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So I bought a fender pro jr a couple of weeks ago and it's been great however I have been struggling a little bit to tame the crackle and hum.

For some reason if I change v1 from the stock valve I get a really bad buzz. Even if I swap the valve that's in v2 with the v1 valve I get hum. I even just bought a brand new valve that I paid to be premium tested for low noise/microphonics and that also buzzes when in v1. Is this stock valve magic?

Although the stock valve stops the hum it instead produces a crackle. I think it may be a problem to do with the valve socket as for some reason every valve I put in is loose apart from this stock one?

Anyone else have any ideas or should I just take the amp to a tech?

I never change valves myself.

They cost too much to do trial and error, and usually don't have a normal return policy. Let a tech do it and you'll only get charged for the parts that actually end up in your amp.

sounds odd. preamp tubes are definitely something you can change yourself without any fuss though, so i wouldn't worry about that.

if the amp is new or under warranty i'd just return the bloody thing. you're gonna be paying for a tech to diagnose and resolve the issue which is going to make it expensive this early on.

maybe you're not seating the tubes properly? additionally, how are the preamp tubes linked to channels? if it's one channel, you'll need to take the buggy tube completely out. if i'm clutching at straws i'd say it could be a cold bias, which may explain the ever present hum, or something like that, but i have no idea why it would interfere with how the preamp tubes respond.

I got one of these as my first tube amp and I was really psyched about it at the time, until I took it into a shop to demo overdrive pedals and the tech there stopped me immediately because of the background noise coming from the amp. After he tested all the tubes he found one that was getting way hotter than the others. After troubleshooting the tubes and amp itself for a while he told me that I'd be better off taking it back to the place I got it and exchanging it. I just beat the buzzer on the warranty because it was used too, so I'm really glad I took it in. He did say that the smaller Fender tube amps (Pro Jr. and Blues Jr. specifically) were prone to excess noise, but that's the most he could tell me.

You could try the twisted heater wire fix if that model doesn't have twisted heater wires, or some of the tricks in >this< article. Certainly get a lot of articles on Googling fender pro junior heater wire twist fix

Already done the heater twist fix. Ahh, might just shift this amp and pick up a ZT again as that was ridiculously portable.

Do you have other tube amps where you're playing? If so, do they make the crackling noise too? Crackling to me seems more like AC line noise. Those amps (really all of that series of Fender tube amps---Pro, Blues, Hot Rod, etc.) are indeed fairly noisy, and in my experience, prone to pick up that kind of thing more than usual.

Yeah the Fender is just my small valve amp, no issues with my Rivera. Should say the crackle goes away if I wiggle the valve in the socket?

Hah, well then. As others said, sounds time to exchange it if you can

Gabriel wrote:Already done the heater twist fix. Ahh, might just shift this amp and pick up a ZT again as that was ridiculously portable.

Although the Google search I mentioned references the twist there are other things about hum and noise that come up as well, did you take a look?

I think something more significant is wrong with the amp. Was using it cranked in rehearsal today to get it to break up and it died on me. Taking it to an amp tech this week to find out the prognosis.

check for dirty/loose tube sockets.

Check if you have any m0j0 leaking from your reverb handle.

Sloan wrote:check for dirty/loose tube sockets.

I think this is the problem, the V1 socket is really loose.