[hpsdr] Audio output noise

[Bob Stricklin]

Just some comments and more ideas for you……

I would focus on the TLV320AIC23B. This is the analog chip that is generating your sound. Inspect the soldering around this chip looking carefully at the ground connections. Also look at the bypass caps for this chip to be sure they look soldered properly and have no damage.

You mentioned that you still hear the noise with MUTE selected. I believe this indicates the source of the noise has to be from the TLV320AIC23B. A poor ground on this chip would likely yield the condition you mentioned. Bad soldering or a internal die bond wire issue may be causing the problem. If you have a issue with bypass capacitors, C46, or the VMID cap C34 you may be experiencing switching noise in the analog audio system. The TI data sheet may also offer some ideas on the problem.

Hope you are able to find the issue.

73,
Bob   N5BRG



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