and we are strong and busy, but my time table is way off for a number of reasons.
Thanks,
Dan
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OK guys, it is time to resume this thread and bring this product to the finish line!
First of all, it has been a strange year plus, for all of us! For me personally, I got off track, and I feel now like I am back! Like many of you, a lot of introspection, time alone and such a change in lifestyle. I don't really feel like the same person that I was before 2020. Not all for the bad, many ways for the better. But, all the same, I kind of got knocked off course.
I have been focusing on the KWH 225i Hybrid integrated amp and the PH 9.0 tube phono and PH 9.0X upgraded version. These products are doing well and I am now feeling inspired to take (code name: 'The Buffer') to market. Product name is much cooler, but that will come later!
While I have asked what everyone wants, and weighed it all, I have decided to do the following:
The initial product will be as follows:
RCA in and RCA out.
< $995.
No volume control, no remote.
Compact enclosure with exposed tubes.
Likely tube rectified.
High bandwidth, low distortion, low noise and very low output impedance to match with ANY amp, tube or SS!
Lastly, I have an idea for tube rolling and flexibility of tone and preference, that I believe will be well received!
The whole intent of this design was to take the 'mod' out of the the digital source and make this a product that can be used in any system with any analog signal device. I.e. between DAC and amp, DAC and preamp, any other source analog signal path in, out to amp/preamp. Many of you have SS systems and want to add tubes, but don't want the hassle of biasing a tube amp or are uncertain about going to a tube preamp. Many of you also have digital sources with built in volume control that drive amps directly. This product can add 'the tube sound' to your system, without adding noise, and will also offer your amp the VERY low output impedance that it wants, to perform its best! No passive volume control and offer the impedance matching of an active circuit such as an active preamp or buffer.
Next step is to get the rubber on the road and design the enclosure and finalize the circuit.
I will share progress and images of the project here and I hope that you will share your frank feedback.
This project began some time ago and I know many of you thought it had died on the vine, but rather, it has simply matured...
I am ready for an exciting new product that is affordable, flexible and will fit ANY system!
Thank you all for your support, feedback and patience!
Dan Wright
CEO, ModWright instruments Inc.
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Dan - there are some dacs out there with a volume control, but often they are poorly implemented (either volume reduction in digital domain with attendant bit-stripping, or cheap non-remote pot mounted on front panel)... I think having your tube buffer with proper remote volume (bypassable with a toggle) would be a winner.
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I think he's trying to keep the cost and complexity down, which makes total sense to me. I would like to see an option for dual outputs though. Perhaps this is easy enough and can be added at time of order?
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what is old is new again
https://audiophillness.com/musical-fidelity-x-10v3/
https://www.ebay.com/itm/393245210072?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=393245210072&targetid=1068323855710&device=c&mktype=pla&googleloc=9032105&poi=&campaignid=11612432082&mkgroupid=113994509995&rlsatarget=pla-1068323855710&abcId=9300456&merchantid=6296724&gclid=Cj0KCQjwyZmEBhCpARIsALIzmnJ25PB3tmwr_6cGgfhaEx-VaGiyNTgkFnatQa8NMCXL0Vu4CEl0sG8aAiEBEALw_wcB
https://www.ebay.com/itm/203326034453?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=203326034453&targetid=1068323850950&device=c&mktype=pla&googleloc=9032105&poi=&campaignid=11612431611&mkgroupid=120003497904&rlsatarget=aud-622027676548:pla-1068323850950&abcId=9300456&merchantid=112050702&gclid=Cj0KCQjwyZmEBhCpARIsALIzmnJCWikijPbf7Cuw1yzFEZn3N69_ehL1mqy3auQ_UlySF8er0Zer4HcaAkIcEALw_wcB
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Not really sure what the point of your post is jjss49, especially posting eBay advertisements. There are indeed many crappy, low quality, tube buffers out there that can be bought for a few hundred bucks. Lots of choices from China. If that's your cup-o-tea have at it. They won't be as well built nor perform as well as Modwright.
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rdavidson, why are you so offended and what do you know about what is my cup of tea?
my point is on the first line of my post - what is old is new again -- if what dan proposes is a tube buffer with no volume control, one set of rca inputs one set of rca outputs
the musical fidelity buffers were good in their day, they were not crap, just as musical fidelity is not crap today, conceived and brought to market by antony michaelson in the uk (some of this mf 'crap' has even been stereophile class 'A' gear) :) ... they enhanced many a system that needed the same help that dan's proposed unit will bring, solving the same problem... a leaned-out sound from digital sources due to a lack of a good, properly impedance matched output stage, plus sonic beautification from small signal tubes
the MF X10 v3 in 2004 was MSRP $400, makes it just short of $800 in 2021 dollars
i am a fan of dan's... have owned 5 of his preamps/amps and modded cdp's over the years, still have 2 of them, both bought direct... i am just suggesting he try to do something more distinctive if he is going to work on a new product, as busy as he is
he is here seeking honest input in this public forum, and this is mine, from an actual paying customer
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The initial product will be as follows:
RCA in and RCA out.
