When it comes to DACs, I've always used the more modern, and generally more readily available, sigma-delta (SD) variety. The other variety, loosely speaking, are the non-oversampling (NOS) types. Original DACs (going back a few decades) were actually all NOS multibit types. But based on what I've read on the Internet, multibit NOS DAC chips are harder to design and manufacture, so SD has all but taken over in terms of availability and (in most cases) affordability.
Initially, I used only SD DACs because I didn't know the difference between SD and NOS. When I read of the difference, I also started seeing that NOS has a pretty dedicated fan base. From what I've seen, there's not a lot of "value" NOS DACs, they tend to be either super cheap or super expensive. My first foray into NOS DACs was with the Muse tda1543 x4 DAC, a $50 direct-from-China ebay job. I was immediately unimpressed, and gave it away.
Still wanting to know what all the fuss is about, I took a chance on this tda1387x8 DAC after reading
this thread on diyaudio. See also
abraxalito's blog entry on it.
Out of the box, this thing was OK. Not offensive, like I found the Muse tda1543x4, but nothing I'd want to listen to at length. So the first order of business was to drop in better op-amps. I used the AD845, as suggested in the diyaudio thread by abraxalito (specific part number: AD845JNZ).
Immediate improvement. At this point the DAC was very fun and pleasing to listen to. I could still hear a few weak spots from time to time, but nothing that distracted from musical enjoyment.
Swapping opamps in this DAC requires no special tools (i.e., no soldering). Just a screw driver to take the top off the top half of the case. Needle-nose pliers will make the opamp swap easier, but you can probably do it with your fingers, or even household tweezers. And I think at this point, the DAC is good enough for most people to see what all the NOS "fuss" is about.
Since then I've done a few more straightforward mods, though these did require a soldering iron: (1) replace the pin7 SMT ceramics with 2x 470uF caps on the bottom of the PCB, (2) remove the 2n2 opamp feedback caps, (3) increase size of capacitor for DAC chip supply (from 220uF to 2200uF), and (4) increase analog stage decoupling. The details for these mods are given in the diyaudio thread. For those of you who were able to comfortably hack on the tpa311x amps, these mods are no more difficult.
According to others in the diyaudio thread, there's still some gains to be had with further modding of this DAC. I've got about $150 into this DAC so far, and it's definitely the best DAC I've heard so far at this price level. It
may be the best DAC I've ever heard... to be fair, I've never heard any fancy megabuck DAC, as I've always tried to play in the value space. The most expensive DAC I've heard is the Gustard DAC X-12 (ES9018 based), which I received just a few weeks ago via Massdrop. It sounds nice enough, but there's something about this tda1387x8 that's just so much more
fun. Maybe it's the DIY bias? But I really think my speakers sound like they've grown in size by at least a factor of two.
An important heads-up for anyone who wants to give this thing a try: by default it expects 220v mains, so, straight out of the box, it won't work in the USA. To get around this, I'm using this
Goldsource STU-200 Step Up/Down Voltage Transformer - AC 110/220 V - 200 Watt. You will get a 220v version if you buy from
Taobao or
Cart100. Note Taobao and Cart100 offer the fully built version ("Black") and the parts-only kit version ("Blue"). The parts-only kit version is the much cheaper one (and doesn't come with a case, heatsinks, or any transformers). Since I got mine, seller
doukmall on Ebay will sell a 110v version as long as you ask. I'm working with my Taobao agent to see if I can get the 110v version direct, since it's a little cheaper to go through Taobao (even with the agent fees).
Ever since I started playing the tpa311x amps, I've been looking for a DAC equivalent. By that I mean, a new level in
value, i.e. performance per dollar. At this point I think I've found it. I hope some other readers of this C&C board will get some enjoyment out of this DAC.
