Poseidon's Voice Lazarus

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poseidonsvoice

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Poseidon's Voice Lazarus
« on: 9 Jul 2013, 12:12 am »
My personal incarnation of Dave Slagle & John Chapman's fully balanced Bent Audio TAP-X. The name (Lazarus), although having biblical references is used in a slightly different context,in order to appease the moderators and AC rules, i.e. Lazarus taxon or Lazarus phenomenon which apparently denotes organisms that reappear in the fossil record, after a period of apparent extinction. The TAP-X, over the years has undergone its own series of transformations (!), primarily the switch from transformer (Stevens & Billington) to autoformer (Intact Audio), as well as a newer enclosure which is presented here.

Ingredients for my (re)incarnation are as follows:

  • Rear panel engraved, and drilled through Front Panel Express; XLR connector mounting holes are threaded for a lock tight fit
  • RCA inputs are Connex brand; XLR connectors are Furutech
  • Top panel is dampened with Herbie's Grungebuster & 0.06 inches of steel for EMI/RFI shielding
  • Input and output signal wires are stock, i.e.  stranded Ohno cast continuous copper
  • Ground wire on the rear panel is gold plated solid core copper wire 26 gauge and stock enameled solid core copper wire
  • Cardas Quad Eutectic solder
  • All soldered connections are cleansed with CAIG ProGold


























If you want to see higher resolution photos, just go to my gallery here, select the photo, and pick 'HUGE.'

The build itself can be done by the novice, but with patience. Note that the input wiring most likely will look like a 'mesh' as it ensures the ability to easily service the unit, should the need arise. Use stranded wire here or else problems can surface when reassembling the enclosure, as smaller gauge solid core wire could snap easily. The output wiring and grounding looks much neater, as I have essayed to do myself.

Comments and questions, welcome. I will post my sonic impressions in a few weeks, probably under the 'Critics Circle' for wider appeal.

Best,
Anand.
« Last Edit: 10 Jul 2013, 01:32 am by poseidonsvoice »

jtwrace

Re: Poseidon's Voice Lazarus
« Reply #1 on: 9 Jul 2013, 12:18 am »
Look good!   :thumb:

Sonically I think you will hear that it just doesn't have a sound.  The measurements http://www.audiocircle.com/index.php?topic=115115.0 are absolutely superb as you have seen.

I love mine and I'm sure you will love yours too.   :D

Nick77

Re: Poseidon's Voice Lazarus
« Reply #2 on: 9 Jul 2013, 12:25 am »
Wow! Another beautiful Poseidon piece, bet it sounds magnificent.  :thumb:

Congrats, cant wait to hear your impressions.

richidoo

Re: Poseidon's Voice Lazarus
« Reply #3 on: 9 Jul 2013, 12:38 am »
Congratulations Anand, you do fine work! Hope you can bring it to our G2G!
Rich

WireNut

Re: Poseidon's Voice Lazarus
« Reply #4 on: 9 Jul 2013, 01:13 am »
I love it. Has exactly the ins/outs I'm considering. I've been talking with John Chapman the last 3 days. What a helpful guy he is. Really taught me a lot about balanced and unbalanced equipment and how the Tap-X works with each type. Can't wait to here your impressions.
The case looks great. Thanks for the HUGE pics, really helpful.
   

DaveC113

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Re: Poseidon's Voice Lazarus
« Reply #5 on: 9 Jul 2013, 02:05 am »
Wow, looks great!  :thumb:

Seems like a good alternative to an active pre since more gain is rarely needed. I would love to hear how an autoformer compares to a decent stepped attenuator sometime...




happyrabbit

Re: Poseidon's Voice Lazarus
« Reply #6 on: 9 Jul 2013, 02:21 am »
Nice Remote...Beats the plastic version.    :green:

Dwight

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mgalusha

Re: Poseidon's Voice Lazarus
« Reply #7 on: 9 Jul 2013, 03:12 am »
Beautiful work Anand, as usual I might add. :thumb: I had to have one after hearing or rather not hearing one, perhaps the only actually transparent piece of gear I've ever owned.

WireNut

Re: Poseidon's Voice Lazarus
« Reply #8 on: 9 Jul 2013, 03:57 am »

 Is this the new AVC-1 John's been working on/talking about with the exception of your mods :?:



   

JohnR

Re: Poseidon's Voice Lazarus
« Reply #9 on: 9 Jul 2013, 09:04 am »
Nice work  :thumb: :thumb:

poseidonsvoice

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Re: Poseidon's Voice Lazarus
« Reply #10 on: 9 Jul 2013, 10:28 am »
Is this the new AVC-1 John's been working on/talking about with the exception of your mods :?:

Yes.

Best,
Anand.

Chris Adams

Re: Poseidon's Voice Lazarus
« Reply #11 on: 9 Jul 2013, 12:20 pm »
Very, very nice build, Anand! I think I'm going to have to hear on of these. If I can have the transparency claimed and remote, I'm in.

jtwrace

Re: Poseidon's Voice Lazarus
« Reply #12 on: 9 Jul 2013, 12:21 pm »
If I can have the transparency claimed
I promise, you can.