< $995.
No volume control, no remote.
Compact enclosure with exposed tubes.
dWright instruments Inc.[/size]
Balanced in/out option available?
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What do you guys think of the following, in lieu of a full tube mod to a digital source?
Tube Buffer with volume control, ideally remote control.
Two inputs: Simple system with say vinyl and digital source.
Zero gain, low output imepdance for matching with any SS or tube amp.
Low Noise, Low distortion.
Goal: Act as a preamp/passive preamp or volume control while adding BUFFERING, which is the most important part of any preamp!
Mulitple source input and R/C volume act as preamp functions, but without unwanted complexity, circuitry and cost.
This would add tube tone to any system, SS or otherwise.
It would improve the sound of less than stellar digital sources.
Can be used with different digital sources.
Also, being as how it is unity gain, would also integrate into a HT system without the need for a bypass.
Form factor would be medium size, one box.
Finish would be classic ModWright: Elegant, clean and sophisticated.
Cost: $995 as a starting point.
Input welcome!
Thanks,
Dan
This would be what I'm seeking. Volume, even without remote needed. I could live with 1 input and no selector switch. As long as the output impedance was low, I could use a "Y" jack on the output.
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OK guys, it is time to resume this thread and bring this product to the finish line!
First of all, it has been a strange year plus, for all of us! For me personally, I got off track, and I feel now like I am back! Like many of you, a lot of introspection, time alone and such a change in lifestyle. I don't really feel like the same person that I was before 2020. Not all for the bad, many ways for the better. But, all the same, I kind of got knocked off course.
I have been focusing on the KWH 225i Hybrid integrated amp and the PH 9.0 tube phono and PH 9.0X upgraded version. These products are doing well and I am now feeling inspired to take (code name: 'The Buffer') to market. Product name is much cooler, but that will come later!
While I have asked what everyone wants, and weighed it all, I have decided to do the following:
The initial product will be as follows:
RCA in and RCA out.
< $995.
No volume control, no remote.
Compact enclosure with exposed tubes.
Likely tube rectified.
High bandwidth, low distortion, low noise and very low output impedance to match with ANY amp, tube or SS!
Lastly, I have an idea for tube rolling and flexibility of tone and preference, that I believe will be well received!
The whole intent of this design was to take the 'mod' out of the the digital source and make this a product that can be used in any system with any analog signal device. I.e. between DAC and amp, DAC and preamp, any other source analog signal path in, out to amp/preamp. Many of you have SS systems and want to add tubes, but don't want the hassle of biasing a tube amp or are uncertain about going to a tube preamp. Many of you also have digital sources with built in volume control that drive amps directly. This product can add 'the tube sound' to your system, without adding noise, and will also offer your amp the VERY low output impedance that it wants, to perform its best! No passive volume control and offer the impedance matching of an active circuit such as an active preamp or buffer.
Next step is to get the rubber on the road and design the enclosure and finalize the circuit.
I will share progress and images of the project here and I hope that you will share your frank feedback.
This project began some time ago and I know many of you thought it had died on the vine, but rather, it has simply matured...
I am ready for an exciting new product that is affordable, flexible and will fit ANY system!
Thank you all for your support, feedback and patience!
Dan Wright
CEO, ModWright instruments Inc.
Hi Dan - been watching this thread for a while but in the interim, two weeks ago, I sprung for an Oppo 205 ($2,750 :roll:) I spoke to Kristen about adding an analog input to the 205 as part of your 205 mod. She explained, in great detail why that could not be done (hope you're paying her the big bucks, IMHO she deserves it). Since it can't be done, and I've already paid through the roof for my 205 (but very happy) the "Buffer" would be an economical substitute for the full 205 mod.
But I'm back to the same issue, I need an analog input for my TT. I don't need a volume control as the 205 has a very well thought out digital volume control. And I don't want to purchase a preamp; the whole point of the 205 driving my monoblocks directly. So I like what you're proposing, just need two inputs (and I guess a volume control for the TT input).
Thanks for all your great work, Kristen too. :D
Russ on Long Island
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I completely understand your desire to start simple and go from there, but let me just say that was caught my attention was a tube buffer with remote-controlled volume control and RCA and XLR in and out, i.e. the full Monty. Perhaps it could be modular, with those offered as add-on options.
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Hi guys, the intent is to make the product modular. The initial offering will be RCA in and out only.
Balanced inputs and outputs would be expensive as the ideal way to do this would be with transformer coupling. It can be done as an add cost offering.
RE R/C VC, that too could be done, but my intent was to offer a product to integrate into a system that already contained a VC as most digital sources do these days. It would pretty much be a unity gain preamp as described. Having said that, with the modular approach, this could be done too.
Yes, the 205 only offers a tube analog OUTPUT stage, but this tube buffer could work with ANY source!
I think you will like my idea when you see the final design. It will allow for A LOT of flexibility in terms of tailoring the sound! I will also make the fuse(s) easily accessible via external port for those who like to upgrade their fuses.
Thanks! More soon!
