# Diagnosing amp problem



## JHarasym (Mar 27, 2007)

My Trinity Lightning 15 (2xEL-84 power section, 3 x 12AX7 preamp, tube rectifier) suddenly starting humming, increasingly loudly. I switched it off, and when I turned it back on the hum had stopped, but the amp sounds much darker. What would be the recommended DIY steps to try before taking it to a tech?


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## Lemmy Hangslong (May 11, 2006)

When it was humming did you look at the tubes?

A hum that builds could be a power amp tube issue where you would usually see one of the tubes burning cherry red. 

At minimum have the Bias current checked.

It's also worthy to note that this could be a nusance issue that rarely occurs.

Having said that it's always best to look into any apparent problem before any further damage could occur.

Cheers
Craig


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