Where do I find the VH4 Hum Trimmer?

  • Thread starter Thread starter edgemeister
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edgemeister

edgemeister

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Hey guys, was wondering where the hum trimmer on the VH4 is as I'm getting hum after changing my preamp tubes?

Does it change the sound of your amp if you tweak it too much?


Thanks

John
 
hey bleedback,

It's a small trimpot (the kind you adjust with a screwdriver, not a knob) inside the VH4 that allows you to fine tune the amount of hum coming from the amp.

I ajusted it and still get a slight hum, so I adjusted it to a happy medium where its hardly noticable unless miked up and loud. Both extremes of the pot give off a different tone of hum, and then near the middle of the sweep there is a dead spot where the hum sort of falls considerably...

So the hum I'm getting is more of a base mechanical hum rather than a 'generated' hum sound.

Cheers,

John
 
Hi John, thanks for clearin that one up!
I dont hear no hum at the moment so i'm guessin that I dont need to touch anything?! (If it aint broke......etc.)
I do notice or should i say feel a small vibration on the front panel of the amp sometimes, is it normal, does yours do this?
cheers
warren.
 
edgemeister":be12a said:
hey bleedback,

It's a small trimpot (the kind you adjust with a screwdriver, not a knob) inside the VH4 that allows you to fine tune the amount of hum coming from the amp.

I ajusted it and still get a slight hum, so I adjusted it to a happy medium where its hardly noticable unless miked up and loud. Both extremes of the pot give off a different tone of hum, and then near the middle of the sweep there is a dead spot where the hum sort of falls considerably...

So the hum I'm getting is more of a base mechanical hum rather than a 'generated' hum sound.

Cheers,

John
Click to expand...

Hey John,

ever solved this problem? I have the same issue I guess.
The amp hums,even when the volume is turned down. I also feel it vibrate. I think it's the input power transformer that's resonating (I can feel it do so), and the hum is mechanically transferred to the tubes.

Could it be that re-tightening the transformer to the chassis fixes this? Or is it possible to replace the transformer? I'd love to get this fixed. I'll email peter when he's back from Japan, maybe I can get a new transformer to put in.
 
Does this Hum Trimmer affect the tone of the amp? I just opened up my Herbert to do an inspection and found that Herbie has this trimmer as well.
 
Not its tone, but its hum-balance (heaters). If the amp hums with no volume --> check tubes or rebias at least.
 
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