Dan
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OK, I can see the desire for a VC. I am trying to keep the complexity down as well as cost. I envision a box with a single knob in the middle for power and on/off and the selections that I intend to offer. Mulitple inputs would not be difficult. This could be achieved with a simple toggle or push button to toggle through relay selected inputs.
Adding a GOOD VC is expensive and not really fitting this products price-point or intent. I am aware that many DACs use bit dropping VC's, but you also need to consider that most new DACs are also 32 bit. With most all data being 24 bit, they are still truly non-decimating VC's.
Sure, a R/C stepper would be great, but the cost of that alone could exceed $1K! My expectation is that the customer will either have a built in VC in their source or a really good passive attenuator upstream of this product.
As for what is old being new again...yes and no. There are many cheap buffers on ebay and Amazon from China. Most are high distortion designs that are intended to add tube distortion. The circuit I am using is very low distortion and wide bandwidth, so while the tube character is there, it is not due to high amounts of tube distortion. The product I have in mind will be versatile and offer the user different options to tailor the tone of their system.
Thanks,
Dan
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if you are making it dan, no one who has been your customer will doubt its voicing or its production quality
so comparing to cheapo hyper coloured chinese ones isn't part of the consideration
the musical fidelity pieces are not that though, but certainly, anyone who knows gear would not expect them to sound as nice as what you would make in the modern day
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jjss49, I was only offended that you posted advertisements for old, low priced, crappy, "competitors." I thought this was in poor taste. I am very aware of what Musical Fidelity has put out on the market over the years. Many of us here are aware. So your post with the advertisements came across as a jab at Modwright...like, why pay $1k for a simple tube buffer when that has been done and can be had for far less $? With your further explanation, I understand your intent was not malicious now, but surely you can look back and see how your post came across poorly, right? There's TONS of info written and available online about these old, lesser, buffers from MF and China, so why choose to share eBay ads to make your point? That's all I'm saying.
2 outputs on the buffer would be a great, and I think a simple, low cost, option. 1 output to the main amplifier and 1 output for a subwoofer or two (left and right). That'd be SUPER handy for folks using their DAC for preamp duties.
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OK, I can see the desire for a VC. I am trying to keep the complexity down as well as cost. I envision a box with a single knob in the middle for power and on/off and the selections that I intend to offer......
....Adding a GOOD VC is expensive and not really fitting this products price-point or intent. I am aware that many DACs use bit dropping VC's, but you also need to consider that most new DACs are also 32 bit. With most all data being 24 bit, they are still truly non-decimating VC's.
Sure, a R/C stepper would be great, but the cost of that alone could exceed $1K! My expectation is that the customer will either have a built in VC in their source or a really good passive attenuator upstream of this product...
Thanks,
Dan
Completely understand. I have several high quality dacs (Lampizator, Chord, Aqua) none of which have volume control. In one system I'm currently using an LTA Microzotl, which is very similar to what you originally suggested building (tube buffer with volume). It has high input impedance and <2ohms output impedance, allows significant tube rolling, is dead quiet, and can drive multiple amplifiers effortlessly. But, it has gain. 6db in it's lowest configuration, and I'd like zero gain for high efficiency speakers. I do think there would be more interest if your buffer had volume, even if optional, and perhaps even at price points of VC choices. Don't want to beat a dead horse though. Appreciate your interest in members opinions. :D
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Thank you all for your support. I realize that when it comes to a 'tube buffer', there is really nothing of quality on the market and most are the same basic circuit that anyone can make. I have something different and better in mind, obviously.
I want to keep it simple and < $995. It will be sold direct, not through dealers, so the value will be high!
RE VC, it isn't that it would add significantly to the cost, but it would be a volume pot, not a stepper or autoformer based control, etc., as the budget will simply not allow. Having said that, I have access to good and not expensive volume pots that could be designed in, with a bypass.
RE XLR inputs and outputs, there are two ways to do this and both add some cost. If I use transformers, it will add a non-trivial cost. Good transformers are not cheap! I could also design it to be fully differential and this would mean four tubes instead of two. This is the lesser cost way to go. There is even the possibility of designing it in such a way that tubes LA and LB, RA and RB could allow for some mixing and matching of tubes for different sound. I.e. not requiring a matched quad, but rather two matched pairs. One could be warm and sweet, the other fast. It would be a way to adjust the sound and tone.
'Tone Adjust' is a key feature of this design to me. I DON'T mean that it will have tone controls, nor will it have gain. Lastly, no feedback. Feedback and tone controls (traditional) would all require gain. I also don't like to use either FB or tone controls. Rather, with different tubes and perhaps different circuit implementation that is adjustable on the fly, the customer could adjust the tone of the product to suit their ears. I have already shared one way that this could be done.
I think the tube rectifier is key as it also allows a further 'tone tuning'. To be clear, 'tone tuning' does not equate to added distortion or reduced bandwidth!
I think that adding say two inputs and two pairs of outputs could be implemented in the base model as I can see the benefit of this. Perhaps XLR and RCA outs, where the XLR outs are fully balanced? Also fully balanced inputs and RCA inputs. I need to know how many people want balanced inputs and outputs.
