A simple opamp swap was the very first mod I did to the x8 dac (didn't change anything else) . I noticed an improvement, but it was akin to only dipping my toes in the water... Subsequent mods were like diving in all the way, if you catch my meaning.
What is the design difference between this DAC and the one in the following link? Would this DAC be capable of something like this or is this already how it functions?
Building the ultimate NOS DAC using TDA1541A
Building the ultimate NOS DAC using TDA1541A
The TDA1541A is pretty much the 'reference' multibit DAC, but its rather expensive and very power hungry and something of a devil to get right in terms of implementation (layout, decoupling, DEM tricks). If you're looking for something more affordable and less easy to screw up as a DIYer, I reckon the TDA1387 is it. They both share Philips' dynamic element matching architecture - in the TDA1387 they call this 'continuous calibration'.
My thinking too - that it would be good enough to start with. I've stuck with it for a few years now and not felt an urge to move on to better things, rather my DACs were limited by implementation details I'd overlooked. Now I reckon I've fixed those and the TDA1387 is fully satisfying. Of course its not doing 192k in my designs (though it can) and nor is it doing 20 bits, so if one has material that calls for those, then in and of itself it may not be enough. I reckon though by using 16 chips in parallel it might well do 20bits - something I have in mind for the future when I have a DSP in my DAC....
Hi.
Has anyone used these ?
4X TDA1387 Parallel Transfer Board Audiophile HIFI DIY sound close to TDA1541 | eBay
I've ordered 4 of them ( not arrived yet ).
Andy
Has anyone used these ?
4X TDA1387 Parallel Transfer Board Audiophile HIFI DIY sound close to TDA1541 | eBay
I've ordered 4 of them ( not arrived yet ).
Andy
Attachments
That plug-in looks to come from the same vendor as makes the completed DACs. Here on Taobao there's a schematic - https://item.taobao.com/item.htm?spm=a1z10.5-c.w4002-2328342454.34.Msnc8I&id=41769520252
Yay, my '8X TDA1387 DAC' arrived today. I picked it up from the post office then had to go straight to work, so I haven't plugged it in yet. Since I had them add the CM6631 USB card I also bought a raspberry pi 2 and installed MOODE audio player. Ill check back in later to report my experience with that. I also got some AD845JN(s) which i want to swap with the built-in ones asap, but i guess I should at least hear it in stock form first. Im really excited to check out this DAC.
Okay, well unfortunately enthusiasm does not equate to functionality. I was so excited to get my new DAC setup with my new Rasberry Pi2 and MOODE audio so I spent a bit of time getting it all setup last night (with some issues with the Rasberry Pi, but that's for a different thread) and presto... static... Hmmm? So I thought, okay maybe there is a problem with the USB card on the DAC. I removed the card and plugged in the optical port from the output of my computer. (That is the way I have my system setup through a different DAC and it works great.) At first it was pretty glitchy, loosing clock every few seconds, but eventually after a bit it seemed to stabilize. I would still loose sync every say 30 seconds or so but I was able to listen to a couple songs. I played my 96k versions of Kind of Blue and Superstition. I really liked the sound of the DAC, but could totally hear everything I'd read about it unmodified. I thought well at least lets upgrade the op amps and pull the 2n2s. I did and was pleasantly surprised at the difference it made. I actually kinda missed the harshness the 2n2s added but knew that it wasn't accurate so I am happy with the sound. Now what do I do about the sync?
One thing I noticed was that the DAC would loose sync whenever I would mess with the power somewhere. Like if I unplugged something from the same strip, or power cycled my amp. It wasnt consistent but made me curious so this morning before leaving for work I tested the power on the board. I got some very confusing results. I tested the 5v, +15v, & -15v, points and got 0v DC and got 8v AC on each of the 3. I must have done something wrong, but was running late so... Advice?
