Just got all new JJ tubes both power and pre amp in my blackstar ht40. I just tried it out at home and im getting a lot of noise/buzz in the overdrive. This never used to happen. Does anyone know what could of happened? Should I take it back (Sam ash). The tech is a reputable tech from what I hear around town.

Last edited by JJbonesaw at Jul 15, 2015,
Start with the preamp

Get a block diagram of the tube order

Starting one at a time swap preamp tubes back with their originals

Then swap tube positions in different patterns. This is if they are all 12A(x)7s

Mark the tubes with a sharpie if you have to but keep track of the tubes or you will quickly get confused.

If you have a contact cleaner, like Dioxit, spray all of the tube pins at least once as you do this exercise

Do all the tubes light up normally

If it still persists, then let us know

Also, has anything else changed
Last edited by 311ZOSOVHJH at Jul 15, 2015,