My plan for this product is for it to be as simple to use as a connect and forget, setup, but adjustable to allow people to taylor the sound to their tastes also, if they choose. I also don't want any dip switches or anything that requires taking the cover off. I plan for tubes to be fully exposed and the front panel controls to be simple and 'on-the-fly' as our PH 9.0 and PH 150 phono stages are.
Aesthetically, it will be clean and physically slim. I don't know that it will be full 17"W and I would prefer to keep the enclosure height to close to 3"H. It could be set directly on top of a digital or analog source, provided it doesn't need to reject heat. I don't typically recommend this from a noise standpoint, but in this case, if there are not signal transformers used, it could be done. Tubes will be on top and exposed, so all heat will be rejected up and out of the unit.
I would like to see a simple faceplate with one knob in the center, for power on/off and input select. Perhaps one or two other buttons for other features, but ideally clean, simple and uncluttered. This is not a preamp, not a professional mixing device with knobs and switches to adjust. It is meant to be clean, simple and easy to use, but still allow flexibility for the user who wants to experiment with different 'tone'.
Thanks guys, this product is long overdue and the design has left the station!
Dan
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Who wants to be able to use 2-3 different families of tubes in the unit?
Thanks,
Dan
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:wave:
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I love this concept Dan! I own the LX500 that you modded but would love to have a tube buffer for my RME ADI FS DAC. Everything you do brings that tube magic. For me I was never able to get the 225i on my budget but this will bring me closer to tube heaven. So happy to see more affordable solutions! Thank you Dan
René
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Right on, thanks!
Volume control?
Multiple tube option?
XLR and RCA?
Dan
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For me volume not necessary, it’s a buffer not a preamp sooo IMHO.
Multiple Tube Option -Definitely
XLR-RCA - Definitely
Again great innovation and definitely will fill a void.
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Thank you! The VC is still something I am working through. I think that people want it to be a preamp and that is not the intent.
As to XLR and RCA in's and outs, it is a matter of more tubes or transformer coupling.
Thanks!
Dan
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Sounds like one input only, is that correct?
If so, having two sources (DAC and turntable), is there a way to hook up this buffer to my KWI 200 and utilize it for both ?
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I think that two inputs would be a good thing, as well as two outputs. That is easy.
As for XLR inputs and outputs, that is a decision that requires more complex design and added cost.
Thanks,
Dan
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Hi Dan
IMO real balanced can also be used as a real SE.
The use of transformers is an OK solution but defeat real balanced design.
Yes I'd need XLR and real balanced (2 pair of tubes) as I would use the buffer in a real balanced path.
From DAC to amps.
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Use of transformers is "real balanced."
What you're referring to is dual differential balanced, which is double the circuitry and ~double the $. Dual differential is not some sort of panacea at the end of the day either. In fact it can introduce other issues.
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Hey Dan,
I know this isn't highest priority, but I hope you are still working on this.
On memorial day I picked up a Tube PreAmp. Man oh Man!! I spent decades listening to solid state only. I was missing out. I'm never going back to a tubeless system if I can help it. I even ordered a integrated tube setup for the home office.
This is the kinda product that would really be transformational to those with run all sold state. So please keep plugging away! I think this product could really spread some audio joy! :thumb:
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Hi guys, finally caught up and back on this design!
Putting pen to paper and laying out PCBs to decide on options.
Base model will be a VERY wide BW, very low THD (< .003%) buffer.
Stock design will likely have 2 inputs and a toggle to select between them.
Tube type: 6922.
Now for options:
1. Balanced inputs and outputs. I have to disagree that transformer coupling is not a true balanced design. Pro Audio has been using line matching transformers forever and they are the ideal way to couple signals! Using 2 x the tubes for a 'true balanced' design means that you have twice the circuitry and twice the tubes to match. I believe there is the misconception that a transformer is 'adding' something to the signal path that will only color the sound. Experience has taught me that transformer coupling IMPROVES the sound, by nature of how it handles signal.
So, what I am saying is that the balanced option will be transformer coupled in to out. This means that a balanced input signal will see a balanced load and the output will be fully balanced. There will be no SE wired XLR's.
2. Volume control w/remote is the other option. This will require a PIC and controls and will likely use an Alps motorized VC or similar. I know that there are better volume controls out there, but including them would drive the price of this product up too high. Plus, there are so many options that I would be asked to use custom and specific steppers, etc. and this product does not lend itself to this. This is not a modification product, but a production product. In order to keep prices reasonable, I have to standardize some things.
3. I am looking to offer a way to customize the sound. Offering different tube options is one way, but often this means that the design is not really optimized for any one of the tubes, but compromised to allow all of them to operate. The other way to go would be to use a pair of 9-pin sockets and a pair of Octal sockets, each biased specifically for a different tube. I am thinking 6922 and 6SN7. Each would be a separate circuit with its own specific bias, etc. The other way to go would be to offer the same tube but different bias points. Different bias for a tube can add warmth or detail and allow for a way to change the tone of the sound.
