AudioCircle
Industry Circles => ModWright Instruments (MWI) => Topic started by: modwright on 1 Mar 2018, 06:56 pm
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I have been exploring a few design ideas, while others are in the works and I WANT YOUR FEEDBACK PLEASE!
Class D Hybrid Integrated Amp, 200W, with most voltage amplification being done by Class A tube stage with built in phono and HP amp.
I have a prototype and it sounds very good! I know that people have different opinions about Class D. This is why I am on the fence. I would use Hypex modules and the power supplies would all be linear and over-built. No switch mode supplies!
This is different than what has been done by other companies. Our design uses modules with lower gain, so that most all of the voltage gain is achieved by the tube stage, where most of the sonic character comes from.
Hybrid Class D 200W Integrated Amp with nice stlying.
HP Amp and Phono built in.
Thumbs up or Down?
If thumbs up, what price range?
I have also been looking to build a lesser cost but equally high performance phono stage, in addition to our $7900 Reference PH 150 that has been well reviewed by Mike Fremer and Greg Weaver, earning Editor's Choice award for the last two years in TAS.
I am envisioning a two-box design. The power supply would be external and very smilar to our PS 9.0 mod supply.
The phono chassis would be matching size and similar styline.
MM and MC, ideally in the high 66-68dB MC range and also with adjustable resistive loading, on the fly.
Chassis would be steel with simple but elegant faceplates and controls.
Price range would be $2500 or so.
Thumbs up or Thumbs Down?
I am also currently working on a World Class, Class A Tube Integrated Amp!
I appreciate and welcome any and all feedback!
Thanks,
Dan Wright
President, ModWright Instruments
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Hi Dan,
I spoke with you after I bought my LS100 and ordered a metal remote. I was the guy that has a lot of Rogue gear as well.
For the first idea, I'd have to say "Thumbs Down." I think as consumers spend more money for more premium products in high end audio, they start drawing a line towards tube amplification or quality solid state. Hybrid Class D with tubes has been tried by other brands, notably Rogue Audio. I think that those are well-designed products, but the reception to them seems to have been underwhelming. You also see a lot of them for sale on the used market, often flipped a couple of times. They are not quite as smooth in all listening as one of their tube amps, or as a good solid state. Even if yours is smoother, more organic, I'm thinking buyers will still have a prejudice against class D. Sometimes what is in your head ends up affecting what you think you hear between your ears.
Phono Stage at a lower price point - I think that would be great, and I would give it a listen myself. I think that $2000 market is pretty hot now with the Manley Chinook, the Rogue Ares Magnum (which I have now) and the Tavish Adagio (stellar, by the way - a good benchmark). Your brand recognition as a more premium brand could put your phono in this price range on everyone's short list.
Class A All Tube World Class Integrated - Another thumbs up. Rogue sold a ton of Cronus Magnum integrateds, and they do not come up all that often considering how many were sold. I assume your competition and price point would be closer to the higher quality integrateds from Ayre and Aesthetix. I believe the new Aesthetic Mimas is around $7,000 and it's a hybrid tube and solid state design. The Ayre AX-5 is solid state and sounds pretty amazing, but I think that one is closer to $13K. Lots of room for a World Class Class A to slot in.
How about a moderately-priced tube-based power amplifier using KT150s or KT120s?
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I'll probably move to a tube phono stage within the next year and currently have the Chinook on my short list, so would be very interested in a competing product from you to mate with my SWL 9.0 Anniversary Edition. For me, flexibility is key; the phono stage shouldn't limit my future cartridge choices due to loading or gain limitations. Although I love the idea of on-the-fly loading adjustability, please give it a broad range. Herron uses loading plugs, which isn't an easy change, but it means you can accommodate any cartridge. The 66-68db gain seems really high if that is the only MC option. My current cartridge is 0.4mv and the phono stage (CIAudio PEQ1 MK II w/ AC15 MK II power supply) has 60db gain which translates to ~ 9:30-10 o'clock on the SWL9.0's volume knob at loud listening levels. With 68db gain, I would have very limited volume adjustability and it would rule out moving to a cartridge closer to 1.0mv in the future. A 68db option is great for very low output MC, but have some built-in adjustability.
Thanks,
John
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First of all, thank you for these replies. I hope that this thread will continue as the input that I REALLY care about, is from our customers and those who may be our customers. I am building gear for YOU, not the magazines. I am aware that the market is changing and I am trying to remain in sync with it.
