Has anyone figured out the Vox AC4HW hum?

[Phil_S]

I wonder if the group is barking up the wrong tree. Maybe there is some coupling of the unshielded tubes to the speaker. Maybe use tube shields or place a plate between the speaker and the tubes? Just a thought. I have no idea if it's a factor. It might easily be tested with a plate and some tape if there is adequate space. If using a ferrous metal plate, I' suggest you'd want to insulate it with something non-magnetic (felt, cork?) on the speaker side so it doesn't stick to the speaker.

[xtian]

I wonder if the group is barking up the wrong tree. Maybe there is some coupling of the unshielded tubes to the speaker. Maybe use tube shields or place a plate between the speaker and the tubes? Just a thought. I have no idea if it's a factor. It might easily be tested with a plate and some tape if there is adequate space. If using a ferrous metal plate, I' suggest you'd want to insulate it with something non-magnetic (felt, cork?) on the speaker side so it doesn't stick to the speaker.

That would be easy enough to test, by playing an external speaker.

[Phil_S]

D'oh!

[peckjed]

I wonder if the group is barking up the wrong tree. Maybe there is some coupling of the unshielded tubes to the speaker. Maybe use tube shields or place a plate between the speaker and the tubes? Just a thought. I have no idea if it's a factor. It might easily be tested with a plate and some tape if there is adequate space. If using a ferrous metal plate, I' suggest you'd want to insulate it with something non-magnetic (felt, cork?) on the speaker side so it doesn't stick to the speaker.

That would be easy enough to test, by playing an external speaker.

And external cabinet doesn’t change the hum (it appears in the external cab)