From further investigation it seems the module that died in one channel was the result of a power brownout (I'm assuming here as we have had several recently).
This seems to have caused an intermittent fault in the power supply I was using for the ProtoDac and I have recently tracked it down and repaired.
I've decided to beef up the supply and instead use a Salas-L-Adapter to power the Pi/Kali/ProtoDAC stack.
However, I noticed the Pi showing under-voltage during boot and excess heating of the L-Adapter during use so have returned to powering the Pi from it's official supply and the Kali/ProtoDAC from the L-Adapter.
From your recent post on voltages I was prompted to reread the Data sheet for the TDA1387 and noted the voltage range is specified at 3V-5.5V.
So I'm currently experimenting with de-rating and have reset the L-Adapter out to 4.85V.
Next step may be to power both the Kali and Pi from the Pi supply and the ProtoDAC from the L-Adapter and see what comes of de-rating lower.
Fun!
Thanks for the tip re cutting the old module before desoldering !.
I must have been overeager and in hindsight should have removed the output caps to allow cutting the module free...but thought that with so few pins soldered it would be an easy removal.
edit after listening...Heavenly!
I've felt that (Qualified!) -in my system- the ProtoDac can be a 'little' bass forward and 'smeared' at the bottom end.
Today it is so much closer to perfect that I am hesitant to experiment further with dialing back the volts..
My go to album is Jacques Loussier Trio 'Play Bach' (1959)
https://www.discogs.com/master/3394279-J...-Play-Bach
Today it is magnificent! The resonance of the lower registers of the piano ring out and the plucked string bass is fully there!
Where previously I dialed back the volume, today I pumped it. Detail, detail, detail and as Dick Shahinian said..
https://flic.kr/p/hsdndC
Find the original album as the later one here is too closed-in to be of use.
https://www.youtube.com/watch?v=9zO_v3HP7Wc
This seems to have caused an intermittent fault in the power supply I was using for the ProtoDac and I have recently tracked it down and repaired.
I've decided to beef up the supply and instead use a Salas-L-Adapter to power the Pi/Kali/ProtoDAC stack.
However, I noticed the Pi showing under-voltage during boot and excess heating of the L-Adapter during use so have returned to powering the Pi from it's official supply and the Kali/ProtoDAC from the L-Adapter.
From your recent post on voltages I was prompted to reread the Data sheet for the TDA1387 and noted the voltage range is specified at 3V-5.5V.
So I'm currently experimenting with de-rating and have reset the L-Adapter out to 4.85V.
Next step may be to power both the Kali and Pi from the Pi supply and the ProtoDAC from the L-Adapter and see what comes of de-rating lower.
Fun!
Thanks for the tip re cutting the old module before desoldering !.
I must have been overeager and in hindsight should have removed the output caps to allow cutting the module free...but thought that with so few pins soldered it would be an easy removal.
edit after listening...Heavenly!
I've felt that (Qualified!) -in my system- the ProtoDac can be a 'little' bass forward and 'smeared' at the bottom end.
Today it is so much closer to perfect that I am hesitant to experiment further with dialing back the volts..
My go to album is Jacques Loussier Trio 'Play Bach' (1959)
https://www.discogs.com/master/3394279-J...-Play-Bach
Today it is magnificent! The resonance of the lower registers of the piano ring out and the plucked string bass is fully there!
Where previously I dialed back the volume, today I pumped it. Detail, detail, detail and as Dick Shahinian said..
https://flic.kr/p/hsdndC
Find the original album as the later one here is too closed-in to be of use.
https://www.youtube.com/watch?v=9zO_v3HP7Wc
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bob
bob
