Seeking Advice on NOS DAC


Looking to purchase an NOS DAC, budget is $1500.
Currently available for sale are:

- Metrum Acoustics Hex digital converter  (used)
- Metrum Acoustics Amethyst DAC       (new)
- Acoustic Plan Digimaster Tube DAC     (used)
This is a German-built NOS, 24-bit R-2R resistor ladder network, PCM1704U-K converter with 4 tube EC 86 triode outputs.
- HOLO Audio Spring DAC – LEVEL 2    (new, but over my budget of $1500)

My primary listening is via the PS Audio PWT, while music files on my Mac are steadily increasing. I’m thinking NOS due to my large collection of Redbook CD's.

So, any experience or comments on which way to proceed is appreciated.

128x128lowrider57
I'm using PWT with Exogal Comet Plus, and very happy with results...they are available used, and sometimes new at your price
A bit above your budget, and only redbook basically, but very good is the Concert Fidelity DAC-040

https://www.audiogon.com/listings/da-converters-2017-11-17-digital

This is the non battery version, which is what I have myself.  There is also a battery version available here but that is a bit more still:

https://www.audiogon.com/listings/da-converters-battery-powered-tube-dac-2017-11-14-digital

And here is a very helpful review thread:
https://forum.audiogon.com/discussions/review-concert-fidelity-dac-040-da-converter?highlight=concer...

  
@jl35 , always great reviews for the Exogal. I know it uses a FPGA, does it have a laid-back presentation? Not looking for anything "in your face." As I stated, need a dac that faithfully presents Redbook.







If you like the non over sampled sound, multibit Schitt or La Scala are excellent choices with the Schitt “Gumby” being quite a bargain and the “Yiggy” of reference quality. I’d advise frequenting Computer Audiophile for opinions on DAC’s as Agon isn’t that up to date on digital trends. The Johnny Darko DAC index is also useful.
Thanks, everybody. I should have mentioned that I auditioned the Schiit “Gumby” and it sounded a bit too aggressive in my system. Excellent dynamics and soundstaging, but my system is very revealing and it wasn't what I was looking for.
  I've owned a Chord with FPGA and found it very smooth, so the Exogal Comet Plus is on my list. The FPGA that reshapes the waveform is a major advance in DAC technology.

Because of the low Input Sensitivity on my tube amp (1V), I'm limited to a DAC with good volume control or one with low output voltage such as the Metrum Acoustics Hex.

And thanks, David. I'll check out the Darko DAC index. I like his reviews.

I don't have a lot of experience with DAC's but recently purchased an audio alchemy DDP-1 with the optional power supply. It's exceptional with redbooks, which is about all I own. The preamp section itself is also very good (it replaced a Melos 222 & betters it in every way) & has analog inputs. Audio Advisor is selling these currently for $1500. If you have time, check out the review from absolute sound.  
Low- I haven't heard the Border Patrol, but it checks the right boxes, tube in the power supply and the more robust version with one output of your choice is below your budget. I was also looking at some of the Audio Note Kits, but the Border Patrol may do the trick. No way to listen to it, though, unless you find an owner. 
Thanks guys, both DAC's look interesting. And @whart  , the Border Patrol does "check the right boxes."

@jond ... Enjoy the Music gave the DAC2.1 Signature a  phenomenal review. It looks like everything I could ask for in a DAC.
My only issue is the review is from 2005. So I'll ask you, what type of questions should I ask the seller/dealer?
Condition of caps and the tube circuits come to mind. Also, there is no USB input.

Oh, wait a minute. I just saw a pic of the DAC2.1 and it only has balanced-outputs. My system is SE tubes and I don't know if I want to use XLR adapters.

Don’t know if you’ve heard of or thought of MHDT Labs, but I have their Balanced Pagoda, and it sounds amazing. Particularly with good tubes.

I too and a big fan of the NOS sound, after having had a Scott Nixon DAC for a long while.