4. I will review this thread to see what other options we discussed.
Thanks,
Dan Wright
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Sounds like a useful product. I would prefer the 6SN7 tubes. Also, what about tone controls that you can bypass?
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OK, I just reviewed the entire thread...I am embarrassed that this started in 2018 and it has been so long. So much has happened since then! I'm glad my son and I made the trip to Europe in 2019, because we all pretty much burned the calendar in 2020! Anyhow, I am still very much moving ahead with this product and now I have the time and momentum to take it to the finish line!
The options that I feel should be included in the base model:
1. Two RCA inputs, toggle to select.
2. Two pairs of RCA outputs, to allow connection to amp and SW's.
3. When powered off, it will default to a bypass mode. I.e. if you don't want it on when watching movies or whatever, just power it off and the unit will act as a straight wire bypass.
4. I think that 9-pin and octal sockets to allow two different and fully optimized tube types is the way to go. Rather than bias one tube circuit for multiple tubes, I will simply have two sets of sockets, each optimized for its own tube. Likely 6922 (9-pin) and 6SN7 (Octal).
5. I am not sure about tube rectification. This may be a add-cost option.
6. Volume control will be an add cost option that can be bypassed.
7. Volume control option will include remote: Power, mute, input select and volume.
8. Balanced inputs and outputs will be an add-cost option, including four Lundahl transformers for input and output coupling for truly balanced inputs and outputs.
I think this about covers it!
I am looking at a modular design, that will allow you to add the upgrade options and install them easily yourself. This will not be hard for the balanced option. The R/C volume option may be a bit more tricky. Perhaps we offer it from the factory w/or without VC. This would involve several changes.
Another thought on the subject of volume control! We could offer remote power, mute and input select. Those of you who want the best possible attenuator, could then use a separate passive attenuator. There area number of very good and custom designs available. It could sit beside the Analog Bridge and connect via short interconnects. This is the solution for those who want the BEST attenuator and the best buffer!
I will share images of the front and rear layout and overall chassis design soon.
Thanks!
Dan Wright
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I have decided the following:
I am going to forego the volume control entirely. Not even as an option. Those who want a high quality VC, can use a high end stepper or other passive.
There will be no tone controls. The 'tone control' if you will, will be the choice of 6SN7 vs. 6922 and tube rolling. Because, these two tube families have a different tone.
I have also decided there will be no R/C at all. The design will be kept simple, and as something that can be added to any system, not as a preamp replacement.
XLR inputs and outputs may be standard, but wired SE. As an add cost option, there will be a user-installable PCB with four expensive Lundahl transformers to fully couple inputs and outputs for fully balanced I/O.
Front panel controls will be simple, clean and symmetrical:
Power, Mute -- Tube Select and input as four small buttons, two left and two right.
Center will be MWI logo and graphics.
Tubes will be exposed through lid for easy tube swapping.
Tube rectification may be standard.
HT/BP will be integral with the unit defaulting to bypass when turned off.
At this point, the overall dim's of the unit look to be: 10"W x 3.5"H x 12"D.
That is where I am at now. It is decision time and I am moving forward!
Thanks,
Dan W.
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Hi Dan, if tube rectified does that mean the power supply will be linear and not a switching supply? Will the power supply be external?
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Good choice to keep it as simple as possible Dan. It will keep the price down and probably sell better.
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That is the intent. This product needs to be market specific, VERY good and priced reasonably.
Thanks,
Dan
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FWIW Specs:
The optimized 6922 circuit measures as follows:
Frequency response: Flat 20Hz - 100Khz
Noise: -110dB
THD: < .003%
Thanks,
Dan
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Hi Dan,
Your description make sense for a simple and well executed design.
Just so I can understand how the HT bypass will be implemented, would one of the inputs be connected to the HT processor outputs, so if the buffer is turned off the HT processor is routed to the output of the buffer? If so would a preamp be connected to the other input so if the buffer is turned on then the preamp can be ran through the active circuit? Would the input selector need to be set to the HT input for the bypass to work when the buffer is turned off?
Thanks,
Greg
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RE HTBP, the intent would be, that either the last input used or a fixed input used, would be the default input when the unit is powered off. Normally Closed (NC) relays would default to a bypass configuration when the unit is powered off, as a straight wire bypass. There may not be a bypass button, rather, just the fact that you power it off. This is the most elegant way to handle it.
Because there is no volume control, the volume would be entirely dependent on the VC in your source, preamp or integrated amp as when you normally use it. There is no danger of risking high outputs because the design does not attenuate the signal when operating.
Thanks,
Dan
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Another option that I considered at the onset of this product, was to include a modular linear power supply, to power the DAC that the unit is connected to.
I used the inexpensive Pro-Ject DAC to design the prototype. It relied on a wallwart for 5VDC supply to power the DAC. The DAC did amazing things in a compact package, but a phone charger as supply was not ideal! I built a dedicated 5V DC linear supply into the prototype to power the Pro-Ject DAC and also of course fed the signal into the tube buffer stage. The combination of power supply and tube buffer were nothing short of incredible in terms of the boost in performance.
