Warwick Thumb Bass Pre-amp noise

[goingdownslow]

Haven't used my '90 Thumb Bass for a while and when trying it today, when I inserted the jack plug there was a static type electrical noise, like something being turned on, it lasts two to three seconds and then all is fine. It will do it again after removing and re-inserting the plug. It never used to do this and my other Thumb Bass, a '91, doesn't do it. A new battery doesn't help.

[paul_5]

Is it not just the capacitors/opamp filling up after being empty?

 

[Hellzero]

The output barrel jack may be loose (inside), as it's a typical problem with these.

 

Or it could be what @paul_5 said, so check after a few minutes of playing if it does that static noise again, if not, @paul_5 was correct, if it sill does, get a new barrel jack.

 

Buy these as even the expensive Switchcraft don't last (I've tried so many until I found these that last very long): https://www.amazon.co.uk/Alnicov-Stereo-Copper-Guitar-Cylinder/dp/B08L69K6QH/

 

[goingdownslow]

Barrel jack appears to be ok.
Left it plugged in for 30 mins and it still does it when reinserting the jack.
Disconnecting and reconnecting the battery whilst the jack is in has the same effect.
Doesn't do it in passive mode.
Once it has powered up it is quiet and functions as it should, so I will live with it.