AudioCircle
Audio/Video Gear and Systems => Owner's Circles => Bent Audio Owners => Topic started by: John Chapman on 24 Mar 2006, 11:19 pm
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Hello!
Done.......
Info at www.bentaudio.com
Lots more to come after I catch up on initial orders. Kits, expansion modules, Tantilum Film resistor modules, 'Designer' control unit, etc..........
Also need to get time to clean up the website and take new pics, etc.... Lets just say it is a good thing I did not make a career of photography.
Through the next week I'll be e-mailing those patiently waiting on 'the list' to see if there is anyone who has not given up on me!
Please post any questions or suggestions here.
Thansk!
John
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very cool! Love the looks! 8)
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Very nice John
Sure looks like one we had here not that long ago.
Very nice looking and great details put into the craftmanship.
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Hello!
Done.......
Info at www.bentaudio.com
Lots more to come after I catch up on initial orders. Kits, expansion modules, Tantilum Film resistor modules, 'Designer' control unit, etc..........
Also need to get time to clean up the website and take new pics, etc.... Lets just say it is a good thing I did not make a career of photography.
Through the next week I'll be e-mailing those patiently waiting on 'the list' to see if there is anyone who has not given up on me!
Please post any questions or suggestions here.
Thansk!
John
Well, if it's passive it doesn't actually _do_ anything, right? Looks to me like a very expensive way of doing nothing...
But what do I know? :lol:
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Well, if it's passive it doesn't actually _do_ anything, right? Looks to me like a very expensive way of doing nothing...
But what do I know? :lol:
Apparently not much! :o
Very nice looking John.
Being a former owner of the previous version, I can attest to the sound and build quality. If I didn't go the room correction route, it never would have left my system.
Best of luck John.
George
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Hi John
If nothing else, I would have just bought it for the looks! As a NOH owner myself, I can unequivocably say that the new TAP will sound just as good as it looks! I cannot wait to get my hands on one!
May I wish you all the very best in this new endeavour! You have a sure winner in your hands!
Best Regards
Dennis
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Well, if it's passive it doesn't actually _do_ anything, right? Looks to me like a very expensive way of doing nothing...
But what do I know? :lol:
Apparently not much! :o
More than you. :lol:
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Well, if it's passive it doesn't actually _do_ anything, right? Looks to me like a very expensive way of doing nothing...
But what do I know? :lol:
Apparently not much! :o
Very nice looking John.
Being a former owner of the previous version, I can attest to the sound and build quality. If I didn't go the room correction route, it never would have left my system.
Best of luck John.
George
So you spent a lot of money on a component that doesn't do anything? :lol:
You're funny. :)
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More than you. :lol:
Depends on the subject, I'd imagine. :roll:
What about a TVC is not passive? Certainly the switching circuitry is not but that isn't in the signal path.
I can completely identify with the scientific mind but your posts here have been little more than antagonistic drivel. Why bother reading and posting on the forum if all you want to do is fight?
PS John C, if you want to trash this garbage, feel free.
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More than you. :lol:
Depends on the subject, I'd imagine. :roll:
What about a TVC is not passive? Certainly the switching circuitry is not but that isn't in the signal path.
I can completely identify with the scientific mind but your posts here have been little more than antagonistic drivel. Why bother reading and posting on the forum if all you want to do is fight?
Ah, just getting tired of the purple prose and arm-waving. Some people here make Harry Pearson be glad to be alive. :)
Unfortunately, there is less and less on AC that is worth reading. It's all devolving into voodoo and self-delusion.
I thought I heard that you had a mathematical background? I would think that this would equip you to see through the bunk. :)
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show me the purple prose in JC's post.
I am of a math b/g and said I like your scientific mind/approach. I don't agree with half of what is said on this forum and find I read it less and less these days, but there are quite a few great guys on this forum that I share a lot with. Something that I feel you'll never benefit because of your abrasive nature.
Being smart only gets you so far in life (usually exploited), it also takes a lot of people skills to be successul and truley happy in life, IMO.
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Hi John:
Congratulations! It's good to see that the new unit is ready for public scrutiny.
