Dear team,

I have got a problem with my Buffalo IIISE DAC. The last days I opened my DAC and added another source to Buffalo input (I²S) (that board I added is a Texas Instruments evalution board) but since that time the sound quality is rather bad (also old SPDIF source), it sounds like "depressed", narrow, the opposite of highend, but there is no serious noise or anything like that. The Texas Instruments board works, also they work together, I can play audio via SPDIF in and I²S in. But sound quality of both is bad.
The second thing I noticed: I had made it possible to switch between shunt regulator output and LiFePO4 3,3V battery for Clock and DVCC circuit. When I switch off the power for DVCC now (so neither Trident nor battery), the "lock LED" doesnt go off completely as it used to do, it still flickers a very very tiny bit. Sometimes brighter, sometimes audio passes through for a view ms. And I measure about 2,18V on the "out" pin of Buffalo board DVCC. (To be 100% sure you understand what I mean: I mean the input of Buffalo board, where usually the regulated 3,3V of the Trident "go in").

I have disconnected TI board completely and made everything what it was before - no chance. All power supplies seem to work fine, except the dual shunt modul measures 3,60V on it's output, that's truely a bit high no? I have got the older version of dual shunt also, that one measures 3,51V with the same bad sound a strange DVCC behaviour and flickering "lock"-LED.

Can anyone help me? Tell me what I could measure? Or is it for sure broken? Do I have any chance you could repair it, that I send it to you?

Thank you very much for your time and help,

Best regards from Austria,

Florian

Sorry for the late response. You could start by (extremely carefully) checking all of the supply pins of the ES9018.

If I were to guess I would say one of the op-amps that supplies AVCC has died.

I'm sorry - I misread that part - 3.6V out is just fine for AVCC - actually anything from 3.2V to 3.8V would be ok. But you need to be sure you don't have any dry sockets and that the voltage is actually getting to the DAC. You might just go over all of your solder joints very very carefully.

Hi Russ,

unfortunately that didnt help. I resoldered all my joints, nothing changed. - I am not sure if you understood me right what my problem is. The point is, that even when I disconnect the trident output for DVCC at all (!), the board sometimes get the necessary supply and audio is played back. Why that? How is that possible? Do you have any more hints? And would it be possible to send you the board, do you do repair works?

Thank you,

Florian