Problem with Randall RG50TC

[nmorales30]

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[crane]

What kind of guitar do you use ?

 

[nmorales30]

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[crane]

Ok, not a pickeups pb it seems if it happens with any guitar.
Could be a problem with your AC. Try plug your amp in another room or house.
Could also be a tube problem. A preamp tube is probably microphonic.
You can try to gently tap on each tube with a pencil or a nail while on the clean and overdrive channel.
If one of the tube makes a big noise you could replace it and see if it's better.

 

[stokes]

This is common in amps with a "clean" and "high gain" channels.The overdrive channel develops a lot more gain,or amplification,if you will.All tubes have some degree of microphonics and noise,when you use the overdrive or high gain channel these noises are amplified more than in the clean channel,some tube suppliers sell tubes that are specially selected for low noise or microphonics to be used in high gain amps for just this reason.In some cases components,like a plate load resistor,become noisy,in that case tube changes wont help.