To Drew769:
I want to build products that I am excited about AND that meet a market demand. Having said that, my heart lies in tubes and phono.
RE the first option of a Class D hybrid, while it is attractive from a price-point and manufacturing stand-point, I appreciate your input and I take it seriously. This is why I asked. Thank you!
RE the more affordable phono stage, I think there IS a market for this and i have ideas for a design that will take much of our PH 150 into a more affordable design.
To JohCH:
RE the phono stage, while the max gain will be in the high 60's, I am also considering a multiple gain setting, like the PH 150. I need to see if this is possible. If not, then I will shoot closer to 60dB for MC with the expectation that those with SUPER low MC's will use a custom step-up. MM gain will be about 43dB.
I agree that easily adjustable resistive loading is key and input noted about making this very adjustable, i.e. a wide range of loading options.
The two box design will keep noise levels down and keeping aesthetics clean and elegant but not 'flashy' will also keep costs down, focusing investment on performance! Thank you for pointing out the competition at these points. I am confident that we can produce a VERY nice phono stage at a price that can be afforded by a larger majority of our customers.
Thank you very much!
Please continue to post feedback, those who are reading this and would like to contribute your own thoughts and views.
Dan Wright
President, ModWright Instruments Inc.
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As for the hybrid integrated, as you stated, it's aiming for a price point. I feel there are probably many people already dabbling in class D amps with lower to mid priced tube preamps. I would imagine a good market from those who would like to own the Modwright brand at an attractive price point. The market share for class D has to be increasing from what I see. The new integrated could be a first step into the ModWright family tree. I imagine it worked well for Rogue.
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Count me in on the phone stage! I have heard the PH150 at length and if this is even a fraction of that unit, it will be KILLER. Can't wait...
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Hate to mention a potential competitor, but I have found W4S class D amps to sound amazingly good at their price points, and they seem to be doing well in the marketplace as well. It sounds like you are proposing what is roughly a one-box equivalent to a tube pre-amp into a class D power amp, a combination many audiophiles seem to have recently embraced.
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Was there not discussion at one point of a phono stage in the 1K range?
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Dan, the lower cost phono would probably be a good idea for folks with Modwright separates in the LS100/KWA100 price bracket, as that would slot a more complete Modwright solution between the SWL9.0 folks (integrated phono) and your DM/reference tube people (PH150 price range customers). Full disclosure, I have no vinyl nor interest in going there, so I'm not a potential customer, just an observer.
The top shelf tube integrated sounds like it fits in the stable of your other ultra-high end tube gear.
On the hybrid integrated, I think the prevalent opinion here so far is probably true, just casually looking around the market. If it had to come in at a higher price point than the KWI200, you would probably be looking at a hard sell, because people with that bankroll, I think, would more likely either be going separates in your current line, or going up to your top end tube gear.
As far as I know, the luxury goods market really still hasn't changed much (and at least in the USA will likely not be changing any time soon) - there is a market at the bottom end of the pool, and at the very top, but very few people shopping in the middle.
If you are looking to do something integrated in a lower price bracket, maybe an update to the KWI200 as is (all solid state), or maybe another new all solid state option that would come in lower than the KWI200? I'm sure the phono is still good to go in the integrated products, but I'm sure the DAC could likely be revisited considering the advances in the tech since first developed?
With somebody like Mivera here on AC (for example) trying to shake up an industry by putting the newest, top-of-the-line class D in a package out the door at or under $2K, it seems like a bit of a stretch to chase after that market with a more upscale product (hence why IcePower put the shut down of the same Mivera firesale selling their new modules at just over cost in DIY kits, as well as the same back-and-forth going in among manufacturers of end-user class D products arguing about cost-justifying "audiophile" pricing on semi-commodity built OEM electronic modules/goods).
Glad to hear from you, and best of luck! I hope my $.02 was worth the read. :)
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There seems to be a move in the middle of the audiophile marketplace for integrated systems. That's plausible given the rush to digital systems over the past decade and the desire for convenience, simplicity, and less clutter. The ardent audiophiles will continue to seek out separates. The increase (or not) in sales of your own integrated offerings will give you a good indication of the potential for your new products.
With regard to Class D, I think audiophiles have begun to realize that Class D has arrived at the point where it can sound as good as the best Class A or A/B systems out there, and it can be done a lot cheaper. I wouldn't have said this 3 months ago.
