Amp Crackling and Popping

Could be many things, but that happens quite often when tube is about to depart for the big tube store in the sky.

 

did you try cleaning tube pins with deoxit or similar contact cleaner?

how old is amp?

 

I second this-- if you unplugged and reseated the tubes and it got worse, it sounds like dirty tube pins. DeOxIt makes a kit to clean them well. I had a problem in an old Ric with this and I couldn't get them clean. I eventually put in a new socket.

 

Let us know if you get it sorted

 

Does it pop and crackle with nothing plugged in to the input?
12ax7's are inexpensive. I'd order one and test all three positions. If you don't have deoxit, that should also be ordered. These are both items that you'll end up using in the future, so it is money well spent, imo.

 

For sh!ts and giggles, plug on OD into the return of the fx loop. This will bypass the pre-amp. If the popping goes away, then you'll know the problem is definitely in the pre-amp section.

 

filter caps is next on the list of suspects. which means tech, unless you are good with soldering.

 

I would order a full set of tubes first thing (It's always a good idea to have spares, no matter what). Replace the preamp tubes one at a time first, then do both power tubes (although you may need to bias the power tubes, if the crackling stops when you replace them, you'll know that was the problem before you take it to a tech to get it biased)

You mentioned contact cleaner... What kind did you use? Also, how did you use it? My suggestion here is to use a good contact cleaner, and push the tubes in and out a couple of times to make sure you kinda scrub the gunk off.

As for crackling from components, if it's more than tubes, it's obviously beyond what you are comfortable messing with. But, I had some carbon comp resistors that needed replacing and they were crackling.

 

Another possibility is that Rivera amps use a similar channel switching design as the Fender Concert II, a Rivera-era amp at Fender.

These LDRs--led light dependent resistors--the modern "tremolo bug".
These can fail and make a crackling noise.

 

Check the input jacks and the resistors and connections there before picking up new tubes. Could be something broken.