I highly recommend the Pagoda. 
@lowrider57 AN dacs of that vintage don’t have USB inputs, mine doesn’t I use coax. You could of course get a usb/spdif converter. As far as questions I wouldn’t stress too much about caps my DAC is Circa 1995 and still going strong. It’s a pretty low stress environment in terms of the output stage. perhaps ask for some interior pics? I don’t think there’s much to worry about AN has fantastic interior build quality.
Stretch your budget just a little for a used Pavane. You can later upgrade if you feel the need.  The base model is much better than the Hex and their Level 3 (run through a very good preamp) beat their highly rated Adagio head-to-head, for my tastes, in my system - although the Adagio was very good and other listeners may have called it differently.
I bought a Dodson D 217 mk. II d with 218 software upgrade and used it happily for over a decade. However, one of my system goals has always been to achieve ultimate transparency without crossing over the line into harshness. So when the Hex came out I decide to give NOS a shot and pulled the trigger and I do have to admit, the filterless approach does come off as a bit more organic and the micro shadings/information are more cleanly and decipherably presented. Then the Pavane reared its ugly head and after much deliberation and gnashing of teeth, I decided to take the plunge. It is MARGINALLY better but the sweet spot for the money is most certainly the Hex in my book. And I paid $3800 for my Hex brand new so at $1500, I'd be all over the one you're currently eyeing up.

I listen to redbook CD 100%.

Best of luck to you, whatever your decision.


Many thanks to @mitch2 and @acresverde . The Pavane will probably be out of reach (even used).
In addition to multiple positive reviews, Darko really liked the Hex. And there are two currently for sale; I may stretch my budget to $1650 for the right DAC.

Thanks, @jond . I messaged the dealer with some questions. I asked if any service was performed and if the original electronics were intact (very high-quality components are used).
I'm wondering why this unit is so reasonably priced, so I asked for pics.

Can anybody recommend a USB/spdif converter? And wouldn't this signal need to be reclocked and the 5V power be isolated?
FWIW, when I sent my Pavane over to the Netherlands for the upgrade, I purchased an Ayre Acoustics QB-9 DSD because I wanted music and because I always wanted to try one.  It was a nice sounding DAC but IMO and based on my recollection, I would have taken the Hex if I were offered the choice of either.  With respect to full disclosure, I have never warmed up to Ayre's house sound and of the several Ayre pieces I have owned, all have been well-built and very clean and quiet sounding, but I ultimately replaced all of them with pieces I found to be more tonally dense and organic sounding. And the other side of that coin, I have owned 3 Metrum DACs.
Back to the Hex, with the highest respect to Eddie Albert, Eva Gabor and Arnold Ziffel, I find the difference between Hex and Pavane to be much greater than reported by acresverde, but that is my opinion of what I hear in my system.  The upgrade to Level 3 brings another level of clarity and spatial believability.
And finally, if I were in your shoes, I would be looking hard at the Onyx or, if I wanted to ditch my preamp and simplify my system, then the Jade.  Both use the new designed in-house Metrum Transient converter chips that are used in the upgraded Pavane and in the Adagio.
Good luck.
The Comet being discussed is quite far from the NOS sound. The two overarching characters of NOS are timing precision(could be called ease) and treble roll-off, the later being addressed by forward correction in many new production units.

The Comet has a slightly bottom up sound, a richness to it, which makes it pleasing to the ear however the timing performance is lacking due to the use of a minimal phase filter. Its worth saying that this trait may only appear in single-driver systems. I'd call it neither laid-back nor aggressive in sound though it definitely falls to the side of intense colors & slight rounding of the bass.

The only NOS DAC I've had my hands on, and its old outdated tech now, stayed in my system for years despite a raw, mean, lean sound. It's magic trick was proper timing. Instant transients. Microdetail.

