63 Vibroverb bias vary trem motorboating problem

[Victor Denance]

Hi!

I have a motorboating with my 63 VV replica's trem.
It's a "flupflup" pulsating with the trem. It starts when Intensity is set to 4 and increases when turned up, and when Speed is set between 3 and 7.
Otherwise the trem works fine.

I replaced the tube, checked my lead dress, and redid the solder joints with no success.

May you help me pinpoint the problem?

Thanks!

[txstrat]

How hot have you biased it?
Since the trem changes the bias to the hotter side when engaged, it might be too hot. I would say a slight "flupflup" is normal.
Just a thought.
That doesn't explain the behavior of making the unusual sound only between speeds of 3 and 7, though.