Signs when Amp Tubes need to be replaced.

[goodman]

Currently when I trun my tube amp to the point of breakup I tend to get an overdrive sound which is not as warm as it used to be. It sound more metallic. Is this a sign that my tubes need replacing....? What are the signs to look out for when its time to change amp tubes?

[sinasl1]

I had an interesting problem recently- One side of my mesa 2:90 poweramp started swelling up and down in volume, all on it's own. I retubed - problem solved.

[Austinrocks]

from the mesa boogie site

http://mesa.stores.yahoo.net/whattubtotub.html


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).