Now, some DACs have good supplies, some use wall warts and they operate from different voltages.
The digital LPS supply design would be modular and could be designed for different voltages: 5V, 8V, 9V, 12VDC, etc.
The other thing to consider is what the power connector type is on different DACs.-
If this option interests you, please tell me which DACs, what voltages and what the power connector type is.
I envision a PCB that could be user installable and a port on the back of the unit with cover plate unless the option is ordered. You would have to order the supply with the right voltage and specify power connector type. I can envision a standard connector on the end of our product, that is perhaps custom on the other end, provided there are only a handful of different connectors used. I think most use a simple mini-jack 2-conductor design.
Thanks,
Dan
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I just stumbled across this thread and am very interested to see what product comes out of it. I have used a Bent Audio AVC-1 for years with a horn/SET system but recently reconfigured to Spatial Audio X3/SS amp and am thinking about how to reintroduce some tubes into the system.
My initial thought was a tube preamp but I really don't need gain. I'm already at the low end of the VC with the X3s.
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Your situation is exactly the need that I am trying to meet!
Adding tubes in the right (Wright?) way! Very low distortion, low noise and wide bandwidth. We are adding the holography and 3-D soundstage of tubes without the overly warm distortion and poor frequency response of common tube buffer designs.
Please stay tuned as I will be wanting Beta testers when we make the first short run.
Thanks,
Dan
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Dan,
Clean power is a godsend. People underestimate what results it can yield. Your unit having a flexible and clean power supply for itself and to "rescue" other components, only adds value. Having it as an option, even better. Someone can get in the door first and then come back later when funds permit to upgrade the power supply.
Do it! please :D
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I will certainly add the option.
My intent with this product is for it to be versatile, high value and allow an attractive and highly productive upgrade path.
Thanks,
Dan
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I might as well just give you my VISA card now :)
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It sounds like this product is in demand? 😁
Thank you! I am moving full speed ahead on this.
I am currently working out the 6922 and 6SN7 tube option circuit and layout. Work is going well!
Thanks,
Dan
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Hi Dan
I am very interested as well.
Do you have an eta for this project?
Stefan
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HI Stefan and all of you that have been patiently following this thread. I am well into the design at this point and hope to have it out by the end of Q1 this year.
Thanks and Happy New Year Everyone!
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HI Stefan and all of you that have been patiently following this thread. I am well into the design at this point and hope to have it out by the end of Q1 this year.
Thanks and Happy New Year Everyone!
:thumb:
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Very interested to mate this up with Wyred4Sound Class D mono units - I miss a little tube distortion:)
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OK guys, much overdue update on the Analog Bridge product!
MSRP is estimated to be < $3K. ($1K add for fully balanced inputs and outputs via Lundahl signal transformer coupling).
Note: These proto chassis are bare steel and oxidize quickly. Finishe products will have black powdercoat chassis and cover and face plates will be either silver or black. Toggles will be silver.
(https://www.audiocircle.com/image.php?id=242228)
(https://www.audiocircle.com/image.php?id=242229)
(https://www.audiocircle.com/image.php?id=242231)
First of all, I have a prototype built and working. I am adjusting this and that and listening. I can say that it works VERY well and sounds fantastic! THD < .005%, Noise below -105dB and BW flat to nearly 200Khz.
These are the functions and decisions made about the final design:
Front display will have four toggles (not buttons): Power, Mute - Input Select, Tube select.
There are two RCA inputs and two RCA outputs. XLR add cost option will add a single pair of XLR inputs and outputs and a rear toggle to switch between XLR and RCA use.
No remote control.
No volume control.
No bypass.
No PICs, processors or other noisy digital processors with high frequency clocks to add noise. Pure analog logic controls.
Tube rectified: Can use any 5AR4 and compatible tube such as: 5U4G/GB, 5R4GY, 274B...
Driver tubes - selectable on-the-fly: 6922 or 6SN7 (CV181 and compatible).
So, the beauty of all of this is that you have A LOT of ways to 'tune' the system. Rolling rectifier tubes makes a big difference. 6922 and 6SN7 tube families have very different sonic profiles. Plus, rolling different 6922's or 6SN7's will further change the sound to your taste.
Because the distortion figures are so low, you ARE getting tube sound, but not because of large amounts of 'warm' tube distortion.
There is similarly no loss in bandwidth, with frequency response flat to nearly 200Khz.
Lastly, the output impedance is ridiculously low at about 20 ohms. It will thus drive any amplifier.
I am calling it the 'Analog Bridge' because that is what it is. As counterpart to a 'Digital Bridge' which interface dgiital data between server and DAC, the analog bridge interfaces in the following configurations:
Between Digital source and amp (assuming source has volume control).
Between Digital source and preamp.
Between any source and integrated amp or preamp.
Between preamp and amp (if all SS system, this will add tube character to the sytem and provide ideal impedance matching to any amp).
