Response Audio / Audio Note custom DAC

Category: Digital

Let there be sound…

Everyone has there own taste in what constitutes the “ultimate” DAC – We all recognize the preferred and in-vogue names; Esoteric, DCS, Meitner, Zanden, Accustic Arts, and so on… My personal flavor brought me to the Audio Note (AN) convent.

Those who worship here know all to well the intoxicating nectar the Gods favor as you climb the AN ladder. Unable to quench my lust for the cost-wise-unobtainable DAC 5, I decided to turn to the AN kits. During my internet reading and research into kit building, I stumbled across a small shop in up-state New York who does some amazing AN kit builds; Response Audio.

Owner Bill Baker has a long history of customization, modifying, and more recently manufacturing his own line of high-in audio gear. So after several conversation with Bill, I decided to have him do a radical custom DAC kit build for me – a custom DAC 3.1 TC Reference MBX.

This starts off as a AN DAC 3.1 kit with balanced outs via transformer coupled 5687 valve output stage and the Signature digital board (populated with N Black Gate caps and AN Tantalum resistors). Bill then takes the kit’s M2 power supply and doubles it – for a completely dual-mono power supply and adds to that generous amounts of Dale resistors, massive Mundorf film caps, and silver wiring.

But we didn’t stop there… A cup of Elna Cerafine caps, a pound or two of VH Audio V-Caps, sprinkle in some Caddock resistors, plop in a AN silver digital input transformer, a premium N-K DAC chip, two AN super mumetal 496 IV transformers, and for good measure, two AN Ultra HiB output transformers – stir it all up and… BOOM!!! It’s alive…

I know, I know, enough with the smoke-n-mirrors, what does the beast sound like – well, I have now found the state of verisimilitude.
Read on for my listening notes…

Charles Mingus / Blues and Roots
Open, vast sound stage, overall deep tone, clear, drum kit very real with weight rhythm clear, no congestion with horn loaded passages, finger snap of the bass string / string hitting fret, light airy cymbals, mellow deep vibrato yet tight not overblown baritone sax – reedy/nasal intimate alto & tenor sax, earthy & woody bass, very deep complex concurrent horn passages with no grain or tonal breakdown

Dusty Springfield / Dusty In Memphis
Clear, crisp, sparkly, rich sweet transcendent soulful sensual presence

Van Halen / I
Clear, crisp, major increase in dimensionality & sound stage, significant air around instruments, cymbals especially shimmer and sound brassy – major improvements over previous listening session with this album – I’m really hearing dynamics I’ve never heard before. David’s voice sounds nicely smoky and Eddie’s guitar sound like a chain saw, ripping cleanly and powerfully through cords – articulate though, not edgy at all.

Diana Krall / Love Scenes
Sweet brown-sugar whiskey voice, airy. Deep powerful bass, full clear organic percussive piano. Intimate, personal soundstage – in room – I can close my eyes and see her lying across a piano.

Art Blakely / Moanin’
Start dancing as the sound stage unfolds out across and deep into the room. Sassy mellow horns. Drums and piano are stout, bass solid.

Chicago / Chicago Transit Authority
Spacious large sound, no congestion or grain on intense horn passages, clear but not edgy, dynamic, punchy, clean.

Stan Getz / Getz/Gilberto
Airy, festive, amazingly live sounding, ohhh so smooth, sweet, open air space, intimate soundstage, full weighty bass.

Dave Brubeck / Time Out
Airy, fast, such an amazingly realistic brassy ring to cymbals/triangles, rich, live, powerful, clear mellow percussive airy full piano.

The Grateful Dead / American Beauty
WOW – gooey eye candy at its best. Crisp brassy cymbals, stout fast drums, weighty bass, mellow strings, harmonious vocals, super large soundstage broke out the walls of my listening room – transported me to the Fillmore. Powerful live sounding. Exxtra Punch & slam – hand to turn down the preamp because the L Quad went into “safe” twice. I could hear what sounded like a pin drop and I could hear Jerry’s guitar tube amp hum on the live version of Attic of my Life.

More booty-shakin drive which propels tunes outward in soundstage width and adds gravity to soundstage depth. Texture, contrast, amplitude. Lives & breaths air and life into recordings like I have never encountered before. Fast edged and sharp striking articulate in micro detail yet sweet mellow and sexy smooth, best described as “Organic definition”. Shinny sparkling treble and boisterous dynamics and low-end fortitude. The cleanliness and the control of the sound is impressive. Vivid. Rich timbre. Absolutely gorgeous. The attack and decay of the notes are totally natural and believable. Room ambiance and background sounds on the discs come through like never have I ever heard before from a CD. Adds incisiveness and full bandwidth dynamic slam and delicacy. Easily explores complex musical passages without compression or decay in micro detail. Amazingly three dimensional depth and breadth to the sound stage. Ambience. Organic blending of overall sonic experience yet minutely crystal in articulate detail and clarity. Dimensionality, space, and air sounding instruments. Absolutely amazing realism and character to instrument tone and expression.

What else can I say – WOW…

Needless to say, I am ecstatic over this DAC and Bill’s work. If I had one gripe, it would be turn around time – it took almost a year to birth this creation. A frustratingly long time for the impatient, but now that it’s all said and done, I have to say well worth the wait!!! Bravo maestro and applause for Bill. This is without a doubt the best digital front end I have ever heard and ‘dare I say it’ rivals most analogue I have auditioned. Truly absolutely fabulous.

Listening conducted after 450 hours of burn-in on DAC and transport in unison.

System consists of; PS Audio PWT, Response Audio custom AN DAC, Atma-Sphere MP-3, Atma-Sphere MA-1, Quad 988, Grover Huffman Sc digital cable, Grover Huffman Sx intraconnects & speaker cable, Grover Huffman / Virtual Dynamics / Shunyata power cables
I should note - as far as the delay that I mentioned above, Response Audio did have multiple significant delays resulting from Audio Note UK in providing upgraded transformers and such. I had forgotten to articulate that in my review comments.

But, I'd like to reiterate; delays/wait times or not, this DAC is such a monumental achievement in realistic music reproduction that the build time was well worth waiting for, whatever the reason...
You still have that AN DAC 3.1 kit (upgraded)? I too have a 4.1 kit that I have maxed out. Basically did the same as you but also got hold of a DAC 5 UK digital board (lot better) and then upgraded the caps in the PS for AN Kassai's. Also replaced the AN Copper caps with Duelund Cast. There is more in that DAC to be had. IMO I think it can sound better (more transparent and faster) than the AN DAC 4. The AN DAC 5 sounds slow and coloured to my ears, not at the level it should be by modern standards for anything like the money asked for it.
Hello, I haven't looked at this in a while, obviously.  

Yes, I still have this AN DAC and love it more than ever.  At times I have thought about hearing what the latest/greatest may deliver (like Lampizator) but really I am so satisfied I do not see a reason too...  I may start looking at some new caps in the near future for it and I have always wanted to go to the all silver to silver nickel AN output transformers but need to get my last youngest kids through school before I can spend the ga$illions on those transformers...  
Hi grateful.
I am glad to hear you are still enjoying the custom DAC. From what I remember in building it, not much more to do. However, if you are interested in having a DHT output from the DAC, or any other sourve, we now have a 300B output stage (buffer) that does wonders with DACs and CD players. 
You can see more on my site at ResponseAudioNY. I would work with you on it as well. Always glad to see people still happy with gear after so many years. 


Hello! I came across this thread today and was wondering if you have continued to work on projects like the ANK Dac mod described above. Are you familiar with ANK’s latest 5.1 Signature Dac?