Basic Tube Amp Questions

Michael Miller · Post by **Michael Miller** » 16 Apr 2003 7:57 am

My first tube amp-a brand new Fender Pro Junior to run my lap steels through. Has a noise (with no instrument plugged in) that is constant (not real loud but noticable). After plugging the guitar in, it does not change. It is becomes not noticable when I play, so a couple of basic questions please: Is it the nature of tube amps to be noisier than solid state? Is it reasonable to expect a fender tube amp to be dead quiet? Is it possibly an AC electricity conditioning problem or just crappy tubes? I hate to spend money on a brand new amp so I need some advice? Should I live with it? Send it back? Try the warranty? Thanks in advance![This message was edited by Michael Miller on 16 April 2003 at 09:38 AM.][This message was edited by Michael Miller on 16 April 2003 at 10:43 AM.]

Gino Iorfida · Post by **Gino Iorfida** » 16 Apr 2003 9:59 am

What kind of noise is it? is it a hissing noise? a humming noise? a buzzing? Does it change in relation to any/all of the controls?

I've built and repaired tube amps that are dead quiet even with all controls maxed, so my guess is something isn't right here, but it ould be anything (for example, reverb tanks do pick up noise from time to time etc), it could be something as simple as a bad tube (shipping woes), or something else... more info please

Michael Miller · Post by **Michael Miller** » 16 Apr 2003 11:04 am

Thanks Gino. I will try it again tonight to getter a better description of the noise. I know that it does not change in relation to either the tone or volume controls (that's all it has). I will post again tomorrow.

Michael Miller · Post by **Michael Miller** » 17 Apr 2003 3:28 am

Definately a constant hum. No weird appliances, flourescent lights, computers, etc. running. If I was playing with non-amplified acoustic instruments, it would be distracting. Guess I need to send it back. Should not have to spend money on something brand new IMO. Over on Fender Forum there is a lot of discussion of hum in this amp. Many ideas but no real fixes offered. So I guess it is a design problem.

Dennis Detweiler · Post by **Dennis Detweiler** » 17 Apr 2003 4:29 am

My first guess is filter capacitors.???

Michael Miller · Post by **Michael Miller** » 17 Apr 2003 5:05 am

It has plenty of volume though. I heard low ouput was an indicator of bad filter cap.

Gino Iorfida · Post by **Gino Iorfida** » 17 Apr 2003 6:25 am

YOu can have bad filter caps and still have full volume, , in fact a lot of times they wont even hum, but you'll notice a 'ghost note' when you overdrive the amp. IF it's a brand new amp, definitely send it back...