I am bemused by this negative guy. This sort of confrontational irrelevancy is out of place here.
Good luck,
Brian
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Hello!
I must admit I was a bit dismayed at the way this thread was skewing itself...... The last couple posts seem to be pointing to technical issues and I'd love to discuss those! I am a techie guy at heart and although measurements don't equal sonics I believe a product MUST measure and behave extremely well before sonics can be repeatable from system to system.
Bit of background - since it sounds like I thought like you a few years back. When a friend asked me about using TVC's as volume controls quite some time back I told him it was the stupidest idea I had heard - why use that when a handfull of resistors and a switch will do..... Then I thought about it from a techinical point of view - and I came around. The way a TVC translates impedance makes it 'look' like an active pre-amp - nice high input impedance and a nice low output impedance. Wound properly a TVC's bandwidth is very wide - combined with ultra low THD it seemed just what you want in a pre-amp. Lets not hold the fact it does this without power against it..... TVC's can (Again, if wound correctly do a very good job of converting Bal to SE and SE to BAL - again without additonal circuits in the signal path. So what we have is a way to adjust volume that behaves extremely well, can convert SE to BAL and BAL to SE, isolate ground loops, and provide 6db of gain if needed. If you need these functions then it's an option.
To back up my belief in techinical measurements I have over $50K of instrumention in my shop here inclusing an Audio Precision System 2 dual domain analyser, A 1ghZ 4 channel HP Infinum scope with a Preamble Instruments differential amp. My background is 30 years mechanical and electonic/computer design and programming (assembler, dsp, etc...). It's a no Voodoo zone......
I have to run now but I hope we can turn this thread around. If not I'll clean it up and return it to it's original intention - an anouncement of a new product and a place for users to post questions.
Many Thanks!
John
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show me the purple prose in JC's post.
I am of a math b/g and said I like your scientific mind/approach. I don't agree with half of what is said on this forum and find I read it less and less these days, but there are quite a few great guys on this forum that I share a lot with. Something that I feel you'll never benefit because of your abrasive nature.
Being smart only gets you so far in life (usually exploited), it also takes a lot of people skills to be successul and truley happy in life, IMO.
I was commenting on the general flavor of AC. My purple prose comment was not directed at JC. I just question the need for a passive or transformer-coupled "preamp" when we have active circuits that do a better job of marrying signal sources and power amplifiers.
You can't get something from nothing, and a transformer is ultimately working toward negative entropy. An active circuit attempts to increase order within a limited system.
I think I'll leave it at that, and maybe swear off AC for the weekend. :)
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John:
The unit looks awesome. A passive preamp with multiple input and output options, (including XLR), and a remote control. As far as I know, there's nothing else like this on the market. Most of the passive solutions out there do not include a remote, which blows my mind.
Also, a full-featured DIY remote control passive or active DACT solution is far from cheap. I think this TAP preamp represents a pretty good value.
I look forward to seeing more pics and learning more information.
Karl
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http://www.diyaudio.com/forums/showthread.php?s=14504da356836c880b8a1604e014146a&threadid=72588&perpage=10&pagenumber=12
On this thread you may see some more pictures from our day we held here and John put up his piece of art on the top of the stand.
Very nice work.
8)
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John,
Congratulations on a stunning looking piece, I'm sure its sonics are out of this world. :D
Best regards, Frank
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I think I'll leave it at that, and maybe swear off AC for the weekend. :)
How about for the rest of the year?
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Hello!
Thanks guys for all the comments! Again I never talk about my products sonics relative to other products or even other product types so I want to keep my posts technical. I find this discussion interesting since it was the technical aspects of the way transformers work that eventually attracted me to them - not a nostalga for the good old days. Transformers are used in TONS of pro audio gear for a simple reason - they behave well and get the job done. Any decent digital input on a dac has a small transformer at it's input - operating at frequencies way beyond anyones hearing! There are some things they do naturally and for those jobs they are the tool to use.
Since this comment describes EXACTLY what I though when first asked about the TVC idea I did want to reply to it:
>You can't get something from nothing, and a transformer is ultimately
>working toward negative entropy. An active circuit attempts to increase
>order within a limited system.