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Thanks guys. The phono is a go. The $1K phono is not out of the picture, but I have not had time to get back to it. there is a lot of competition at that price. I have several circuits worked out for it already though!
I am also looking at a new SS integrated in the future, at or near the price of the KWI 200.
The price I had in mind for a hybrid Class D integrated amp would be in the $4K range. There is competition here and people have different opinions about the technology. I can't build the Class D hybrid integrated that I have considered for $2K, but at $4K or so, it is a possibility.
Does this change anyone's opinion on the subject!
Thanks,
Dan
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I think some competition for the Pharaoh could work well, especially in your integrated had a little more of the tube forgivingness that by all accounts is lacking in the Rogue.
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Dan, I like the sound of all of your new product ideas. I'm very interested in your new Phono Stage concept. Typically, what time frame are we looking at for you to bring a new product to Market? I know many variables come into play, just a "good" guess would work!
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Hi and thank you for reassuring me that the phono stage design is a good idea!
I would say that time to market would be 12 weeks or so. The more input I can receive about options and functionality preferences from all of you the better! I will also be looking for Beta Testers when we are near production ready.
Thanks,
Dan
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Thanks for your reply Dan, I'll be looking forward to your release of your new Phono Stage! The 2-3K price range makes the Stage much more attainable for many of us.
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Thank you for that! I have a great design in the works!
Dan
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Dan, first let me state that I own the LS100 & KWA100se and they are in my main system. That said, I also have 2 tube integrateds in that system as well ( I switch every few weeks between the 3 amps) ; and I have a tube integrated in my second system The 3 tube integrated amps I have are an Ayon Spirit 2 KT 88 60 wpc push pull (it's in my 2nd system); Line Magnetic 518IA 845 22wpc SET; and Finale Audio 7189 MK2 7189a 20wpc push pull both in my main system. Therefore , my interest would be in the tube integrated and I would like to understand more about what you are contemplating e.g .tubes, SET or push pull, wpc etc.
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Hi Cheech, right now I am working on a 30W Pure Class A, Single Ended integrated amp using a KT150 or KT120 as the power tube. It is a unique circuit and should excel in driving speakers better than other tube amps because of its much higher damping factor. It is a diffiuclt design and I am still working on it. My goal is to debut it as a prototype at Axpona.
I have not designed a P-P amp yet, but that is on my list also. If this amp works out as I hope, it will be quite a break through!
A P-P integrated would be done to achieve more power of course. I should think 60W+, Pure Class A, zero feedback and with some unique design ideas that I also have.
Thanks,
Dan
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Thanks guys. The phono is a go. The $1K phono is not out of the picture, but I have not had time to get back to it. there is a lot of competition at that price. I have several circuits worked out for it already though!
I'd be all about this Dan, especially if its based on the 6922.
. BTW, still digging my Truth SA8005 !!!!!!!!!!!!!!!!! :thumb: :thumb: :thumb:
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Yes it will use 6922's!
Thanks,
Dan
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OK, things are moving along well with the $2500 phono stage project!
At this point, MC gain will be in the low-mid 60dB range. MM will be about 43dB.
Four tubes, external power supply and a two-chassis design, where each enclosure is 8"W x 5"H x 10"D. Because anode chokes are used inside the phono stage, the PS HAS to be external and the two boxes separated for quietest operation.
I am still working out how loading will be implemented. I plan at this point to have on-the-fly loading, in the same manner as the PH 150. It will be only resistive loading. I plan to have at least one MM and one MC input. At this price point, does it make sense to have more than one MM and one MC? Two MC's and one MM?
Aesthetics will be purposely simple and elegant, but not flashy. In order to keep the price to $2500, all money will be going into engineering and parts quality. It will look nice, but will not be all machined Aluminum. I expect a steel enclosure with a 1/4" AL face plate, laser engraved or silk screened.
To be clear though, the engineering for this design WILL trickle down significantly from our $7900 Reference PH 150 phono stage!
I anticipate having this at Axpona 2018 Chicago in prototype form!
Thanks,
Dan
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While I expect to have the Phono in prototype form at Axpona 2018 in Chicago, there is another product that I am also working on!
A Class A, SE Tube Integrated Amp is also moving along nicely, but will not be ready for Axpona.
I am shooting for 40W+ of PURE CLASS A, Single Ended tube power, in a high quality integrated amp! We are doing something very different here! Not push-pull, not SET. Pentodes and triodes will be used.
