New TH30 has weird hum.

[tony_m_1234]

Just bought a TH30 head yesterday that I am running through an older PPC412. Sounds fantastic. Until I started recording. I discovered there is a fairly quiet 60 cycle hum coming from inside the amp head. It sounds like it's actually emanating from inside the chassis of the head. If you put your ear up to the head you can distinctly hear inside there as long as the amp is on even if nothing is connected and the amp is on standby. When I take it off standby that hum gets amplified and comes through the speaker a bit louder. It's not loud enough that it would be a problem in a live setting. Either it wasn't there or I didn't notice it when I played in the shop and jammed a bit at home. But it becomes noticeable it recordings.

Just wondering if anybody has experienced this and if it's normal or not. I'm afraid if this is just the nature of the amp I will have to return it. If somethings wrong what can I do to fix it?

[a.hun]

It isn't normal - modern Oranges are normally very 'quiet' as far as unwanted hum and hiss is concerned.

If it was just a little acoustic hum that might have just been a slight transformer vibration. Some can do that without it being a problem. (Couple of my amps have that slightly - not a worry.)

But since it is also being amplified with the signal, no not normal. Take it back would be my best advice...


Andy.

[Ronnie Robinson]

If your experienced with good quality valve amps really it should be no different ie is it much louder than another valve amp you have?....then that sounds like a problem.

On Standby there should only be the slighest of hum ....hardly noticable. Yes when you engage 'play' the hum will increase depending on your volume / gain and guitar but this should only be in the background.

If you've just bought it new then I'd take it back. If youve bought it private, second hand I'd change the valves to see what difference that makes.

[tony_m_1234]

Well I've only ever previously owned a DSL100 for quite a long time and I never remember any kind of hum. Other than the normal hum from a guitar and a normal amount of quiet white noise hiss. I definitely don't ever remember a pitched hum actually coming from within the chassis of the head or without anything actually plugged in the front.

I just discovered that flipping the wattage on the front to full or half does nothing, however on the back the 4 tube setting is noticeably louder than the 2 tube setting. Think something could be wrong with the power tubes? Also adjusting the hum balance pot does nothing.

I will admit it is pretty faint and I could probably live with it but it's gnawing at me thinking there could possibly be something wrong with an amp I just dropped 1500 on. I did buy it new so I may bring it to the store.

[Ronnie Robinson]

Could well be a valve ....There should be a 3 month warranty on valves.

[tony_m_1234]

I just remembered I had a Vox AC4 kicking around that I never play. I set it up and it gives off the same hum. I guess it's a pretty normal hum that I just never noticed until now because I have a new amp and I'm being hyper critical. Either that or maybe my speaker cable is weird and has damaged both amps. Is that a thing? I rule out other factors like power in my house etc because the hum is coming from inside the actual amp heads themselves

[Les Paul Lover]

Valve amps do hum a little when switched on. It shouldn't be audible when you're playing though, unless you have a microphonic valve that picks it up and amplifies it.

[tony_m_1234]

It definitely isn't audible when playing. I knew some noise was normal I just found it weird that even with nothing plugged in you can faintly hear some hum coming from the amp head and speakers. I guess it's something I've never ever noticed.