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Tube Ampp Almarro low level hum

My Almarro 318B amp has recently developed a low level hum that comes and goes. I have swapped out all 4 tubes at one point or another and that does not change it. Once the hum stopped for a few days while I was breaking in a new paid (NOS) of 6C33C tubes. But it keeps coming and going. It gets a bit louder and then softer. If I tap the base of the amp, the hum stops. If I pick up the amp, it stops. If I knock the table where the amp sits, it stops.

I run the amp about 6-8 hours a day. Once a week I foget and leave it on all night.

Any ideas?

Thanks

Dan
mcmanus

Showing 1 response by jessmar

jessmar
9 posts
 
This may not apply to your situation. One of my Threshold SA10e mono amps developed a low level hum that would come and go. Recently the hum would appear more often and became louder. I removed the balanced cable and reconnected. The hum went away and came back within a few seconds. I felt the problem was with this connection. I tightened the two hex screws holding the XLR input in place to 10 inch lbs. and the hum was completely gone with no return visits. I did the same to the other amp and both amps are now dead quiet at zero volumn. I hope this helps someone.
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