Edit: FYI this was modified for 110v power
One thing I noticed was that the DAC would loose sync whenever I would mess with the power somewhere. Like if I unplugged something from the same strip, or power cycled my amp. It wasnt consistent but made me curious so this morning before leaving for work I tested the power on the board. I got some very confusing results. I tested the 5v, +15v, & -15v, points and got 0v DC and got 8v AC on each of the 3. I must have done something wrong, but was running late so... Advice?
Edit: FYI this was modified for 110v power
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Just some super simple suggestions, maybe stuff you've already tried:
- reseat the power cable in the IEC, i.e. where the power cable meets the chassis. I've had strange issues a few times that were caused by the power cable not being pushed all the way in.
- try another AC outlet, one that you know is on a different circuit.
- you might want to try running a wire between the IEC ground and the chassis. I'm not sure if it was this thread or the other tda1387 thread, but I was recently discussing some issues that suggest the chassis isn't properly grounded. I haven't done this to mine yet, but planning on it.
- did you happen to try that input select button on the front of the unit? I find music still comes through even when the wrong input is selected, but will sound garbled.
- can you try some redbook 44.1/16 source material to see if that works any better? I have some 96k stuff that works, but IIRC, I had trouble with higher rates.
Sorry if you already thought to try all that, just throwing out simple ideas (because that's all I have!).
Let us know if you make any progress.
- reseat the power cable in the IEC, i.e. where the power cable meets the chassis. I've had strange issues a few times that were caused by the power cable not being pushed all the way in.
- try another AC outlet, one that you know is on a different circuit.
- you might want to try running a wire between the IEC ground and the chassis. I'm not sure if it was this thread or the other tda1387 thread, but I was recently discussing some issues that suggest the chassis isn't properly grounded. I haven't done this to mine yet, but planning on it.
- did you happen to try that input select button on the front of the unit? I find music still comes through even when the wrong input is selected, but will sound garbled.
- can you try some redbook 44.1/16 source material to see if that works any better? I have some 96k stuff that works, but IIRC, I had trouble with higher rates.
Sorry if you already thought to try all that, just throwing out simple ideas (because that's all I have!).
Let us know if you make any progress.
Yes that is correct. I have used the USB and the toslink optical but not the coax. I will setup my focusrite and test that tomorrow hopefully. The USB was far worse than the optical but both had similar issues. As I mentioned earlier the USB issues may also have been related to a raspberry pi I was using. That's why I used an entirely different signal path and tested the optical.
Well that didn't quite work the way I thought it would. Please see my answers below that are a quote within a quote.
I just took some measurement and found that the reason I wasn't getting any DC readings across the +\- 15v and the 5v to ground is because the board isn't grounded. I measured across some resistors and got 4.9v and 30v across the+15v and -15v so it appears that everything is working properly after all.
I finally got a chance to test the DAC today. I am experiencing the same problem using both the optical and coax as well and using the USB port. I also tried another computer entirely. It clicks and pops and occasionally the sync light briefly turns off (although it stays on with the USB port). So it seems as though there is something wrong with the DAC. I would return it but I'm sure I voided the warrant already. Plus, what's the fun in that? I basically bought this things for its parts. Any suggestions?
I checked into the input side circuitry, nothing untoward noticed there.
Sounds like you've got a problem with common-mode noise. So exploring grounding options I reckon is your best bet. The DAC's 0V is connected to the coax input, USB input and the analog outs. Is your digital source, or your preamp grounded (connected to mains earth)?
Sounds like you've got a problem with common-mode noise. So exploring grounding options I reckon is your best bet. The DAC's 0V is connected to the coax input, USB input and the analog outs. Is your digital source, or your preamp grounded (connected to mains earth)?
I started a new thread for my sync issues:
http://www.diyaudio.com/forums/digi...-tda1387-8x-dac-sync-problem.html#post4553356
http://www.diyaudio.com/forums/digi...-tda1387-8x-dac-sync-problem.html#post4553356
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