odd sound

[maliciousteve]

Hi guys. I got my Powerball yesterday and when I use the high gain channels I get a sort of crackling sound coming through the speakers. I know it's not the cab because I put the head through another cab and it done the same thing. I've not come across this before but could this be a sign that a preamp valve is on its way out?

[indysmith]

Crackling and popping is usually associated with power tube wear.

this is off the MESA site and is always useful;

Signs of Wear
Power Tubes:
•  Low end response is not as clear and distorts earlier.
•  You turn your amp’s master volume up to hear the level that
   you are used to hearing.
•  Eventually you will hear 'crackling' 'popping' sounds, often accompanied by:
•  'Swelling' volume levels.
•  Buzzing.

Preamp Tubes:
•  Hissing, 'shooshing'.
•  Sputtering, 'grumbling'.
•  Microphonic squealing (feedback type sound).
•  Loss in signal in one or more modes of the amp (channel, reverb, fx-loop).

[maliciousteve]

aahh I see, Going by the descriptions it sounds like a bad preamp valve as I get loss of signal when using my G Major in the FX loop (works fine in the Laney)

[hunter]

I think that's just normal as the high gain on Engls is so ultra high, it adds overtones in ultrasonic frequencies that kill all sound below 20kHz, so it isn't audible anymore for human beings