The debate is going to come down to what you personally find more relaxing. I've heard a number of modern OS DACs pull off tube tropes: color saturation, fullness, laid-back. Think of NOS more like a widebander in that yes they can tame treble nasties but they're more there for the raw textures and timbre picky. Personally I find timing errors more annoying than any frequency abberations so NOS ends up the sound that calls less attention to the fact it all started as electronic pulses.
Red, everything you've stated is consistent with my research, especially about timing or "ease." Every pro and user review loves the Comet, but NOS seems to have what I'm looking for.
Right now, the Audio Note and Hex are the contenders. But I need advice regarding a high output DAC going direct into my tube amp (1V input sensitivity).
This may be a silly question, but is it helpful to use a reclocker before the input to a R2R DAC? I know the reclocking device should not do any upsampling.
Low, regarding a USB/SPDIF converter, I use a Audiophilleo2 with the Pure Power supply between my MAC Mini with Pure Music playback to a Bryston BDA-1. They have come up used here on AG ocassionaly. The AP2W/PP should be had for under $400 used. 
I believe your 1V input sensitivity means your amp/amps achieve full output power with a 1V input.  This is relatively low and should work with about any DAC.  To me, the bigger issue is matching impedance if you are adjusting volume with a passive device.  This can be a significant issue and is probably why I am an advocate of preamps, even though mine is adjusted for unity gain (and buffered).
For example, the Jade and the Adagio (both with onboard volume adjustment) output 2V single-ended (rca) and 4V balanced (XLR) with the volume control handled by adjusting the reference voltage, which does not affect the signal.  Only a few high-end manufacturers (I can only think of Metrum and Empirical Audio right now) offer this type of volume adjustment when going sans-preamp - directly from DAC to amplifier. 
How do you adjust your volume if your DAC directly feeds your tube amp?
I believe your 1V input sensitivity means your amp/amps achieve full output power with a 1V input.
@mitch2 , that's correct; 1V at full power. Regarding the Hex (2V unbalanced), I'm sure it will be a fine match as far as impedance and amp input sensitivity.
Let me give you the back-story, I'm using a PS Audio Nuwave DSD with 2.8V output and I believe it is driving my amp into clipping (sounds like distortion thru speakers). I have a thread posted about jitter control in which several members stated that I'm experiencing clipping due to the low 1.0V input to the amp. At first I thought the harsh sound was due to jitter, but overdriving the amp makes the most sense since it only happens on loud passages, such as a crescendo and close-mic'd brass.
My amp has a nice feature, a direct input with variable gain control; but only up to 1V max. Input impedance is 100 kohms.

I have an Atma-Sphere SE preamp that I take in and out of the system, and there is the same distortion sound during loud passages.
I actually checked other SE tube amps such as Quicksilver and CJ and they have 1.0 input sens. I guess when paired with a preamp with the right amount of gain, it works well.

I have been looking for a NOS DAC with analogue VC and haven't seen a suitable one yet. As far as the Jade and the Adagio, they would be ideal, but none are listed yet in the used market.
I appreciate you keeping up with me on this thread.


You should check out the new tube dac on the Doge site.  It's probably not NOS, but if it's related to the Doge6 CD player topology, I'm sure it sounds warm and grainless, which is what people who are looking for NOS dacs are usually trying to achieve.  BTW, IMO, looking for a dac based on circuit topology is not the best way to go about it.  Buy for sound, not design or specs.  But that's my opinion and, from what I'm reading around here lately, I stand with a very small minority.  Good luck. 

Lowrider - not a silly question at all. Jitter will be a problem unless you have a really low jitter source, like an expensive USB converter or network renderer, costing more than the DAC.

If you plan to use sources such as a transport or a Sonos etc., a reclocker like the Synchro-Mesh will bring that sound quality up to the latest technology uber-expensive DAC’s at a low cost.

You get the best of both worlds: analog sound of NOS, plus detail, dynamics and liveness of a low-jitter source.

I used to be of the opinion that resampling does some SQ damage to the datastream that cannot be recovered, but my latest Synchro-Mesh sounds almost identical to my best Ethernet renderer, which is 5X the cost of the Synchro-Mesh. My BNC cable is recommended with it because of the fast risetimes on S/PDIF.

Steve N.

Empirical Audio


lowrider57
  Seeking Advice on NOS DAC
Looking at this lowrider, this is also a R2R ladder dac you should look at for RedBook replay, not too much about it yet, but could be the new Yaggy
https://forum.audiogon.com/discussions/border-patrol-dac#1486831

Cheers George

@audioengr , I'm using a PS Audio PWT for 16/44.1 playback. USB from my Mac. SPDIF cable is 1.5m from Empirical Design. 
I'm wondering if any reclocking would be beneficial and if upsampling would hurt the native 16/44 input stream to an  NOS dac.
@georgehifi, Border Patrol has a good rep. I like seeing the quality parts being used, but no hirez from audio files?

@chayro , thanks, I'll check out the Doge. I'm not all about specs...R2R DACS don't really measure all that well. But they do have a nice organic sound.

@lowrider57 , Upsampling will not hurt, it will usually help, and most NOS chips support 24/96.  Simpler to filter this too.  Depends on the vintage of the D/A chip though.  If its a TDA1543 chip, maybe 44.1 would be better. 

You can also get the Synchro-Mesh in 44.1 flavor at minimal cost and select 16-bit.  Also great sounding.  I would recommend 24/96 standard version if the D/A supports it.  30-day money-back.

Steve N.

Empirical Audio

lowrider57
 I like seeing the quality parts being used, but no hirez from audio files?

