Sweep Noise in GSSL with turbo

Hi Guys,
I have a problem with my Gssl that's working well since two years.

There is an occasional sweep noise on both channel in same time . this noise change in frequencies when i turn the Threshold control and after diseapper.

It seem's coming from the sidechain section.
The noise stop when i unplug the -12v 0v +12v connector of the turbo board or if i remove one of the two LF347 or the LF353

I recorded this noise, you can hear  it here:

https://www.yousendit.com/download/WUJhZEUzT2JLVlVkVU1UQw

Anyone have an idea?

Thanks

Marc

The problem is solved now. Actually it was a bad working TL7812.