Teufel IP 42 RC audio receiver with DC on its outputs (TDA7265)

[Kirkhaan]

I have here a Teufel IP 42 RC receiver that has about 150mV DC on the loudspeaker outputs.
The DC level is constant and does not change with volume settings and it is causing an irritant plopping sound when changing input source or when switching on/off.

It has the TDA7265 amplifier IC embedded and I am considering replacing it, since it must come from this end-stage IC I assume.
https://www.st.com/resource/en/datasheet/tda7265.pdf

Anyone experience with DC offset and TDA7265 amplifier IC's?

Thanks!

[Kirkhaan]

Well, I have replaced the TDA7265 by a brand new one (~€4), but the DC offset of approx. 150mV is still there...

Now I am a bit puzzled, because its inputs are AC coupled and there is no means (as far as I understand) to tune the power stage bias, see below application circuit, which is almost 1:1 implemented in the Teufel amplifier.



Anyone advice or suggestions? Thanks!

[DaJMasta]

You could just AC couple the output too, but isn't the popping usually due to zero crossings/spikes on the input?  Maybe you can add a few ms of delay before unmuting after initialization and switching?  Is the ground on pin 9 a good analog ground with your input source?

[Kirkhaan]

Thanks for your suggestions. They didn't make any difference unfortunately.
Its even there when the inputs are shorted to ground (and I've confirmed a solid analog ground).
The supply rail is perfectly symmetrical (+23.45 and - 23.44V).

It seems this 150~200mV DC on the output is the best this TDA7265 can do.

You could just AC couple the output too, but isn't the popping usually due to zero crossings/spikes on the input? 
Maybe you can add a few ms of delay before unmuting after initialization and switching?  Is the ground on pin 9 a good analog ground with your input source?

[Xena E]

It may* be possible to trim the output by applying a small DC offset directly to the input pins.

*Never tried it, just a thought.