Help with a dead Rebel 20

[gearaddict]

Hi - first post, go easy

I have had a Rebel 20 for about 5 months and I love the sounds but unfortunately a couple of days ago it started intermittently cutting out and then on Saturday night it died on me completely in the middle of a gig (Argh!).

There is no sound out of the amp at all - complete silence. Not even a hiss. The power light is on and all 4 power tubes are merrily glowing away. Both slo-blo and fast-blo fuses are ok. I tried running a pedal into the fx return of the amp to see if the power stage was working - nothing.

If it was a blown power tube (say an EL84) would I be able to get sound back by turning the tube mix control to the other set of tubes (so, the 6V6s)?

Just trying to eliminate the obvious before I send it off for a warranty repair.

 

[viking22]

If it was a blown power tube (say an EL84) would I be able to get sound back by turning the tube mix control to the other set of tubes (so, the 6V6s)?

Yep.It's supposed to work that way;if one EL84 was dead,you should still be able to play with the 6V6's only.Sorry for you

 

[Len Rabinowitz]

I don't suppose it is something obvious like a bad guitar cable or speaker cable- sound not getting in or out? Maybe it isn't the amp?

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[gearaddict]

I don't suppose it is something obvious like a bad guitar cable or speaker cable- sound not getting in or out? Maybe it isn't the amp?

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Unfortunately not...swapped the Egnater with my backup amp and all was well again...everything else seems to be working ok.

It's kind of annoying because I bought the Rebel as a replacement for my Marshall DSL-50 which had become unreliable...at first I couldn't believe I had another amp cutting out on me...it wasn't until the amp died completely that I was sure it was the Egnater.

Before it happened I had actually been considering trading up to the Renegade head...I could do with the extra volume. But now I'm a bit uncertain about the reliability of these amps...

 

[mboogman]

Check all the Pre-amp tubes. Could be any one of them, especially the effects loop return stage (if there is one?) or phase inverter. Either one of these going out could explain your issues.

 

[Steedee]

Yeah definitely check out the preamp tubes.
Was there any hiss, pop or smoke before it went out? Anything?
Hope it's not something serious.
Good luck on quick resolution.

 

[gearaddict]

Yeah definitely check out the preamp tubes.
Was there any hiss, pop or smoke before it went out? Anything?
Hope it's not something serious.
Good luck on quick resolution.

I don't think it can be the pre-amp tubes - I tried running my HT-Dual pedal straight into the fx return of the amp - nothing.

There wasn't any pop or smoke that I noticed myself but the drummer said he smelt a burning smell.

 

[BadBluesPlayer]

Sounds like its probably a preamp tube. You will want to have a spare or two on hand so you can swap them out when something like this happens. When it sounds bad, its usually a preamp tube.

 

[gearaddict]

Sounds like its probably a preamp tube. You will want to have a spare or two on hand so you can swap them out when something like this happens. When it sounds bad, its usually a preamp tube.

If it was a pre-amp tube would I not be able to get a sound by running my HT-Dual into the FX return? Or would a dead pre-amp valve stop the FX loop from working? Someone above mentioned a pre-amp tube on the fx loop return stage...

...Actually that would make some kind of sense. Just before the amp died completely it was intermitently cutting out and it seemed to happen most when I hit my solo boost, which is a clean boost in the fx loop - which would be driving the FX return harder...dunno if that makes sense...

 

[mboogman]

Sounds like its probably a preamp tube. You will want to have a spare or two on hand so you can swap them out when something like this happens. When it sounds bad, its usually a preamp tube.

If it was a pre-amp tube would I not be able to get a sound by running my HT-Dual into the FX return? Or would a dead pre-amp valve stop the FX loop from working? Someone above mentioned a pre-amp tube on the fx loop return stage...

...Actually that would make some kind of sense. Just before the amp died completely it was intermitently cutting out and it seemed to happen most when I hit my solo boost, which is a clean boost in the fx loop - which would be driving the FX return harder...dunno if that makes sense...

The signal still needs to run through the phase inverter tube before it gets to the power section as far as I know. If the PI / driver tube went out, you wouldn't get any sound at all, just like if a power tube went out, IIRC.

 

[gearaddict]

The signal still needs to run through the phase inverter tube before it gets to the power section as far as I know. If the PI / driver tube went out, you wouldn't get any sound at all, just like if a power tube went out, IIRC.

Sorry for the stupid question but is the PI tube a standard pre-amp tube? The Rebel 20 has 3 12AX7 tubes in there and it just so happens I have some 12AX7 tubes from my old Marshall I could swap them with.

I presume I just unscrew the little metal covers and swap the valves over, yes? The pre-amp ones don't require any biasing or anything like that do they?

I've not fiddled with the insides of a valve amp before...I know there are lethal voltages in there and that they can hang around for a while even when switched off...what should I do to avoid actually dying?

 

[Ian Egnater]

Back to the original post. Did you check the fuses with a meter, or just visually? I only ask, because fuses can be blown and look completely fine visually. Just trying to save you the trouble of taking it for warranty repair if it's something easy like a bad tube blowing your fuse. It won't be the "Mains" fuse by the power cable, so just check the other fuses by the tubes.

 

[gearaddict]

Back to the original post. Did you check the fuses with a meter, or just visually? I only ask, because fuses can be blown and look completely fine visually. Just trying to save you the trouble of taking it for warranty repair if it's something easy like a bad tube blowing your fuse. It won't be the "Mains" fuse by the power cable, so just check the other fuses by the tubes.

Hi - yes I did check them with a meter...seem ok.

