Mark IV Crackling on power up

[prm2770]

I read around and most of what i read lead me to believe that most noise such as this is generated in the preamp tubes. I changed all 5 out with brand new 12ax7s. Same omount of noise if not more and now I get alot of little high pitched pings when the amp is bumped or if you push/pull a know(are these the microphonics people talk of?). So I changed out all the 6l6's one at a time with an old set of tubes that I believe are still good. This made no difference in either problem. BTW the crackling and hissing does go away after about 2-3 min.

Any suggestions or is it time for the shop?

Phill

 

[Spewnz]

i had similar problems with my roadster when i took it to a shop they ended up replacing some pre-amp and power amp tubes and said some resistors and things were bad as well i would say trust in the mesa authorized techs.

 

[emperor_black]

Contact cleaner. Clean out your guitar input, send, return jacks. That should fix it.

Also try a different guitar cable.

 

[prm2770]

Thanks I will try it!