While a TVC does not give you something for nothing it does make decent use of what you already have. As the level of a TVC is turned down (and it is normally below unity gain for almost any system) it turns the excess voltage from your source into potential current - lowering output impedance. Very quickly it 'looks' exactly like an active stage from a black box point of view - nice high input impedance and very low output impedance. Instead of pissing away the excess voltage at the source component (like a resistor volatge divider does) you are making use of it. It lowers this output impedance by the square of the turns ratio so once you get beyond a few steps down from unity gain this effect really starts to kick in. It's just the physics of the way transformers work - same priciple that is used to kick down high voltage power transmission to the low volatge used in a home - you would not use a resistor based volatge divider for that!
There are cases where a TVC can not do what an active circuit can:
- If you need gobs of gain you need an active stage. The +6 db mode is very useful and works great in practice but the impedance 'translation' is working against you here so in my mind +6db is the most you can go for without putting too many demands on your source's ouput impedance. Most systems these days have excess gain and don't need +6db mode anyway. Just plug your source directly into your amp and see how loud the system is!
- If your source has a VERY high output impedance (approx over 1 or 2K or so) and you must run the level control at or above unity gain (ie. not getting the impedance kick as the level is lowered) then a TVC - or any passive attentuator - is not for you. You need a buffer and/or gain stage.
Fortunately these two conditions are rather rare so in most systems the TVC does a nice job of behaving electrically like an active stage - An easy load for the source and very low output impedance. Again, don't hold the fact it does it without a power supply against it! I am not saying it is inherently better than an good active stage - just that it is an option to an active stage for most systems.
Thansk!
John
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John
really great looking piece of kit. Have you any plans to put it out for review - I would suggest TNT as they have excellent credibilty (no adverts, no vested interests).
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Hello!
I have kept so may folks waiting so long that I'd feel guilty putting a unit out for review before I take care of getting them to customers. Once I get caught up I imagine it'll end up with a few reviewers. TNT does a great job of things so that'd be a fine spot if it works out.
Many Thanks!
John
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John
Nice looking unit.
Not sure if you had already covered these somewhere else (but I can't find it).
1) What does the display do? (Just the volume step?)
2) Is the display programmable? (eg does it show selected source / input?)
3) Is there a balance control (is this the purpose of having a dual display?)
4) Is there a phase invert switch
5) How do the expansion units connect with this? (The expansion units have inputs and outputs just like this unit)
Cheers
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Hello!
Thanks for the good questions. I'll reply best I can - please let me know if I cover everything o.k.
>1) What does the display do? (Just the volume step?)
The right and left displays show the right and left volume level.
>2) Is the display programmable? (eg does it show selected source / input?)
It is not programmable as such but for TVC based units it displays from 1 to 34 (for 34 2dB TVC steps) and when used with resistor based modules it diplays from 1 to 60 ( for the 60 1dB resistor module steps). For DIY/OEM this is changed via a jumper on the front panel board but for pre-built pre-amps the jumpers are factory set here.
On the right side of the unit are 6 leds to indicate which of the 6 inputs are selected. These are normally green but change color to orange for phase invert and to red when the selected input is programmed as an HT bypass input.
On the left side are 3 leds and 3 buttons - display on/off - tape output engage - and mute
>3) Is there a balance control (is this the purpose of having a dual display?)
Yes, the dual displays are for balance control.
>4) Is there a phase invert switch
Yes - On the front panel it is right between the next/prev source select buttons and also a button on the remote is used to flip phase. Phase is inverted via a complete extra set of input select relays for each input - so it does not add any extra switching to the signal path.
> 5) How do the expansion units connect with this? (The expansion units
>have inputs and outputs just like this unit)
The same enclosure is used for a a TVC expansion. For a resisitor based expansion units it is the same as the 'top' part of the enclosure - less the clear acrylic base plate. They connect to the main unit via toslink fibre optic cables - just like the original TAP system. Now you can connect up to 3 expansion units back to the main unit or daisy chain from one expansion to the next - adding as many as you'd like. These cables can be as long as you like (tested up to 100 feet) allowing expansion units to be placed anywhere in the room. Expansion units have a different front panel - with trim up/down buttons and green leds to indicate trim up / trim down. They will be avaliable with 1 input or 6 inputs just like the master units. I'll have pics in about 3 weeks when the volume order of front panels arrive.
