Problem of whistling in the subwoofer, after repair spl dynamics D7

[nhervus]

Hello,
I have a problem of whistling in the subwoofer, after-D7 repair spl dynamics.
The amplifier works fine after repair (Irf360LC, DWM4070NV driver card rehabilitated, and some other components).
But there is a variable whistling in the subwoofer.
I think a capacitor is responsible for this problem, but I can not find.
Have you ever encountered this problem?
All help would be welcome.
Thank you in advance.

 

[Perry Babin]

If the noise is at a very low level, it's likely due to un-synchronized oscillators (power supply vs output stage). It will sound similar to the audio file below:
http://www.bcae1.com/temp/cooleditmixedoscillator01.wav

 

[nhervus]

yes it is the noise, you'd have an idea to synchronize power supply output vs internship, please?
By heating the driver card a bit, the sound changes.
A capacitor would it cause?

 

[Perry Babin]

The sound changes because heating/cooling causes the frequency to change.

This isn't generally a problem that can be repaired. It's a design issue. For the most part, playing through a heavy subwoofer which will be well away from the listener makes the sound inaudible in normal use.

 

[nhervus]

Ah ok, I'm sad not to be able to do better. But never mind, I have rehabilitated another amp.
Thank you for answering my questions, that's nice.