This will be a design Like No Other!
Dan
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I don't need to support multiple tonearms, so would rather not pay for that feature, particularly at this price point. Perhaps add that as an upgrade option for those who do, similar to how you offer the DAC and phono stage upgrades on some preamps?
My past two phono stages have employed separate power supplies, and I like the flexibility it adds. Given the anode chokes, how much separation is needed between the enclosures?
Thanks,
John
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12” seems like an ideal minimum. This is based on watching noise levels on the bench as I move the PS and phono enclosure closer and farther apart. I much prefer inductive loading to SS Constant Current Sources whenever possible!
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I have to agree with Johnch as I think that those who can afford the kind of table that has multiple tonearms would likely go for a more expensive phono stage, so I would vote for the mono function that you use on your PH150 as that is a more cost-effective and less labor-intensive way of enjoying mono records for those of us who either can't afford multiple tonearms and cartridges or if you can at least afford the cartridge then, who don't want to have to swap cartridges when playing mono records as unless you have a Jelco type tonearm it's obviously a hassle. I've actually been considering upgrading to a JC3+ from the built-in LS100 phono stage almost strictly for that feature as the PH150 is out of my price range at the moment and I can't even listen to my mono records anymore due to the fact that they just don't sound right on my stereo cart.
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OK, then that is settled. One MC and one MM input. One pair of RCA outs, no XLR outs.
I am very pleased with the prototype so far! I believe that the MM input will use a separate first gain stage from the MC, because the MC input is REALLY high gain. This is good for MC as it allows for A LOT of gain up front and the end result for MC is very quiet. The lower gain MM first stage will give just the gain needed.
If so, a single 12AU7 (likely tube to use) will serve as L/R MM input gain stage.
Mono/stereo toggle, check.
Mute toggle would be good I should think.
Rotary selector with six R loading combinations for MC.
MM input will be fixed 47K/100pf.
Rotary selector on the left will likely be: Off/Mute/MM/MC or something like this.
More soon. Thank you for the input.
I have looked at what is available at the $2500 retail price point and of course the Manley Chinook is a competitor. What will set ours apart will be the flexible on-the-fly loading and very low noise floor as a result of an external supply. Also, it will have very similar sonics as the PH 150.
Dan Wright
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Hi Dan,
I'd like to put in my 2 cents. I currently own a LS-100 with phono and Modded Transporter (later mod). Currently I use two different tube integrated amps, a MasterSound Due Trenta SE (30 W, KT-88 singled ended 0 feedback) and a Unison S6 (35 W, EL34 single ended). With these amps I'm using the LS-100 purely as a phono stage.
I had the KWA-100se in for a demo and frankly it didn't do it for me. Both tube amps have greater depth (particularly the MasterSound) and are more involving.
With that said I'd be very interested in a 2k-ish phono stage, so what you are planning sounds great.
Fantasy would be a single ended tube integrated with built in phono. There just are not that many out there although I'm not in a position to judge how desirable the phono is with a tube integrated.
There is one other thing Dan, because I know you are into vinyl (about 80% of my listening). The LS-100 is pretty awesome in that you can change the gain via the tube type (12AU7, 12AT7, or 12AX7). I'm using a Benz Ref Silver with 0.3 mV output and a 12AX7. So I recently tried a CineMag SUT with the LS-100 phono and the lower gain tube. There is no comparison, the SUT improves things that much. Its faster with loads of detail and not a hint of brightness, and of course a lower noise floor. Not sure if this is due to a limitation of the LS-100 board. Its one of those improvements where you are pulling out your old records just to hear how good they sound. That is when you know you've made a big improvement.
So the question is, is it a good idea to design a tube phono stage for MM gain and then use high quality transformers for the MC inputs? I know other companies do this. I wonder if you have listened to some step-up devices and what you think of this approach.
Thanks for the great involvement with your customers, regards,
John
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Thanks, I am working on the phono stage today actually. I have concluded that MC step-ups are a must. The downside is that they will also raise the price.
It will be between $2500 - $2900. Probably towards the higher cost with the use of Lundahl step-ups.
I am trying to accomplish this in one box also, with adjustable loading, MM, Mute, MC select on the front and stereo/mono toggle. All of these, including resistive loading for MC will be on the fly. No dip switches.
Thanks for your input! It is greatly appreciated as it is my goal to make the BEST phono stage possible in this price range! The goal is to approach the performance of the PH 150 at a much lower price-point.
