Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on April 21, 2024, 01:52:38 pm

Title: noisy pt
Post by: joesatch on April 21, 2024, 01:52:38 pm
does a PT with a physical hum cause audio hum through the speakers?
Title: Re: noisy pt
Post by: Glenn on April 21, 2024, 02:05:09 pm
On my Rocket the big PT with dual secondaries hums a bit but doesn’t come through the speaker
But this is by no means a set in stone thing. It depends how big a hum I guess.
Sorry, good luck
Title: Re: noisy pt
Post by: acheld on April 21, 2024, 03:37:14 pm
It should not cause a hum in the speaker.   

Transformer hum is due to magnetic forces acting on both the core (ferrous) material and on the windings themselves.  Sometimes you can fix this by tightening the bolts on the core, but not always.

Think of the step down transformers on your street which hum.  Some more than others.

The PT is already passing AC to your rectifier and filter network, no different than usual.
Title: Re: noisy pt
Post by: joesatch on April 21, 2024, 03:48:39 pm
imma swap it out anyway. can't sleep at night
Title: Re: noisy pt
Post by: acheld on April 21, 2024, 06:28:53 pm
Well, heck yeah!   No value in a noisy PT keeping you up at night . . .  Life's too short.  :icon_biggrin:
Title: Re: noisy pt
Post by: uki on April 21, 2024, 08:37:18 pm
Put some pressure on that bolt !!