Loud static

[Boxnix]

I bought a 5e3 clone from a guy, I don't know much about it, it seems to be built of quality stuff.

It has worked like a hose for about 6 months, today I plugged it in and its making a loud static sound, the guitar is coming through but it seems to be quieter than normal, it does not get much above the static.

I don't have any money to take it in, can anyone give me a starting point? Should I just start replacing tubes?

Edit:

I took a look around after calming down a bit. The smaller xfmr is hanging by one loose bolt. There are some signs of over heating, the large blue sprague caps are loosing their insulation in small spots, a couple others have marks on them.

[loudthud]

Poking around inside an amp can be quite dangerous, even with the power off and the amp unplugged. Study up on this if you are unfamiliar.

Do the volume and tone controls have any affect on the static?

The large blue Sprague caps will sometimes get marks on the side if they are knicked with a hot soldering iron. Don't be concerned about that. When caps go bad you can sometimes see a whitish crusty substance around the rubber seal on the positive end.

The transformer could be at fault, but many are baked in an oven as part of the manufacturing process. Post a picture of it to get more opinions. Find a screw to fasten it down. Tighten up any other screws or nuts that are loose. Verify that there is no loose screw, nut or anything else floating around inside the amp.

As for the static it could be a loose connection somewhere, a bad tube or a loose tube socket. With tubes it's best to try some known good ones from a working amp or try yours in another amp. If you just have new ones, you can try those one at a time. It should be pretty obvious if the problem is a bad one. Finding a loose connection can be a little tricky. Many people like to re-heat connections with a soldering iron and maybe add a bit of fresh solder. Another technique is called chop sticking. An insulated stick like a chop stick is used to wiggle each wire while the amp is on. It's fairly dangerous. Search for advise on how to do it safely.

[Boxnix]

Thanks for the reply. I am aware of the dangers of the caps holding onto the 300V, I don't touch anything until I let the thing sit for a couple days and check it with a meter. I never have rigged up a discharging device, I need to do that. Anyway, thanks for looking out for me, I do appreciate it.

The tone and volume knobs had no effect. Its a very smooth FM type static, no popping at all.

I gotta get some funding to buy tubes. I never hear people talk about matched power tubes with a 5e3, is matching the two 6V6's not a big deal?

[loudthud]

I'm glad you clarified what you ment by the term "static". When I read that term, I usually think of what you hear on an AM radio when lightning is in the area. What you hear on an FM radio between stations is usually refered to as "hiss". Hiss is most likely a tube, possibly a bad resistor, or there is a small probability it's a bad capacitor. Bad solder connections usually cause static, not hiss.

The 5E3 will benefit when matched pairs of 6V6s are used. Be aware that what qualifies as "Matched" can vary widely between vendors. There is no recognized standard.

Edit: One thing that just came to mind. The eyelet board like Fender used can absorb moisture that will cause hiss. The cure can be to just leave the amp on for 24 hours. External heat sources like a hair dryer or oven can work but capacitors don't like heat. Some "plastic" caps can melt. So use caution.

[otto pärt]

Wouldn't Occam's Razor say that the problem is the first preamp tube?

[Chuck H]

The volume and tone controls don't affect the noise so I doubt it's V1. Occam's Razor only works when you narrow down to the simplest answer through recognition of the complications. Which sort of makes it a misnomer since that is basic troubleshooting anyhow.

[Boxnix]

I finally got some time to look at the amp. I bought a new bolt to hold the xfmr in place. There are lots of places where insulation has melted off the wires. I don't know if something may have gotten crossed. I tried to separate them a bit. When I put the tubes back in the amp worked. I'm guessing it will happen again soon but until then I'll just be grateful for small miracles. I was going to replace the tubes but NOS tubes are way more than I thought and I have no idea which one might be bad. Thanks for all the help!