But you did say in your first post. " I’m thinking NOS due to my large collection of Redbook CD’s."

To me pcm (redbook) once converted right, makes me think hi-rez is BS.

You can get discrete R2R ladder dacs, that can convert native DSD high-rez, but they are very expensive at the moment, but there are more and more coming onto the market, which could see the price come down.

Remember what MoJo Music says:
" When a PCM file is played on a native DSD single-bit converter, the single-bit DAC chip has to convert the PCM to DSD in real-time. This is one of the major reasons people claim DSD sounds better than PCM, when in fact, it is just that the chip in most modern single-bit DACs do a poor job of decoding PCM."  
  

Cheers George
That’s right George, Redbook is my priority. And I don’t wish to convert PCM to DSD. But the NOS DACs Ive been looking at will play 24/96 or 24/192 downloads from my hard drive thru USB. I know, I know it’s possible they won’t sound any different than 16/44.1.

Computer audio is secondary to me, but I’ve been adding music to my library. And some downloads are misrepresented as hirez, but I'd like to explore this new to me music.
That’s right George, Redbook is my priority. And I don’t wish to convert PCM to DSD.
Ok, look for dacs and cdp's that use the last commercial R2R Multibit from this list the Burr Brown "PCM1704"  (big so let it load and close popups)
http://vasiltech.narod.ru/CD-Player-DAC-Transport.htm

Or you can go discrete R2R.

Cheers George 
@jond, he didn't reply and the ad ended. I emailed the store and it's still for sale, so we will speak via phone call.
Jim
Digital Amplifier Company makes a very good usb-spdif converter. Tommy’s products are first rate, I’m listening to his HS Dac and like what I’m hearing. Had a couple of different NOS Dacs. One was a tricked out AN Kits 2.1b Sig loaded up with Black Gates, AN Sliver coupling caps, real AN IV transformers, 2w AN Tantalum resistors, with AN silver hookup wire, and excellent now tubes from Andy at Vintage Tube Services. Best dac I have ever listened to unfortunately I had to unload it back in 2010 when the economy went bad...Effing bankers!
@rodge, it sounds like you're saying the AN 2.1 Sig. is worth persuing.
I plan on asking if any of the high quality electronics were replaced under the hood.

Thanks for the tip on the usb-spdif.
Thanks @chayro . Looks VG for a good price.
I've been thinking about steering away from the ESS Sabre and looking for older multibit or proprietary processing such as the AN.
AN makes great stuff, but I think you're falling into the trap of believing the chip makes the sound.  I think it contributes to it, but I remember Lampizator taking apart some MHZS cd players that used the cheapest dac chip in existence and even he admitted that the player sounded very, very good.  I think part of AN's philosophy is to filter and alter the signal as little as possible, but I think there's more to it than just that.  Anyway, good luck. 

@lowrider57 , the best USB converter is the Berkeley. Find one used.

I have abandoned USB after doing 6 generations of interfaces. I even designed a XMOS galvanically isolated one like the Berkeley. Ethernet is superior for sound quality and setup. I have a DLNA Ethernet interface that works with Jriver and Audirvana and I’m working on a Roon-ready interface now.  They can use WIFI or wired.

Steve N.

Empirical Audio

AN makes great stuff, but I think you’re falling into the trap of believing the chip makes the sound....
I think part of AN’s philosophy is to filter and alter the signal as little as possible

I’m not at all saying the chip makes the sound. It’s just that I’ve had a couple ESS Sabre DACs and they seem to excel at retrieving detail, granted the implementation of the total component plays a part. I’ll add that I only have experience with $2000 and under DAC’s in my system.
In the dac’s that I’ve owned or auditioned, IMO, the analogue stage gives the component its signature sound. And less filtering in the digital and analogue stages helps.

I’m starting to like what I read about the Border Patrol. It’s possible that a good NOS DAC can reproduce Redbook plus 16/44.1 downloads better than than 24/96 files.
I do have one concern regarding the Audio Note, the AD1865, 18-bit Dac chip has long been out of production, so I wonder about service. Chips don’t fail very often, but I still think about it.

@lowrider57  I would not worry about the AD1865 chip, Audio Note is still using it and they have spares. That being said I just racked my brain and cannot recall anyone saying an actual converter chip failed on them. It must be an exceedingly rare occurrence.
@jond , yes you're absolutely right about that.
So, finally heard back from the dealer; waiting for pics of the innards. If all goes well, I'll make a purchase.