Between passive pre or passive attenuator and amp (here most critically allowing for the most ideal impedance matching between attenuator and amp).
The analog bridge is a system Accesssory. As such, it does not replace your preamp, although if your source has a volume control, it could take the place of a preamp. It can be added to any system to improve soundstage and 3-D imaging by bringing the character that only tubes provide, without adding the normal distortion and bandwidth limitations commonly attributed to tube products.
The chasssis dimensions are: 10"W x 13"D x 3"H. Tubes are exposed, which makes actual height taller, depending on tubes used.
I have also made provisions for an internal regulated DC voltage regulator to provide a clean LPS (linear power supply) voltage to power an outboard DAC that relies on a wall wart or outboard DC supply of poor quality. I have not priced this option yet, but it will not be very expensive. I have to work out which DACs it could serve and how to handle the DC cable from the Bridge to the DAC as well as the specific connectors needed at the input of the different DACs. I expect a simple umbilical with a universal connector on the end that will accept adaptors to suit different connectors.
Currently this circuit is part of the power supply PCB. I may make it a socketed upgrade so the module can be user installed with a user installable cable to connector and cable.
So there you have it, Progress!
I welcome any and all comments and input/feedback.
If you are interested in being on the list to contact when in production, please let me know!
Thanks,
Dan W.
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I think I’m already on the list, I received Kristin’s email about these new details recently, but if not I’d like to be added.
If wanting to add tubes to my system, to be used with the KWI 200, am I better to go with the KWI 225 instead of the KWI-200/Analog Bridge combo?
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Dan,
By any chance, will you have a working model at Pacific Audio Fest at the end of this month? What other goodies do you plan to have there?
Michael
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$3000 for something you probably don’t need? Uhh, no thanks.
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I will have a working model at PAF, yes.
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A working model at PAF…… and i can’t make it down from Vancouver BC that weekend, sigh.
There are so many things I want to see/hear and people to meet.
Missing it will be torture.
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Hi Dan,
So with 6SN7's would this sound similar to an LS100 with no volume control?
Thanks!
Dave
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It is a very different circuit, but yes, the sound will be very similar and the measurements even better!
Thanks,
Dan
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I wanted to give an explanation for the price increase over that which was indicated in 2019 when I first started this thread.
I had said that I was shooting for a price point of < $1K. It was also intended to be a direct-sale model only, but I have decided to offer it through dealers. The MSRP is now to be < $3K.
I first started thinking about this in 2019 and it was intended to fill the space left when Oppo closed their doors and they were hard to get.
The thought was to have a tube mod that was external and could be used with any digital product. My goal was for it to be simple and inexpensive. The first proto I built was simple and the cost appeared like it would be low. I was also going to sell it only direct. This proto used a hammond transformer, extruded AL project box, a simple supply and a single pari of 6922's that were inexpensive at the time.
It is now 2022, EVERYTHING has increased in cost. I have decided that it will be available to dealers also. I decided to add tube rectification and the ability to use two families of tubes. Tubes have skyrocketed in price. When I added up the Bill of Materials at todays pricing, I realized that the cost would have to be about $3K. The balanced option requires the use of four Lundahl Swedish transformers which are very expensive.
All of our products increased in price at the start of this year by 15%-30% because of all increased costs. The fact that dealers are to be included in the sale of this product also, means it is higher priced yet.
If I was a direct-sale only business model, I would price it lower and it would not be an issue. The conflict has always been that our mods are sold direct and our own products through dealers. Having said that, our Oppo 205 mod was $2500 direct and with upgrade options, easily exceeded $3K.
At the end of the day, I have to make a profit or go out of business. I designed this product with cost in mind, but also intending to offer the best possible performance and value as possible. The enclosure was kept simple, like the PH 9.0/9.0X phono stages. In that product I was able to spend the majority of the budget on quality parts and design.
It was not my intent to mislead anyone and I understand that some will find that this product does not suit their budget.
In the end, I wanted to make a great product!
Sincerely,
Dan Wright
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I wanted to give an explanation for the price increase over that which was indicated in 2019 when I first started this thread.
I had said that I was shooting for a price point of < $1K. It was also intended to be a direct-sale model only, but I have decided to offer it through dealers. The MSRP is now to be < $3K.
I first started thinking about this in 2019 and it was intended to fill the space left when Oppo closed their doors and they were hard to get.
The thought was to have a tube mod that was external and could be used with any digital product. My goal was for it to be simple and inexpensive. The first proto I built was simple and the cost appeared like it would be low. I was also going to sell it only direct. This proto used a hammond transformer, extruded AL project box, a simple supply and a single pari of 6922's that were cheap.
It is now 2022, EVERYTHING has increased in cost. I have decided that it will be available to dealers also. I decided to add tube rectification and the ability to use two families of tubes. Tubes have skyrocketed in price. When I added up the Bill of Materials at todays pricing, I realized that the cost would have to be about $3K. The balanced option requires the use of four Lundahl Swedish transformers which are very expensive.
All of our products increased in price at the start of this year by 15%-30% because of all increased costs. The fact that dealers are to be included in the sale of this product also, means it is higher priced yet.