Dan
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Hi Dan, when you write "I'm trying to accomplish this in one box" are you referring to where you house the SUTs, or do you mean you are no longer going for a separate power supply? Regarding the SUT approach, I have been reading a lot lately about people discovering much better performance using SUT with their MM stage vs. the MC stage, so definitely interested to see you pursue this path.
Thanks,
John
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By One Box, I am referring to an internal power supply.
At this point, I have a two stage circuit, capable of MM gain and then when MC step-ups are added, you have MC gain levels.
I can also design the first stage to provide MC gain without step-ups and there is a bit more noise. However, that input is too hot for MM inputs and then there is a separate MM input circuit required. It makes more sense to use MC step-ups for MC, and MM without, with circuit gain designed for appropriate MM levels.
It would be less costly to simply offer a MM only phono stage, but that is not what people want. When a step-up is offered separately, it is typically quite expensive and may use the very best step-ups available.
The Lundahl step-ups are used in our PH 150 and they sound exceptional.
So now the only decision is if the power supply will be external or not. Also, if it is external, whether it will be two 1/2 width enclosures or a full width phono enclosure and a 'brick' style PS enclosure, housing only the transformer and noisy elements on a long umbilical, to be tucked out of the way.
Thanks,
Dan
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All things being equal, I would say separate box for PS but you are building it to a price point. How much of the gain in SQ with separate box do you capitalize with your "limited" circuitry? Real estate can also play a role if you must separate them by a foot or more. In trying to anticipate a 3K mm/mc phono stage clientele, I am thinking one box probably makes more sense, imho.
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Well, I have made a change to one part of the circuit to allow for more tolerance of PS proximity. I will know based on that. The step-ups are fully mu metal shielded and as such, not a problem.
I won't sacrifice SQ even at the price however, so it will be what it has to be.
Two 1/2 width enclosures, if put on the same shelf, really offer no benefit to noise reduction. Despite the enclosures being fully steel enclosed, EMI will still be an issue, if the circuit is that sensitive to noise. Hence either two enclosures that are mounted on the same rack, but separated by at least 12", or a full width phono enclosure and the noisy parts of the supply in an external enclosure that can be tucked away anywhere and not on the rack.
Measurements BTW (so far):
Noise: -88dB MC (No weighting)
THD: < .08% at 1Khz
Frequency Response: 20Hz-50Khz (+/-.3dB)
Thanks.
Dan
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The unit will have MM and MC inputs with separate gain and loading:
MM = 47K fixed.
MC = variable resistive loading via front panel control, (On-The-Fly) no Capacitive loading.
Mono/Stereo toggle.
I had considered gain controls. What about a simple volume pot to allow precise gain levels for either MM or MC out selected?
MM gain of 44dB and MC gain of 64dB will handle nearly ANY cartridge you supply, unless it is an EXTREMELY low MC, in which case, you will use a specific step-up into the MM input.
But, if you have a .5mV, 1mV, 1.5mV MC cart or a MM cart with > 5mV output, you may want less than the max MM or MC gain provided.
If this feature is attractive, please let me know.
I am close to deciding if the design can be accomplished without sonic compromise in one enclosure or not.
Thank you,
Dan W.
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Is this infinitely adjustable gain within a specified range? If so, that's something I find very worthwhile as it affords a lot of flexibility for different cartridges, preamps, and amps down the road.
-John
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I can make the pot allow for gain adjustment within a range of say 12dB? 18dB? Infinitely adjustable!
This means that MM could range from 32dB-44dB or 26dB-44dB; MC could range from 52dB-64dB or 46dB-64dB.
I really do appreciate this feedback!
Dan
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IMO a pot is a bad idea. I think discrete setting where you know what it is works better.
But if you do use a pot make sure its hard to rotate and you need to use a screwdriver. The Audio Alchemy phono pre I am evaluating has pots for resistive loading and they move way too easy and its very annoying.
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OK, thanks for that.
Dan
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Hi Dan,
I'm very excited about this phono stage and appreciate your taking my feedback about the mono switch. You're going to use a 12AU7 tube in this, correct? I only ask as I just rolled the 5R4 tube in my cd player's PS 9.0 and my LS 100's 6SN7's with nice vintage tubes to great effect, so I'm anxious to roll my LS100's phono stage, but will obviously hold off if you're not using the same tube in this new project.
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At this point the design only uses two 6C45's and two 6922's. It will likely be SS rectified, like the PH 150.