Hope that helps clear up things.
Many Thansk!
John
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Now that you've pointed them out I can see some of the features in the pictures. (guess I should have looked more closely). A few comments/questions
On the looks:
I can now see that the acrylic base is actually attached as part of the design. I originally thought it was just a separate base (because the back panel covers the acrylic base). Any thoughts about integrating the base a bit more into the design? At the moment the sides of the unit are slanted to the right yet the base is straight up and down and I think clashes a bit where they join together (especially on the right hand side). Mind you I think the use of the acrylic base is interesting. Would the acrylic base light up/glow?
You should think about designing a logo (perhaps based on the frosted glass rods on the original TAP??) to go on the face plate
The 8 chromed studs used on the front look like they are buttons. How about some hexscrews that fits flush with the face plate and is the same colour? Less of a home-made look...
All these things are probably just a matter of personal taste but some food for thought maybe?.
Would be good to see the remote handset
On functionality
I think you mentioned that the +6db gain autmatically kicks in after unit gain. Does that mean there would a sudden jump in volume between 2 of the 34 steps?
Is the display brightness adjustable or just on-off?
Is it a soft mute?
Any option to use different types of RCAs (eg the new fancy WBT's)? For those that way inclined...
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Hello!
Compared to the NOH this unit does not look home made at all! I am playing with fasteners still - will likely go black on the front and leave just the buttons chrome. These are just final details.... The base does not glow. This unit is done for design - I think it turned out really nice. I wanted a low profile look but the transformers and the back panel connectors take some height so I came up with the integral base idea. I will have an alternate controller comming that is much more design oriented - more in-line with the original TAP controller but a new design.
Remote handset pics when the final one arrives. I have a few here but I am waiting for final button colors before posting pics.
+6 db auto mode worked out great. Was one of those 'wake up in night' ideas..... The level does not jump at all it just rises as you cross the unity gain point - ie. -4db, -2db, unity gain, +2db, +4db, +6db..
Display brightness is not adjustable - just on/ off. If in off mode it pops back on when a button is pressed or the level knob is adjusted then goes dark a short time. It is a nice brighness - easy to see in bright lighting but not too bright for a dark room. I did think about making it adjustable but did not want to complicate things too much on the board. Often brightness is adjusted by pulsing the display - something I would not do for noise reasons. Adding a dac to control brightness was a bit much. It's already the most full featured passive pre-amp ever made I think.....
Mute is just mute then not mute - back to where you were. It's smooth and quick.
I considdered using nextgens from wbt - they will fit the hole cutouts. The question is if they fit customers pocketbooks! A full complement of nextgens would add $$$ to the pre-amps parts cost - not something I shy away from in general but $350 of just RCA's is a lot..... May make sense to do a couple inputs and the main outputs for some folks - that'd be the most likely way I'd option it. Now I have time I am going to get a few and see how they install, etc then if they work out well I'll add an option for them.
Thansk!
John
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Fabulous looking unit. The important question is how does it sound compared to the old but goodie TX102S and more recent NOH?
Al
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Hello!
The schematic of the signal path of every version has been the same since day one. The new unit uses the same TVC winding geometry (ie. MK III) as the more recent NOH units. We added a few more taps (much to S&B's delight) for more volume steps.
I think the new one has a bit more of a sense of clarity - a surprise really. I was not expecting or shooting for a sonic change. I need to do a real blind A/B shootout to see if I can pick'em 100% of the time to test my impressions! I always do this when doing listenning tests and if I can't pick which is which almost 100% of the time I don't accept there is a difference.
The new unit's having the transformers not potted and the cleaner signal path are the only potential places for a sonic 'pickup'. All in all I am sure they will be close enough that I would not suggest anyone change to the new unit unless they really need the new features.