Quote
and remote, I'm in.
johnc@bentaudio.com

rklein

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Re: Poseidon's Voice Lazarus
« Reply #13 on: 9 Jul 2013, 01:31 pm »
WOW!!  :thumb:

Another amazing build by my DIY hero.  Great stuff Anand!

I had the opportunity to hear the new TAP-X over at Mike Galusha's while I was out visiting my son in CO.  Mike got to play with my Exasound E20 DAC and I got to hear his wonderful system.  Mike also has the new enclosure and the TAP-X not only preforms great it looks great.

Congrats and enjoy your new build.

Regards,

Randy

John Chapman

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Re: Poseidon's Voice Lazarus
« Reply #14 on: 9 Jul 2013, 09:56 pm »
Hello!

Very nice build for sure! Time to enjoy it now that the work is done.

Thanks so much for taking time to post pics and the detailed description.

Thanks!

John

James Romeyn

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Re: Poseidon's Voice Lazarus
« Reply #15 on: 10 Jul 2013, 12:22 am »
Wow!  Great work!  Would love to hear it.

If one so desired, could one build unbalanced four channel with remote ganged master volume and remote trim (+/-10 dB range) for two of the four channels? 

If linear level steps what is magnitude in dB?  If level steps are non-linear, please quantify. 

What if any is schematic difference, transformer vs. autoformer? 

For anyone who has AB'd Bent vs. active preamp >$6k-8k USD I'd love to hear your impressions. 

jtwrace

Re: Poseidon's Voice Lazarus
« Reply #16 on: 10 Jul 2013, 12:41 am »
For anyone who has AB'd Bent vs. active preamp >$6k-8k USD I'd love to hear your impressions.
No comparison if you wan the ultimate in transparency & neutrality.  Bent TAP-X!!!

poseidonsvoice

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Re: Poseidon's Voice Lazarus
« Reply #17 on: 10 Jul 2013, 01:03 am »
Wow!  Great work!  Would love to hear it.

If one so desired, could one build unbalanced four channel with remote ganged master volume and remote trim (+/-10 dB range) for two of the four channels? 

I'll leave John to answer this one.

Quote
If linear level steps what is magnitude in dB?  If level steps are non-linear, please quantify. 

1dB steps. Note that this is a custom unit, and each of these Bent/Slagle autoformers cost $475 each. So for my fully differential/balanced build the autoformer cost alone was about $1900. Single ended would be $950/pair. It's a premium unit!

Quote
What if any is schematic difference, transformer vs. autoformer? 

This FAQ written by Dave Slagle should answer most of your queries: http://www.intactaudio.com/atten_FAQ.html

Quote
For anyone who has AB'd Bent vs. active preamp >$6k-8k USD I'd love to hear your impressions.

I know a few who had the 'DUDE' preamp and well...now they own the TAP-X, for what it's worth.

People need to first determine if they have excess gain in their system. Most do. If that is the case, and a TAP-X is in your budget, then run to John Chapman, before he comes to his senses :wink:.

Best,
Anand.

jtwrace

Re: Poseidon's Voice Lazarus
« Reply #18 on: 10 Jul 2013, 01:11 am »
I know a few who had the 'DUDE' preamp and well...now they own the TAP-X, for what it's worth.
Best,
Anand.
I also tried the Zesto Leto against it...

James Romeyn

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Re: Poseidon's Voice Lazarus
« Reply #19 on: 10 Jul 2013, 03:38 am »
I owned Bongiorno's $7500 Ambrosia line stage (2012 TAS award winner) and am very familiar with VTL's $17k tube preamp with SS output buffers. No tube line stage I know of compares favorably to Ambrosia.  Not close.  Noise (tube "whoosh"), coloration, etc.  Possibly the Dude and Leto are exceptions.  Modjeski's excellent Music Reference 100W tube amp employs all SS devices prior to the output tubes.   

I'd still love to hear the Bent autoformers.  On tube line stages, transformer output (VAC, at least one Asian brand) is preferable to tube output buffer.  Steve McCormack said his DNA500 SS amp performance improved with transformer input coupler vs. capacitor or transistor.  Lynn Olson's tube amps employ transformer coupling rather than tubes or capacitors.

The only "problem" with transformers is that high quality and high performance always costs real money.  I suspect OEM avoid it only because of cost and never for reasons associated with performance.

Can you imagine MSRP for this "Lazarus" transformer attenuator with dealer markup?  $15k?   

I suspect the component I'm using for line preamp employs a stepped ladder resistor switch (ala Shallco) shrunk and integrated into a line op-amp with requisite gain.  I often wondered if such op-amps with integrated level control exist only in mass market components or if such op amps are available to small OEM and/or DIY.

Compared to discreet circuits op-amps have magnitudes tighter tolerance for component values.