ProtoDAC TDA1387 X8 project

[Skip Pack]

Sorry for the dummy post above!

Good info on the supplemental caps. I'll give it a try on my next (soon) build. A question for a bit of context: I'm assuming that the two electrolitics are in parallel forming a compound capacitance? So any bypass is bypassing both electrolytics and the only complicating issues might be the short leads and traces combining them? Is it safe to say that any combination of 1+ capacitors at or somewhat less than 2K uf meets the general electrical design need?

I, too am using a filter, the realtively new Pass full range active EQ board and it complements the DAC nicely allowing a better match with the Alpair 11MS drivers in small Nostromo boxes. I may flatten both the LF and MidHighF components slightly, but it's fairly close.

Thanks,

Skip

[hifinet]

The two electrolytic capacitors C3 and C4 are in parallel, and the total capacitance is C3 + C4. Yes, any combination of 1+ caps for 2000uF total, but 2000uF total is just what I think sounds good in the circuit. Others might like more or less total capacitance, and different capacitors. There is a limit in terms of the available space, but I would encourage some experimentation with C3/C4, as the sound can change considerably.

[hifinet]

ProtoDAC on the YouTube Gabster channel for DIY audio.

[Tim Curtis]

Very cool review with an excellent characterization of ProtoDAC and it's performance in different configurations :-)

[hifinet]

My usual Chinese module suppliers suddenly seem to be out of stock. Hmmm...

[DRONE7]

Supply-Demand-Promotion-Manufacturers realisation of the asset...tap turned off ?

[Tim Curtis]

My usual Chinese module suppliers suddenly seem to be out of stock. Hmmm...

Looks like no hits on AliExpress based on a quick search but the part is still available on eBay
https://www.ebay.com/itm/354649097971

[hifinet]

Supply-Demand-Promotion-Manufacturers realisation of the asset...tap turned off ?

Yes, for now. Apparently he is reassessing the market, based on his response.

[fdealexa]

Hi Mark, hi everybody, 
This is not related to the component shortage: I wish to informe you that I have seen a version of "parallel TDA1387" made with 4 IC only, but with discrete components instead of SMD components. I am trying  to buy a couple of them (to be wired in parallel) to test if those capacitors "sound" better. At the moment I have not been lucky finding them: may be that your chinese supplier knows how to find them, or somebody else, in the forum, can help in this way.
Best regards and thanks,
Francesco
   

[hifinet]

Hi Mark, hi everybody, 
This is not related to the component shortage: I wish to informe you that I have seen a version of "parallel TDA1387" made with 4 IC only, but with discrete components instead of SMD components. I am trying  to buy a couple of them (to be wired in parallel) to test if those capacitors "sound" better. At the moment I have not been lucky finding them: may be that your chinese supplier knows how to find them, or somebody else, in the forum, can help in this way.
Best regards and thanks,
Francesco

I bought one years ago. I never used it. Still have one. I have not seen them for sale in quite a while.

Changing the SMD caps on the X8 module is well beyond my capabilities, but they do make film acrylic SMD 1uF caps in 1206 and 1210 sizes. Even those seem too big.

Another thing to try is to eliminate the 1uF pin 7 caps entirely by just clipping them off (the larger C2, C4, etc). Abraxalito omits the cap on his TDA1387 designs.

The other caps are the 100nF power supply decoupling caps, and MLCC are supposed to be optimal for that application.