Thansk!
John
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The new unit's having the transformers not potted and the cleaner signal path are the only potential places for a sonic 'pickup'. All in all I am sure they will be close enough that I would not suggest anyone change to the new unit unless they really need the new features.
Hiya John,
Wonderful work!
Just wondering about more background as to why the tranny's are not potted. Also, do you have additional pictures of the transformer module? Specifically the mounting brackets to the chassis. What kind of vibration control is required to keep the transformers happy? I'm assuming even more diligence in keeping DC away from the TVC's is required now?
What is the total wattage for the Power Supply?
I'm a long-interconnect, short speaker cable sort of guy. I think, via expansion deck concept, I could have the control unit in a pleasing location for remote control, and then use the fiber link to control a 'one channel' expansion unit right next to the monoblocs? (Or maybe integrated monoblocs... hmmm, loose two RCA/XLR jacks in the chain). Am I correct in this idea?
Have you tested these unpotted trannies around higher than ambient temps? And, have you noticed any sonic effects?
The only downside I can think of your new setup is the tactile feel of the rotary switch... I doubt it can compare to the feeling of the Shallco. (And, yes, I admit it, I like my audio equipment to be a total sensory experience...)... any comments on the switch and how it works?
Not that I'm unhappy with my TVC's... just the better remote control would be great for my next project - Timeline... start I'm guessing 2007; want to know what my options are to design them in.
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Hello!
I'll reply best I can in-line.
>Wonderful work!
Thanks!
>Just wondering about more background as to why the tranny's are not
>potted. Also, do you have additional pictures of the transformer module?
>Specifically the mounting brackets to the chassis. What kind of vibration
>control is required to keep the transformers happy? I'm assuming even
>more diligence in keeping DC away from the TVC's is required now?
A few factors led to the unpotted design. - first it would result in a really large and complex can to pot the entire module and have connections for the ribbons and the few wires to inputs/outputs. This combined with feedback from some that unpotted transformers may have a tendency to sound slightly better (less 'stuff' packed around the windings and core) made me at least considder not potting. S&B makes lots of unpotted trannies that I have used (like the LO410) in lots of different situations and they have been very quiet. In my experience noise issues almost always come down to grounding - either system grounding or innner chassis grounding. The fact that many other TVC / Autoformer makers go naked added a level of comfort to at least test it. Once testing began I found the unpotted tx102 absolutely dead quiet - just like before. The mount is a pair of aluminum brackets that sandwich the core laminations and bolt to the bottom plate. I'll have more pics next web page update when I complete the diy parts section. This bracket does a nice job of closing gaps in the core and I used aluminum rather than stanless steel since it is a bit more inert from a vibration point of view. Also it must be a non magnetic material. It makes for a package very resitant to vibrations once all is together.
DC close by is not a problem but I'd leave a bit of space if dealing with extreme AC noise - but I'd suggest the same for the canned tx102 too......
>What is the total wattage for the Power Supply?
I use a 9V DC at 1 amp supply feeding into the chassis. The TVC modules and related front panel display take about 140 mA - not too much required. Any supply from 7V to 18V DC is fine - since none of this supply ever is part of the signal path it is not critcal but it must be DC.
>I'm a long-interconnect, short speaker cable sort of guy. I think, via
>expansion deck concept, I could have the control unit in a pleasing
>location for remote control, and then use the fiber link to control a 'one
>channel' expansion unit right next to the monoblocs? (Or maybe
>integrated monoblocs... hmmm, loose two RCA/XLR jacks in the chain).
>Am I correct in this idea?
This was exactly the design of the first TAP system years back using resistor based modules. It placed the modules right at the amp inputs to keep the output cable extremely short - as it must be in a resistor passive system in my mind. Although you could design a system just like you describe with TAP modules the TVC based TAP may be better located in a more traditional manner - near the sources. This is for 2 reasons:
1- The TVC's output impedance (abilty to drive the cables) is in almost all cases lower than your sources output impedance so the output of the TVC is better suited to driving the longer cables. The resistor based modules are exactly the oposite so it makes very good sense in that case to locate the modules at the amps.
