[IDEA] Upgrading my DAC Hat

[Tim Curtis]

Would you care to post a detailed build thread for that ?
I have an ancient Phillips cd-650 c/w TDA1541 and would be interested to reuse.

It will not work with the TDA1541, which is much more complicated and has greater parts and power supply requirements. On the TDA1387 x 8 module, of the 28 pins, only 7 pins are actually connected (I2S, V+, GND, Left out, Right out).

I can post the pictures of the top and bottom of the board for the TDA1387 x 8 module, if interested. It is very simple. The I/V conversion process is passive. There is no filter on the output. 

It is possible to use upsampling in Moode using SoX up to 384k, but I have found that the native bitrate always sounds better than the upsampled. I think this is due to innaccuracies with SoX, even with the highest quality settings.

I have upsampled a few files using PGGB with millions of taps to 16/384, and I cannot hear a difference from the native bitrate file.

The DAC is limited to 16 bits. It can play 24 bits, but truncates the least 8 significant bits. It still sounds great.

The TDA1387 is a very interesting design. The end of the multibit era. It uses continuous calibration of the five most significant bit current sources, so it has 32 current sources and one spare source. Philips multibit DACs are also unique in that they do not use resistors like the Burr Brown DACs, but use active devices to generate the currents.

The 1387 is legend for NOS designs when implemented well.

Consider offering some pre-built DAC boards. I'd definitely buy one.
Is it a HAT form factor?

-Tim