+- Moode Forum (https://moodeaudio.org/forum)
+-- Forum: Audiophile (https://moodeaudio.org/forum/forumdisplay.php?fid=32)
+--- Forum: Audio gear (https://moodeaudio.org/forum/forumdisplay.php?fid=10)
+--- Thread: ProtoDAC TDA1387 X8 project (/showthread.php?tid=5531)
RE: ProtoDAC TDA1387 X8 project - hifinet - 11-04-2024
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.
RE: ProtoDAC TDA1387 X8 project - eculcea - 11-09-2024
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.
RE: ProtoDAC TDA1387 X8 project - hifinet - 11-11-2024
(11-09-2024, 01:29 PM)eculcea Wrote: 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.