what is wrong with my amp?

[cstockdale]

Fender Hotrod Deluxe, limited edition tweed.

It is crackling badly. Kind of like when your guitar patch cord isn't quiite making contact sort of sound, but it isn't the cord (I have tried 8 different ones), it isn't the guitar (I have tried 3), even with nothing plugged in and the volume on the amp all the way off, it makes this snap-crackle sound. All tubes light up when powered on....

any ideas?

 

[donkeystyle]

my rivera knucklehead does the same thing sometimes........i keep meaning to get it checked out.

 

[Dakota]

It could be a dirty control. Try turning each control to see if a certain one increases or decreases the crackle. Radioshack used to sell a spray, "Tuner Cleaner" i think, that will clean controls sometimes.

Or it could also be a worn cap or diode or something. Does it make the sound when the amp is cold, or only when it's warmed up for some time?

 

[donkeystyle]

i duno about the other guy, but mine can do it from the time you turn it on till the time you turn it off, but it's not constant and it doesn't do it everytime i use it.....well i dont think.......i'll have to start paying more attention.

hmmm worn cap or diode huh? is that expensive or hard to fix? i guess finding which one is the worn one is probably the hardest part huh?

 

[Dakota]

Yea ds, finding the bad one is the hard part, especially if it hasn't failed completely and is only weak. Hard failures are easier to find. Once you find it, it shouldn't be more than $5. Labor costs can eisily be 10X that.

 

[Henri Devill]

Sometimes it can be dirty tube sockets...belive it or not..had it happen to me with a amp it took forever to find the prob




Don

 

[donkeystyle]

it would probably just consist of testing until i find the bad one, then getting a new one, unsoldering the old one, and soldering the new one on, right?

my dad's good with electronics stuff, and i work with a guy that used to build some kind of electronics stuff with circuit boards and crap......one of them should be able to do that easy.

and sorry for highjacking the thread, but i think that this is the kind of info the first guy was looking for too

 

[donkeystyle]

Sometimes it can be dirty tube sockets...belive it or not..had it happen to me with a amp it took forever to find the prob
Don

how do you clean them? or do you just replace them?

 

[Henri Devill]

I don't know the Tech did it..It was cleaning though and not replaceing...




Don

 

[Dakota]

Again, "Tuner Cleaner" spray from radio shack! Spray some in the socket and work the tube in and out a few times. Make sure the power is off and all the caps are discharged first!

 

[cstockdale]

Thanks for the info, I will do some poking around and see if I can narrow it down.

 

[Outlaws]

I have a couple pops that randomly occur while my ProJunior is cranked. Supposedly this is a common problem with those amps. Maybe the whole line too. I don't know. But from what I gather, its the tubes. I just ordered some JJ EL84 to replace the Sovtec that came with it. I'll let you know if that fixes it after they arrive.

Then again, I don't know how bad yours is. Mine is just something that happens about every 5 - 10 seconds when fully cranked or there abouts.

 

[cstockdale]

I think I have it: a power amp tube was not sitting all the way in the socket . There are two in the amp, and until you take the back plate off, you can't really see one of them all that well, so I couldn't tell it was loose. I will know soon enough if that did it, but I just got 15 minutes with no crackle.

 

[Light]

Do not go poking around inside your amp unless you know what you are doing.

High voltage capacitors hold on to enough voltage to KILL you. Unless you are an electronics expert, you would be stupid to try and fix your own amp, not because you might damage the amp (though you might), but because you might damage yourself.

Just don't do it.

You can clean the pots, if you are careful not to touch anything, and they are unsealed pots. Don't mess with any of the rest of it. This is your life we are talking about.

And no, I do not do amp repair, not even for myself.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[Light]

I think I have it: a power amp tube was not sitting all the way in the socket . There are two in the amp, and until you take the back plate off, you can't really see one of them all that well, so I couldn't tell it was loose. I will know soon enough if that did it, but I just got 15 minutes with no crackle.

You didn't touch the glass, I hope? If you did, you need to clean it, and let it dry completely, or your tube will develop a hot spot, and you will shorten the life of the tube significantly.


Light

"Cowards can never be moral."
M.K. Gandhi

 

[cstockdale]

I did not touch the tube with my fingers, I was wearing a glove... just call me Michael Jackson, except I don't like kids the way he does.

 

[Major Tom]

You didn't touch the glass, I hope? If you did, you need to clean it, and let it dry completely, or your tube will develop a hot spot, and you will shorten the life of the tube significantly.

You are thinking of quartz halogen bulbs. No problem touching tubes with fingers, at least not in the 30 or so years I have been using tube amps. I also mark mine with a sharpie right on the glass, so when I pull them out I know which position they were in. Also put some silicone on one by accident - which gave me the idea to try to put some beads of it on them in an attempt to reduce tube rattle in combo amps...haven't gotten around to it yet.

 

[Light]

That is what all of my electronics guru guys I know told me, and as a lighting designer (that is my other job), I can sure believe it. I have seen lamps which have been touched with bare hands, and they look kind of funny. They get big bulges, and if you were a finger print expert you could find the idiot stagehand who didn't listen to your instructions when installing the $700 lamp in your $9000 moving light. And god save the guy who touches a projector lamp (at something like $2500 a piece).


Light

"Cowards can never be moral."
M.K. Gandhi

 

[Dakota]

Damn! Projector lamps gotta reach nuclear temps! What's a tube amp gonna reach? 300-400 farrenheit? maybe 450? But still, those tubes ain't cheap, so I ain't gonna be leavin no finger oils on them anytime soon.

 

[Toker41]

I thought tubes get to like 1300 F.

The problem with the amp is that it is not a Boogie.