ProtoDAC TDA1387 X8 project

[hifinet]

The phase shift at the corner frequency is 45 degrees. The ideal phase shift at 20 Hz is 0 degrees, but that is not possible. Once you add a first order high pass filter with the capacitor, it will cause a phase shift in the entire audio band (although it is very low and insignificant at 20kHz). The goal is to minimize the magnitude of the phase shift in the audio band.

[eculcea]

It looks the more TDA1387 the better. I think physically I could solder another 8 chips adapter on top of each other to make it 16 chips, from electronics standpoint would this work?
I am a hobbyist learning about audio electronics and maybe this is a dumb question.

[hifinet]

It looks the more TDA1387 the better. I think physically I could solder another 8 chips adapter on top of each other to make it 16 chips, from electronics standpoint would this work?
I am a hobbyist learning about audio electronics and maybe this is a dumb question.

Yes, it works. I removed all of the pins from two modules, and then soldered 7 wires (pins 1, 2, 3, 5, 6, 25, 28) connecting the two boards to the PCB. The IV resistor needs to be reduced in half to about 210R (or less than 215R), since the current will be doubled. This will reduce noise by another 3dB, and also reduce the output impedence. I think the power supply decoupling capacitors will need to be doubled.

I did not hear much of a difference in sound quality, but there were some limitations in that I used standard metal film IV resistors, and I didn't double the decoupling capacitors.

[dwhacks]

So I've been using my Protodac with moode for quite some time, and its excellent! I had enough parts to build another, with some different caps and an rpi Zero 2 W, so I figured I would do that and us raspotify for a garage/outdoor player (I know I know, no lossless from spotify).

My question, is does anyone know how to invert polarity there? I don't want to do it at my speakers because I use different sources sometime, so it would be best to do it on the pi, like done with Moode and CamillaDSP.

I think I should be able to do it with ALSA, but I have no idea where to start, and googling made me even more confused!

[hifinet]

So I've been using my Protodac with moode for quite some time, and its excellent! I had enough parts to build another, with some different caps and an rpi Zero 2 W, so I figured I would do that and us raspotify for a garage/outdoor player (I know I know, no lossless from spotify).

My question, is does anyone know how to invert polarity there? I don't want to do it at my speakers because I use different sources sometime, so it would be best to do it on the pi, like done with Moode and CamillaDSP.

I think I should be able to do it with ALSA, but I have no idea where to start, and googling made me even more confused!

For a garage/outdoor player, I doubt that you can hear the difference with inverted polarity. 

Raspotify says "If you’re looking for a turnkey audio solution for Raspberry Pi’s with Spotify Connect support we recommend moOde™ audio player."

[dwhacks]

That's probably true, but I still would like to have things "right". I could run Moode, but lately the spotify portion of it has been crashing lots. At least the latest release has an auto-restart for the service, but still its not super solid. Raspotify seems to have less issues, and I just assumed a more simplified player would run better on the Zero.

I'll keep diggin.

[Lolkapies]

After changing cheap WIMA and Mundorf MCap capacitors to Jantzen Audio Superior Z-Cap magic happens, the sound has gained an additional dimension, these capacitors are very musical.

Now I would like to use good I/V resistors, will Charcroft Z-Foil 430R be good, have you tried other precision resistors like Vishay Sfernice precise 0.01%. Will there be a big difference compared to Dale metalized resistors?