No sound out of Rebel 20 amp

[munkdo]

Hi, i ordered a rebel 20 some months ago and it quickly stopped working correctly. At first i was very happy with it but soon i started noticing the sound becoming muted after a while of playing. It got so bad I had a high end cable sent back to the store as dysfunctional thinking it was the problem. The problems persisted over the coming months and became worse.

At this point i've tried 3 different cables, connecting the guitar right to the amp with no pedals inbetween and playing until the sound goes completely away, just to be sure. I'm new to tube amplifiers so i coudln't be sure.


What happens is it has noticeably flat tone right from the start and goes away gradually until it just sounds like it coughs. Then if I give it a rest it usually comes back just to die down slowly again. Usually i can get 20 minutes out of it before its completely useless. Sometimes it goes dull and comes back with a surge, in fact i think this was an early problem. Once i noticed this happening and pushed the volume from 2 to almost max and nothing happened. Then i heard a loud thump and it came back on track. I've tried using full watts and no watts to be sure it wasn't that, but i can't be sure. maybe some wiring is wrong?


I've been thinking it may be the tubes, but they look okay through the grille with no coloration as far as i can tell, and the problems started just barely a month after i bought it, maybe before for all i know since this was my first good tube amp.


I've requested to have it sent back to the net store but they have some policies when it comes to normal wear and i'm afraid i'll be stuck with the bill if it is the tubes after all, will check on that tough.


Appreciate any help i can get.

 

[Buckeyedog]

You should be able to send it back. Also, tubes have a 90 day warranty. Tubes can look fine but be bad. Happens all the time. Good luck.

 

[viking22]

First thing to do:always check the tubes!Most of the times,you don't "see" the problem.Look if it's the same when you put the tube knob on 6V6 only or on EL84 only (full left or right).If it's the same,swap the 12AX7's one by one to find if there is a faulty one .(If it only happend with the 6V6's,you replace them etc.)In any case,i would buy a complete set of tubes,you'll need them at some point anyways.Then,i would replace them and try to find the faulty one.Good luck!

 

[munkdo]

@viking:


yes i've checked if its both positions. today it worked well for as long as i played. i dont want to dig around as i dont want to spoil the warrantry / happen to break something. i'm not much of a handy man, but i know this is something you can learn.



i'll call them again, and see how it is. i should be ok.


is this a common problem by the way, and we know its the tubes and not wiring? this is the first time this has happened to me, i have an ac4 that never has gone bad on me and this one ive only had a few months.

thanks



edit: crap they dont cover tubes at all. well i got ripped off by thomann in that case. i'll have to call them again.

 

[viking22]

Yep,it's normal.Unfortunately for us,tube quality has declined..What you describe looks like a tube wearing out.Swapping tubes will not void the warranty.Learn how to do it.It's quite simple.You will find some good vids on YouTube explaining in detail how to do it.Then,if your tubes are more than 3 months old,try to find a good tube retailer (thetubestore,eurotubes,watfordvalves in England etc.).They will help you to buy the right ones etc.

 

[munkdo]

Yep,it's normal.Unfortunately for us,tube quality has declined..What you describe looks like a tube wearing out.Swapping tubes will not void the warranty.Learn how to do it.It's quite simple.You will find some good vids on YouTube explaining in detail how to do it.Then,if your tubes are more than 3 months old,try to find a good tube retailer (thetubestore,eurotubes,watfordvalves in England etc.).They will help you to buy the right ones etc.

ok thx viking

grrr thomann....

you'd think they'd stock amplifiers that wouldn't break just out of the box.

but i will make sure to do that,



by the way do you think its the tubes or the preamp tubes, i've been doing a little reading and it seems that the 'regular' tubes are most often the problem, but how can i be sure?

 

[BadBluesPlayer]

The best way to deal with tubes is to get some spare tubes and have them on hand. Then you can swap out the different tubes - one at a time - with your new tubes to see if each tube is o.k. That's the way to tell which tube is bad. Swap 'em out until the problem is solved. Then you'll know which tube is bad.