The 12AU7 was going to be used for MM input only, if I didn't use Lundahl step-ups. At this point, I think I will use the step-ups, and as such, no 12AU7.
Thanks,
Dan
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As you noted the Chinnook is a potential competitor, but the Taversh Design Adagio is much more similar to what you have described with its separate PSU, two half width enclosures, transformer step ups for MC, on the fly adjustments, and a price that makes it appealing (especially considering the performance). That is the benchmark to beat in my opinion.
Several months ago you mentioned a discreet SS quiet phono stage in the $1k price range and that sounded interesting. Is there any plans on developing that product?
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Hi Greg, the Tavish design is interesting and of course at an attractive price.
I am confident that our design will be QUITE competitive, given the pedigree of the PH 150 from which it is derived. I have not decided if it will be one or two boxes yet. It really depends on a couple of factors.
As for the $1K SS design, that is still on the drawing boards also and will follow in time.
Thanks,
Dan
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IMO a pot is a bad idea. I think discrete setting where you know what it is works better.
But if you do use a pot make sure its hard to rotate and you need to use a screwdriver. The Audio Alchemy phono pre I am evaluating has pots for resistive loading and they move way too easy and its very annoying.
Is a detented volume pot a possibility and would that address this concern?
-John
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While I hear you regarding the loading resistance, that it should be clear what the setting is, the variable gain is such that, being infinitely variable, you set it for your ideal listening and leave it alone. If we do this, it will be a simple potentiometer, probably with a distinct and limited range, but not with detents.
The only other way to go would be a distinct set of discrete resistor settings with specific attenuation. I just thought that the infinitely variable attenuation would allow for the most flexibility because everyone's system is different. You have preamp gain, amp and speaker sensitivity to consider.
Thanks,
Dan
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Hi Greg, the Tavish design is interesting and of course at an attractive price.
I am confident that our design will be QUITE competitive, given the pedigree of the PH 150 from which it is derived. I have not decided if it will be one or two boxes yet. It really depends on a couple of factors.
As for the $1K SS design, that is still on the drawing boards also and will follow in time.
Thanks,
Dan
Hi Dan,
I am a fan of your products and I have owned a few in the past as you know. I only mentioned Tavish Designs Adagio because you mentioned the Chinook as a competitor and thought a two box tube phono stage would differentiate your product, so I brought up the Adagio as a point of reference since it would also be a competitor for a two box tube phono stage. I have no doubts your product would be a solid performer.
The PH-150 is outside the price point I want to spend, so your phono stage is of interest, especially with trickle down technology. I also like the idea of the two half width cases, because I could put the PSU on a different shelf and have my own MC step up sit next to the phono stage if I want to use the MM input.
Greg
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Thanks and good point in support of the two box approach.
My conflict in this regard before, was simply that if the two boxes are 1/2 width, if placed side by side on the rack/shelf negates the benefit of the power supply being outboard. I appreciate any/all feedback in this regards as this is a key decision in the design process.
I appreciate all of your feedback very much!
Dan
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Well, it is looking better and better!
I just did more tests with both MM (47K load) and MC (200 ohm load) with step-up at 1:10.
MM Gain = 48dB
MC Gain = 68dB
Actually a bit high and will be adjusted down possibly. Unless I do include an infinitely variable attenuator pot. If so, then this may be ideal!
Noise Measurements just completed on the Audio Precision:
MM = -95dB (unweighted)
MC = -77dB (unweighted)
That is pretty darn good for a tube phono stage!
Thanks,
Dan
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Impressive measurements Dan!
Will the phono stage be an inverted design like the SWP-9.0 SE or will it be phase correct?
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It will actually be phase correct.
At this point, I am leaning towards a one box solution, with the looks and styling of the SWL 9.0 Anniversary Edition preamp:
(http://www.audiocircle.com/image.php?id=145059)
This means internal power supply, MM and MC input, variable on-the-fly loading (6 values) for MC.
Stereo/Mono and Mute.
Possibly a multi-position attenuator selector to choose from max gain to: -3dB, -6dB, -9dB, -12dB, -15dB, -18dB. This would allow the greatest degree of system flexibility based on cartridge and system gain. I may also increase the total MM/MC gain to as much as 50dB/70dB if so.
I know that some people would also like balanced outputs, but that would be a cost add. I am tryin to stay under $3K, but an option with balanced outputs via transformer coupling is possible. It just depends on the level of interest.
