Trouble on one channel (TE7022 + WM8716)

[Miles Teg]

Hello,

I got a problem on an audiophonics amplifier (TE7022 USB-I2S + WM8716 DAC + TA2020 Amp).

Suddenly the device lost one of its voice. (left channel). And on USB only. Amplifier with input on analogic RCA is ok on both channel.
On USB input, left channel is not dead but very quiet compared to the right.

I've check the WM8716 output, and clearly, with a 1kHz -20dB input from PC, right channel = 150mV, left channel = 5mV.

I've check power input of the WM8716 and I get the correct 5V on AVDDl and AVDDR, and 2,5 V on VMIDR and VMIDL.

Next step should be to check the I2S signal coming from TE7022. But that sohuld takes some times to solder good connection for the sniff (got an audio precision at work with SDIO input/output.)

Any advice of what could cause this problem?

Thank you. 🙂

 

[Miles Teg]

Ok, I've sniffed the I2S output of TE7022 and the data are evenly balanced between the left and right channel.
So I guess one channel of the WM8716 is dead.

Bad news as this is the 2nd amp (of this model) that failed like this (this is a returned device on warranty).
And I fear that if I replace the WM8716 it should fail again.

Maybe I should check the power supplies quality on oscilloscope.

What do you think could cause this failure?

 

[phase]

I have come to realize that the tenor TE7022 chip is pretty sensitive to esd, and is also now out of production.
The replacement has been one called SA9023.
That's frustrating for certain.

 

[Miles Teg]

(I could get some pieces from Farnell, I think I will replace it.)
Nope... I confused with the DAC...
So... this USB is screwed...

 

[phase]

24 96 TE7022L USB Card for DAC5 WM8741 WM8805 DAC Opt Coax | eBay

This may be a solution for you, with a bit of wiring into your setup.
There are schematics out there that will help.

Try searching for audio-talk WM8741, and there is a thread that has a pdf of a DAC schematic in it.
That schematic will have the pinouts for that little $20 board.

 

[Miles Teg]

Sorry, but I was a little confused, but the faulty part seems more the WM8716 than the TE7022 as this one has a correct I2S output. I will get soon replacement for WM8716 and check if there something wrong with it.

 

[Miles Teg]

Ok, nearly one year after my last attempt, I take back this amp out from dust. And now problem seems I get a shortage on the 3.3V line for USB and DAC with GND.

I'm now unsoldering components by compenents to find the faulty one.

 

[Joel Davidson]

Did you get anywhere fixing the lost channel on the wm8716? I have the same problem but on the right channel. Wondered if it was faulty de-coupling caps in the AVDDR supply line, or is the 8716 just knackered? Like you, this is the second amp I've had from Audiophonics. The first time it failed, I asked what the problems was, They said, It was a dry solder joint on the usb input chip, (the TE7022.) I checked that before i sent it back, It wasn't, so I don't think even they know. Unlike you, I don't have the means to test the 12S output on the TE7022 but if it's a simple case of component renewal, I can manage that. Anyway if you can throw any light on it, I'd be very appreciative.
Thanks.