 

[mboogman]

The signal still needs to run through the phase inverter tube before it gets to the power section as far as I know. If the PI / driver tube went out, you wouldn't get any sound at all, just like if a power tube went out, IIRC.

Sorry for the stupid question but is the PI tube a standard pre-amp tube? The Rebel 20 has 3 12AX7 tubes in there and it just so happens I have some 12AX7 tubes from my old Marshall I could swap them with.

I presume I just unscrew the little metal covers and swap the valves over, yes? The pre-amp ones don't require any biasing or anything like that do they?

I've not fiddled with the insides of a valve amp before...I know there are lethal voltages in there and that they can hang around for a while even when switched off...what should I do to avoid actually dying?

Preamp tubes are a simple plug and play deal, as long as they're the same basic type (12ax7, 12at7, 5751, 7025, etc). The PI tube is a standard preamp tube. As long as you don't open up the entire chassis, you'll be safe from lethal voltages.

 

[Ian Egnater]

Since the fuses checked fine on the meter, really your last step before doing warranty work is to try swapping the phase inverter tube. Don't bother replacing all of the preamp tubes. Just go to:

http://egnateramps.com/FAQ.html

Download the pdf of the Rebel 20 tube chart at the bottom of the page and look for the V3 tube, if you are unsure of which tube is the phase inverter. There really is no danger in doing this, aside from the tube being warm. Just do it with the amp off. Don't go buy a new tube in hopes of it fixing the problem though. Contact nate@egnateramps.com and he can help you out with any further trouble shooting on the amp. Hopefully that info helps a little bit.

 

[gearaddict]

Since the fuses checked fine on the meter, really your last step before doing warranty work is to try swapping the phase inverter tube. Don't bother replacing all of the preamp tubes. Just go to:

http://egnateramps.com/FAQ.html

Download the pdf of the Rebel 20 tube chart at the bottom of the page and look for the V3 tube, if you are unsure of which tube is the phase inverter. There really is no danger in doing this, aside from the tube being warm. Just do it with the amp off. Don't go buy a new tube in hopes of it fixing the problem though. Contact nate@egnateramps.com and he can help you out with any further trouble shooting on the amp. Hopefully that info helps a little bit.

Hi Ian - thanks for your help. Before I read your post I actually went ahead and replaced all 3 pre-amp tubes (I had some left over from when I revalved my Marshall). In fact I tried the PI one first (I guessed where it would be and having looked at the diagram I got it right!) but this had no effect, so I tried all 3 - still no luck. I just packed it up ready for return to the shop.

 

[Steedee]

Since the fuses checked fine on the meter, really your last step before doing warranty work is to try swapping the phase inverter tube. Don't bother replacing all of the preamp tubes. Just go to:

http://egnateramps.com/FAQ.html

Download the pdf of the Rebel 20 tube chart at the bottom of the page and look for the V3 tube, if you are unsure of which tube is the phase inverter. There really is no danger in doing this, aside from the tube being warm. Just do it with the amp off. Don't go buy a new tube in hopes of it fixing the problem though. Contact nate@egnateramps.com and he can help you out with any further trouble shooting on the amp. Hopefully that info helps a little bit.

Hi Ian - thanks for your help. Before I read your post I actually went ahead and replaced all 3 pre-amp tubes (I had some left over from when I revalved my Marshall). In fact I tried the PI one first (I guessed where it would be and having looked at the diagram I got it right!) but this had no effect, so I tried all 3 - still no luck. I just packed it up ready for return to the shop.

Dang that sucks.... Burnt smell is never good...
Hopefully a speedy return is in order!

 

[Daavvt]

Since the fuses checked fine on the meter, really your last step before doing warranty work is to try swapping the phase inverter tube. Don't bother replacing all of the preamp tubes. Just go to:

http://egnateramps.com/FAQ.html

Download the pdf of the Rebel 20 tube chart at the bottom of the page and look for the V3 tube, if you are unsure of which tube is the phase inverter. There really is no danger in doing this, aside from the tube being warm. Just do it with the amp off. Don't go buy a new tube in hopes of it fixing the problem though. Contact nate@egnateramps.com and he can help you out with any further trouble shooting on the amp. Hopefully that info helps a little bit.

Ian, the "authorized repair centers" link from the FAQ does not seem to work, just FYI.

Dave

 

[Ian Egnater]

Since the fuses checked fine on the meter, really your last step before doing warranty work is to try swapping the phase inverter tube. Don't bother replacing all of the preamp tubes. Just go to:

http://egnateramps.com/FAQ.html

Download the pdf of the Rebel 20 tube chart at the bottom of the page and look for the V3 tube, if you are unsure of which tube is the phase inverter. There really is no danger in doing this, aside from the tube being warm. Just do it with the amp off. Don't go buy a new tube in hopes of it fixing the problem though. Contact nate@egnateramps.com and he can help you out with any further trouble shooting on the amp. Hopefully that info helps a little bit.

Ian, the "authorized repair centers" link from the FAQ does not seem to work, just FYI.

Dave

Thanks for the heads up, I'll point that out to our web guy.

 

[gearaddict]

The Story So Far:

I sent the amp back to GuitarGuitar in Newcastle (UK) and they checked for obvious faults (tubes etc) but could not fix it. So they told me they would send it back to Egnater US for repair and it would be about 2 weeks before I got it back. That was about 2 and a half weeks ago and GuitarGuitar are being a bit useless about telling me what is going on. I was wondering if anyone on here might have an idea who I could contact at Egnater to find out if they have fixed my amp or any information about what is going on?

Thanks!