The goal is to build a line of '9.0' products, to complement the existing exceptional $2900 SWL 9.0 Anniversary Edition preamp. It is based on our very first preamp, the SWL 9.0SE. The SWP 9.0SE was the matching phono stage and it is still in demand today. The PH 9.0 would be far superior to the original SWP 9.0SE.
Lastly, if it works out, I would like to consider adding to the lineup, a 50W Class A SS amp, to fill out the '9.0' lineup.
Again, all thoughts and input welcome.
Thanks,
Dan
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The PH 9.0 sounds like a Winner, I for one would like to see a Balanced Output "Option" as I currently have a 5 meter run between my Phono Pre and my LS-100.
And, that the PH 9.0 is offered in Black!
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I am going to look for the most economical way to accomplish this. It will require a pair of output transformers to convert SE to balanced. I will see where I can source the best transformers for this purpose without adding TOO much cost. The chassis will be designed to include a pair of XLR outs. I will likely install them only on the balanced models, and have a cover plate over the XLR outs for those without.
This way, if a customer wants the balanced out option, then they can pay for it. If not, then they don't have to pay extra for an option they won't use.
Thanks,
Dan
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I had class d yes ago. Harped on lots.
You probably won't agree with is the BASS. I just can't get over it. Yes strong. Yes well defined. But for me ,it was just way way way too much of a good thing. I was never able to get over it. I just don't go for that presentation I guess. Other then that it's hard to explain.
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Thanks for your feedback. I have decided to shelve the Class D hybrid design for now. I will work on a Class A-B or Class A hybrid design instead.
After Axpona will start digging into this. Perhaps by RMAF in the fall, we will have a hybrid integrated (A or A-B).
Thanks,
Dan
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I am going to look for the most economical way to accomplish this. It will require a pair of output transformers to convert SE to balanced. I will see where I can source the best transformers for this purpose without adding TOO much cost. The chassis will be designed to include a pair of XLR outs. I will likely install them only on the balanced models, and have a cover plate over the XLR outs for those without.
This way, if a customer wants the balanced out option, then they can pay for it. If not, then they don't have to pay extra for an option they won't use.
Thanks,
Dan
Dan,
Thats a great idea as I think there are still a lot more people using unbalanced connections on their phono pre and I know that for me, I would like the option of ordering the less expensive RCA only version.
Aaron
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OK, thanks!
Dan
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Not interested in balanced.
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It will be an add cost option.
Dan
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Hello Dan,
I'm curious about your work on a new integrated tube amplifier. Are you still working with KT tubes? And are you planning on including either a MM or MC phono-input on the integrated amplifier?
I've owned both an SWL 9.0 and an 36.5, and have heard a few of your amplifiers before as well. Lately I've been very curious to hear your Ambrose A30 amplifiers (I like the sound of EL 34 tubes very much), and have always appreciated your designs. Those mono amps are gorgeous, but I haven't pursued them too aggressively because they are out of my price range. But your comments on a tube integrated amplifier have my intrigued. Please keep the updates coming. Your engagement with customers and listeners is very refreshing.
Good luck at Axpona.
David McCallum
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Hi David, I am still working on the tube integrated and yes, so far the basis of design uses KT150 or KT120. The goal was 30W-40W with a single power tube.
I am waiting on some customer transformers from Electraprint to finalize this.
As for phono stage, that would be ideal. It will depend on noise and if I can pull it off.
Thanks,
Dan
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Photo of Proto/Concept PH 9.0 Tube Phono Stage, MM/MC 48dB/68dB. Price TBD (<$3K)
(http://www.audiocircle.com/image.php?id=178701)
At Axpona, the PH 9.0 can be seen and heard in room 604 with Studio Electric, ModWright and Zu Audio.
This is merely a concept/proto. It was built as a two box design, but I am considering making it a one-box design with aesthetics similar to our SWL 9.0 Anniversary Edition preamp.
(http://www.audiocircle.com/image.php?id=145059)
Feedback and input about this is certainly welcome.
Thanks,
Dan W.
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I absolutely love the styling of the prototype phono stage and find it especially pleasing in black color.
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Thanks, I appreciate that!
The finish is clean and elegant. The graphics are laser-engraved, not silkscreened.
The question is, one box or two?
Take care,
Dan
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I prefer two boxes, especially if I want to place my MC step up next to the phono stage and place the power supply on a lower shelf in my rack. If I use the internal step up transformers then the one box would probably be more convenient.