2- More a practical and cost considderation - locating the level control at the amps requires long runs of cable from each source to the modules. If you have one source only then no problem but as the number of sources grow this becomes not practical anymore. Easy to do would be to locate source selection at the sources then run only 1 cable to each amps' TVC module - but since it's a bit more complex and given the impedance issues outlined above it would not offer any advantage anyway....
Good thinking there - for a traditional passive pre-amp that is exactly what would be done!
>Have you tested these unpotted trannies around higher than ambient
>temps? And, have you noticed any sonic effects?
The unpotted trannies will be MUCH better at withstanding higher temperatues - the potted tx102's at really high temps could I suppose melt the wax inside the can - although I have not run into this. I am talking tenmperatures way higher than a very very hot ambient temperature. Just like not mounting them right on top of a large AC transformer I'd suggest with prudent mounting this would be no concern at all. They are likely less affected than say a fluid filled electrolytic capacitor would be. I would not rule out sonic changes with extreme heat swings but I have no idea why it would be nor have I ever heard any myself.
>The only downside I can think of your new setup is the tactile feel of the >rotary switch... I doubt it can compare to the feeling of the Shallco. (And, >yes, I admit it, I like my audio equipment to be a total sensory
>experience...)... any comments on the switch and how it works?
This is one of the things I am most happy with. The optical encoder is very high quality and feels perfectly smooth when turned. I tried detented ones and there is no contest - the smooth level control feels much nicer. This encoder is (next to the TVC's themselves) the single most expensive part in the unit. The Seiden switches had a nice feel to them - for a mechanical switch they were very well done. I modify the Shallco switches here to improve the feel. Still not quite the Seiden but closer and WAY better than the stock Shallco switches. Nothing exotic to the mod - I change the spring and put a bit of silicone on the spring to damp vibrations - without that dampening they have a tendency to vibrate after each step in finished. Without the mod you'd need a lawn tractor motor to put a remote control on one. .....
>Not that I'm unhappy with my TVC's... just the better remote control
>would be great for my next project - Timeline... start I'm guessing 2007;
>want to know what my options are to design them in.
Glad you still like the TVC's! The new setup is much cleaner from a remote point of view. It will last forever and offers so many features that simply can't be done via remote with switches. Still I am not suggesting anyone with an older model upgrade - given the costs unless you really need a feature it makes no sense. Some are iindicating the additional steps down low in level or the ability to adjust balance or phase inversion via remote would be a big plus for them but those are a very special cases.
Thansk!
John
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Normally I try to stay on the technical side of discussions, but in this case I'll go subjective for once.
I attended the most recent RAWFest where John delighted everyone that attended by providing a prototype of the TAP as the pre used for the majority of the listening that was done. I brought along my active pre (my attempt to create a hybrid of a Pass Aleph P1.7 and a Pass X2.2) and my homebuilt version of Pass XA60 monoblocks, and was able to experiment with how the TAP compared / interacted with my equipment.
First, let me say that the TAP did not show any obvious deficiencies. There was absolutely no sign of rounded transients or softening of the tonal balance, the sound was clear and plently lively when required. The initial transient of a Japanese drum track was perfectly reproduced, and all of the decaying low frequency rumble was displayed in its full glory. IMO, there are definitely no audible bandwidth limitations with the TAP. It also portrayed piano correctly, something that I find many systems have difficulties getting right.
Second, I can also attest to the TAP doing a beautiful job of converting a single ended signal to balanced. The only source components at the event were single-ended. My monoblocks only accept balanced input, and have lowish 10K input impedance as well, and the TAP mated to my amps (in my potentially biased opinion) produced one of the, if not the, best sound of the event.
As to the question of passive verses active line stages, I also had the opportunity to perform a head to head comparison of the TAP against my (very) active pre. Were there audible differences? You betchya! But the differences could at most be described as subtle changes in shading. My amp perhaps had better upper frequency detail, but it could as easily be said that the TAP gave a more natural presentation.
However you slice and dice it, I can and do recommend the TAP. Cheers to John for a great effort!