Several months ago, I posted about
the tda1387x8 NOS DAC. If you're willing to do a few simple mods, I still think this is a "diamond in the rough", as your all-in cost should be around $150 or so, but the performance is dramatically better than the price might suggest. That in mind, there are a few limitations of the tda1387x8: higher resolution formats simply won't work. I think you can go a bit above CD 16/44; I forget the cutoff, but certainly modern super-high sample rate / wide bit rate stuff won't work. Also there's no volume control. (The volume control certainly doesn't have to be in the DAC, but that's where I personally want it.)
Enter the
Soekris dam1021. This is, fundamentally, an R2R DAC board. But it also has, on-board, an FPGA which performs inbound signal re-clocking, and also user-modifiable digital filters (run it in NOS mode, or choose from the dozens of community-developed filters, or write your own). It supports I2S or SPDIF input, and even DSD. Output is single-ended, or balanced (stock balanced uses opamps; advanced users can parallel two boards and get "native" balanced output).
Some DIY is required. However, in my opinion, one of the best features of this DAC is its flexibility. You can build a very minimal system with only cursory DIY knowledge (experience hacking on the tpa311x boards is sufficient); or you can go nuts with a level of fanciness limited only by your imagination.
Here's the absolute bare essentials for a minimal/simple build. The prices I list include shipping to the USA (and are from memory, might be off by a buck or two). Besides the board, you really only need two things: power and input.
- Actual Soekris dam1021 board: $280 for the 2% version, or $210 for the 5% version.
- Power supply: Antek AN-0107 Transformer: $18
- Input: various ebay options: $20
Total is $318 or $248 depending on which board you get. It comes with XLR connectors. I'm assuming you already have wire and RCA connectors on-hand, and can recycle an enclosure.
The optional volume control requires only a basic 10k linear potentiometer, which is $5 for a cheap one or $15 for an overkill pot.
Or you can do volume control through the serial port, in which case you might need to spend another $10 or $15 on a serial (or serial-to-USB) cable. But you don't
need to do volume control on this device, you can still do it in another device.
Most of the builds I've seen on diyAudio are
slightly fancier. At a minimum I'd get a decent input device. The DIYINHK XMOS USB-to-I2S is $66 shipped to USA, and is pretty popular. Even with that, you're still under C&C price guidelines.
FWIW: I used an Amanero USB-to-I2S device, which IIRC was about $100. I bought a nice R-core transformer from eBay for about $30, and a DIYINHK +/-12V super-regulated power supply for $60. Ignoring the case, my all-in cost is pushing $500, which is over C&C guidelines, but I'm really not that far from the super-simple build described above. And where else are you going to find a true R2R DAC for anywhere close to this price?
Given the flexibility of the device, you can start cheap and go from there.
There are several great links that serve as both a good introduction and fairly detailed user manual:
So, after all that, how does it sound? I have no complaints! I haven't yet had a chance to compare it to the tda1387x8 directly. But from my "aural memory", they are in the same league. Also, to be fair, I never did the "next-gen" mods on the tda1387, so I probably left some improvement on the table... someday I might still go back and give those a try. But I'm also enjoying the dam1021 quite a bit, and am already wanting to do a second "advanced" build using two boards for native balanced output (and also integrate a Raspberry Pi into it, to make a fully-featured music server).
No affiliation with Soekris. Just trying to throw some non-standard DAC ideas out there for the C&C community!