With two boxes and the power supply far enough away I suspect the two boxes would have a quieter noise floor.
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Based on your final topology, can the two boxes be placed close together as in the photo, or do they require significant space between them? Is there a price difference between the two options? All things being equal, I prefer two boxes as it provides maximum flexibility when tracking down a hum problem.
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If used side by side as per this design, it is noisy. It is ideal that the two boxes be about 12" apart or at least on separate rack shelves. It really has to do with proximity and orientation of the power transformer to the inputs and step-ups.
Cost-wise, there is really not that much difference. The cost of two boxes and umbilical, umbilical connectors, two face plates, etc., has cost too. The one box design would have a bit more sophisticated aesthetics probably, because i would want it to match the SWL 9.0 Ann Ed in the same family, and this costs money too.
The other way to go, to keep it a two box design and also keep the form factor of the phono stage 1/2 width as it is: Make the external supply a 'brick' type small enclosure, that contained the power transformer and power choke only. It could then be tucked away anywhere, away from the phono box. It would not be a 'display' piece, and would not have an AL face plate. It would likely be a black steel, powder-coated box with no switches. Just a power IEC input and umbilical out.
The phono stage could then be very similar in size to what is shown in the photo. In fact, if that were done, the total enclosure cost would be a bit less and this could either drive the cost down a bit, or allow for better quality parts in the phono stage itself.
I see two things here from the feedback. Outboard supplies are desirable because they keep things quiet! They are inconvenient if they take up another shelf space. However, if the umbilical were say 6ft. long and the supply could be on the floor and off the rack, then it may be more attractive.
If that were the case, would it also be attractive for the phono enclosure to be 1/2 size, in case you want to put it beside your TT on a wide shelf, use the MM input with exotic high end Step Up transformers, etc.
All things being equal, is it more appealing for the phono stage to be full width, or more compact?
Thanks,
Dan
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I do not care about the aesthetics of the power supply enclosure compared to the quality of the components, so cost saving or using the money saved on the enclosure towards better quality components is where I would place priority. I would like 6 ft umbilical so can place the power supply low on my rack. Also if there is a possibility of an upgraded umbilical that can improve the sound that would be a nice option.
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If we go this route with external supply, the umbilical will be an off-the-shelf 4-pin or 5-pin XLR type. We will of course also offer upgraded umbilicals, but I wanted to be clear what the stock cable would be.
Thanks,
Dan
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"The phono stage could then be very similar in size to what is shown in the photo. In fact, if that were done, the total enclosure cost would be a bit less and this could either drive the cost down a bit, or allow for better quality parts in the phono stage itself."
I like the idea of using the cost saving for better quality parts in the phono stage itself.
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I'd prefer the PS to be a non descript, black brick that I can place on the floor behind/next to the rack, and either lower the price, or use better components in the phono stage. Take a look at the power supply for the Lehman Black Cube SE II for inspiration. BTW although this seems to be the consensus among the people replying to this thread, I have no idea how the typical buyer in this price range feels about 1 box vs. 2, and hidden PS vs. housed in a display quality enclosure. Are any competitors in this price range using 2 boxes and if so, how are they treating the PS?
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I have decided that it will be a two box and I believe that the 'black box' approach to an external supply makes the most sense in order to keep costs/price down. The savings will be applied to better parts in the phono or a lower retail price.
To be clear, when I say 'black box' supply, I am not talking about a wall wart. Rather, a steel box that includes the transformer, choke and basic DC rectification circuitry. The enclosure will be powder coated steel and not finished as a display piece.
The umbilical will be a stock off-the-shelf 4-5 pin XLR cable.
We may offer upgrade paths as follows:
Upgraded external supply with tube rectification or more sophisticated design.
Upgraded custom umbilical.
XLR transformer coupled output for fully balanced operation.
The goal will be to make the base unit the very best that it can be and represent the highest value and performance possible. For those that want to pay more for the upgrades, they will be available at time of purchase or as future upgrade path.
Thank you very much for the feedback!
Dan
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Dan, I think the 2 box solution is best. It solves your noise issue and gives people flexibility if they have size issues for the phono pre placement.
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Dan,
I really like your approach. Best parts for the phono preamp and a simple power supply box. Upgrade options also make sense to me. Hope you have a productive time Axpona.
NB
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Thank you! It is the approach I have always taken with our products.
Dan