If I was a direct-sale only business model, I would price it lower and it would not be an issue. The conflict has always been that our mods are sold direct and our own products through dealers. Having said that, our Oppo 205 mod was $2500 direct and with upgrade options, easily exceeded $3K.
At the end of the day, I have to make a profit or go out of business. I designed this product as cheaply inexpensive as possible, whilst still achieving the desired design goals.
It was not my intent to mislead anyone and I understand that many will not be interested at this price.
Sincerely,
Dan Wright
You do good work, Dan. Now it's fixed. ;)
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Thanks!
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Hi Dan,
You offer the best quality product you can at a price point that allows you stay in business. I have no doubts it will perform admirably.
In your final design you were not able to do HT pass through?
Greg
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I did not include a HT bypass in the final design.
I amy consider this however, for the final production, as I am thinking that it might be nice to be able to bypass the buffer directly, for a number of reasons.
Thanks,
Dan
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Curious, how was the interest and response to the Analog Bridge at the Pacific Audio Fest last weekend.
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It was very well received and we had great sound overall. I was able to A/B the system with and without the Analog Bridge, fed from a Mytek Liberty DAC. It showed itself well!
Great show coverage from Jason Victor Serinus.
https://www.stereophile.com/content/modwright-debuts-its-analog-bridge (https://www.stereophile.com/content/modwright-debuts-its-analog-bridge)
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OK guys, I know that I have not been posting much here lately and for that I apologize. This thread was started a LONG time ago and the birthing process for this product has been epic. It has evolved from the first inklings I had about this design, pre pandemic. I took all of the input from those who took time to reply and the result is finally a reality.
I realize that at a $2900 starting price, it is more expensive than the original concept. I would also ask you all to consider the time that has passed, the effects of inflation and the fact that the final design is much more sophisitacated and higher performance than the initial prototype.
We have finished the first production run and I have feedback from our first Beta customers and dealers. Dealers have told me with confidence that it IS a product that they can sell! Following is some of the first feedback we have received and I will post more as it comes.
If you are interested, we still have a few units left from the first production run, and the next production run is under way.
(https://www.audiocircle.com/image.php?id=249671)
Feedback:
Equipment: Lumim T2 dac / streamer or Anthem avm 60. To Analog Bridge. Innersound DPR-500.
I have tried a few different rectifiers. Every time i get a better rectifier, the level of everything as a whole is brought up, clarity, detail, space, imaging, depths, separation, and weight.
The Analog Bridge has improved everything. From the bass clarity improvement to the richness of vocals and the taming of harsh digital treble, its all there.
I mainly listen to hip hop, R&B and lots of various electronic music. I tested it with lots of tv and movies as well. All performances improved. It really doesn't matter what it plays. It just works on whatever you feed it. – Dana – 2.2023
Equipment: Sonnet Hermes DSD >I2S connection > Sonnet Morpheus DAC > Balanced XLRs to ModWright Buffer > Balanced XLRs to Cary Audio 200.2ES SS Amplifier > KEF R3 speakers.
I find the buffer enjoyable and to add a tube dimension that is appealing.
I feel as though the MW analog bridge has added a level of musical note decay that I find appealing. It does not seem to have reduced the dynamic range of my system or compressed it in any way.
I listen to several different genres of music - primarily softer rock, jazz, and some blue grass. I find vocals to be expressive and emotional with the unit (like most good tube gear). So has it improved my overall system...
I think for anyone looking to add some of the instrument separation/space, emotional uplift, and enhanced note decay - this unit is a good choice. It also gives a lot of flexibility to the listener to switch between systems and to switch sound character. – J. Kenyon, 2.2023
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Finally had a chance to meet Dan Wright and hear the Analog Bridge this weekend at the Pacific Audio Fest in Seattle.
Dan switched between 2 types of tubes (not sure which) on the fly and the difference was significant.
Both good, but different.
Had to pass on this as a beta tester last year but now that I’ve experienced it in the flesh, I see this device in my future.
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great that it finally is being released!
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Yes, very much in production now and very well received, in use with Weiss $2895 DAC at PAF. I found that the 6SN7 circuit in the Analog Bridge with 5R4GYS rectifier made a very big difference with the Weiss DAC which is excellent and revealing, but lacked body and tone without the Analog Bridge.
Thanks,
Dan
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I know that this product was a long time coming and there were so many that contributed to this thread here. I want to thank all of those who helped me to make this the great product that it is!
(https://www.audiocircle.com/image.php?id=256848)
A great review of the Analog Bridge has just been published in LP International zine:
https://www.modwright.com/cms/resources/modwrightlprint323sd.pdf (https://www.modwright.com/cms/resources/modwrightlprint323sd.pdf)
Another review from Positive Feedback Online:
https://positive-feedback.com/audio-discourse/modwright-analog-bridge/ (https://positive-feedback.com/audio-discourse/modwright-analog-bridge/)
Winner of the 2023 Brutus Award!
(https://www.audiocircle.com/image.php?id=257006)