Hi Nick! Buffalo DAC is very simple at it's core. Basically just the ESS chip, a good clock, power supplies, and very flexible PCB that allows all kinds of modding and connections. The Buff3 exposes even more of the features of the ESS chip, but is essentially the same as Buff2 when run in stereo, with same sound quality. Many people modding the Buffs will defeat the onboard switching power supplies in favor of high performance linear regulators like Belleson, Hynes or Twisted Pear's own Placid regulators. Solder holes are provided on Buffalo 2/3 board for external 78xx-style regulars. I don't know what clock and PS are used on EE, but they are more than adequate.
The big difference among all ESS based DACs, from Dragonfly to SimAudio Moon 750, is what happens to the analog signal after it comes out of the DAC.
The Sabre has relatively high current sourcing ability. iirc, It can make 1mA per leg, that's 4mA per channel when ganged into a stereo DAC. That allows the DAC to be run in current mode, which means playing into a very low resistance that would challenge most other DA chips. In this mode, the S/N is optimized. This is the method Twisted Pear uses in their own output stages like IVY and Legato. The drawback to these output stages like Ivy is that the designer judges opamps by the specs they keep, not the sound they make. Russ loves LM4562, the ultimate opamp, say John Atkinson another spec lover. It is the Bryston sound of suffocating feedback on a chip. I think the first version of EE came with these opamps, which is why rolling them became so popular.
The ESS chip makes something like 130dB+ s/n in current mode. But in voltage mode, it is still nothing to sneeze at, still much quieter than CD format which is 'only' 96dB s/n. So obsessing over current mode is not worth the effort imo, especially since it requires a current to voltage opamp stage, then a current buffer opamp stage. Going with voltage output opens up vistas for good sound that are not considered by Twisted Pear because they want that last -6dB of noise.
So to avoid the surface mount 4562s in the Twisted Pear buffers and take advantage of the decent current sourcing of the chip, I chose to let the chip itself drive the output through yummy Jensen 80% nickel core line output transformers. It sounds very good, but after a year it sounds too thin to me. So I am exploring active output stages for it now.
When I bought the Buffalo2 I also bought their Legato discreet output stage for Buffalo2, but never built it. So I will build that and see how it sounds. It has a true balanced output with discreet bipolar transistors. It uses the lovely LM4562 for balanced to single ended conversion to make an RCA output, but the BAL>SE feature can be omitted when you build the Legato. I could change the surface mount 4562 opamp to another for the SE outputs, or use my transformers to do the BAL>SE conversion. The nice thing about Legato is that it can source 150mA (!!!) so it can drive my 30 Ohm headphones too. I don't know if it sounds good, but we'll find out here shortly.
My buddy Carlman also uses this same DAC arrangement, Buffalo2 direct to Jensen line output trannies. But he runs his DAC into a tube preamp which buffers the current and sexies it up a little before heading off to his amp, and his amp is a tad warm and big bottomed anyway, so his does not sound thin at all. My amp is very flat and clean, so the source needs to carry its own water. My tuna and phono sound great.
Another option I can use is a simple opamp current buffer, either single ended direct outputs, or driving my the Jensen transformers. My friend Sol recommended ST Micro MC33078 opamp. He is designing a simple output stage circuit with 6dB gain to get the ESS chip's voltage output up to the standard 2Vrms. I have never run out of voltage with the chip alone, but I have come close when playing symphonies with very quiet passages. I'll need to make a +/-15V power supply for the opamp, but it's otherwise very simple and should sound good, maybe better than the 4562 on the Legato.
Third option is one that I have been thinking about for a long time, waiting for about 50,000 pennies to overflow out of my piggy bank. It is a
tube output stage that I found on a forum a few years ago. 6N6P tube into Sowter output transformer. It is ultra simple, and should sound very good. I think Lampizator uses ESS DAc with 6N6P output, and significant tweaks everywhere.
I haven't heard any complaints of thinness from EE DACs, and it is not surprising mine sounds a bit thin with trannies only, especially super low distortion trannies with minimal glow.
I have an old Buffalo32 that I haven't used in a long long time. It needs a new home. It has Volumite, and the standard Twisted pear series regulators at that time, not shunts, not Placid. With the Buffalo32, no mods to the output stage or the on board regulators can be made unless you can do tiny surface mount work. But the main regulators could be upgraded to Belleson 2A reg which would probably improve the old style Twisted Pear regs. Buff32 has the current mode output stage with current to voltage converter and current buffer opamps (LM4562.) It is not the ultimate Buffalo build, but it was head and heels better than my previous Altmann battery powered DAC which I dumped immediately after I fired up the Buff32. It is on my long list of audio things to sell. PM if you are interested.
Sorry for the rant about *my* stuff, but you are interested in Buffalo so now you have the benefit of my Buffalo experience and ongoing exploration. I love the chip for the naturalness of non-oversampling DACs like my previous Altmann, but also the tonal balance and wide, clean FR and excellent jitter reduction. I am still committed to getting the best out of it. I am also considering going to Buff3 so I can get 8 channel output, and feed it with Exadevices USB board, or just buy the ExaSound 8 channel complete DAC. They also make a stereo DAC worth checking out.
http://www.exasound.com/If I got tired of it, I would try the Ayre USB DAC, but it has no digital audio input, only USB, so you need a computer. It has a unique output filter which eliminates the pre-ringing to make a very natural, analogish sound. People whose opinion I trust love this DAC and it's sister CDP. I myself, have not heard it yet, so take my enthusiasm for it with a grain of salt. I have heard the top Antelope Gold and the bottom Black, both with and without the Voldemort power supply. It is the most awesome DAC I have ever heard, but it is very stimulating. It is not a kick back and enjoy, natural sounding DAC. It is a grab you by the throat and go on an adventure of a lifetime DAC. Very powerful transients, very pure detailed tone, great bass, etc. Antelope probably has the best digital stream reclocking on the market, I think that's a big part of the goodness. But you gotta be a real hard core audiophile to like it. I prefer more laid back, more natural, emphasis on the music rather than the excitement of the sound. But the Antelope is very exciting if you like adrenaline fun from your audio system.
Holy shit that's long!! Like the old days!
