Poorly AC30

Si_

Looks like I have a poorly AC30

Was using it tonight and after about 60 minutes of everything rocking and sounding fine I lost 99% of my volume. Tested all the cables and pedals and all were ok so I tried putting it back onto standby and then on again and all was then fixed.. worked again for 20 minutes then the same thing, this happened several times through the night.

I assume it's a failing power valve and I was going to just replace them all, but thought I'd get a 2nd opinion.

ICBM

Probably not a power valve - if just one goes it doesn't drop the volume that drastically. If one shorts badly it could do, but it would probably do other damage or cook itself permanently. Not impossible though, so if you have spares it may be worth replacing the set and see if it cures it.

Is it a model with a valve rectifier? If so replace that if the power valves don't fix it - particularly as the standby switch stresses it on models which have both. If it isn't, suspect a preamp valve.

Si_

Not sure about the rectifier, it's an AC30 CC1 (the 1x12)

ICBM

Si_ said:

Not sure about the rectifier, it's an AC30 CC1 (the 1x12)

Yes, that has a valve rectifier - and is definitely one with the standby switch in the wrong place.

Si_

OK thanks.. I'll start with that and the pre-amps.

Cirrus

 Next time it looses power, try wiggling the fx loop on/bypass switch on the back panel. Might not be that at all, but they're known to go dodgy and cause signal loss like you described.

Si_

I'll try that thanks..

Typically the rectifier tube is one I don't have a spare of

impmann

Cirrus said:

 Next time it looses power, try wiggling the fx loop on/bypass switch on the back panel. Might not be that at all, but they're known to go dodgy and cause signal loss like you described.

I was just going to suggest the same.

ICBM

Si_ said:

I'll try that thanks..

Typically the rectifier tube is one I don't have a spare of

It's probably worth getting a solid-state plug-in replacement as well as a valve, if it does prove to be the rectifier - it will always get you out of trouble and there's never any question of the substitute being faulty as well.

DJH83004

the CC amps are notoriously hard on rectifiers, my advice would be to get a JJ GZ34, in my experience they are the most robust of the modern rectifiers.   

Si_

ICBM said:

Si_ said:

I'll try that thanks..

Typically the rectifier tube is one I don't have a spare of

It's probably worth getting a solid-state plug-in replacement as well as a valve, if it does prove to be the rectifier - it will always get you out of trouble and there's never any question of the substitute being faulty as well.

Any idea where I would get the plug in replacement?

ICBM

Si_ said:

Any idea where I would get the plug in replacement?

http://www.tubeampdoctor.com/product_info.php?category_id=83&products_id=389&mySID=l7IvkKJNDOn-iUgHaJ,An3

Si_

Thanks. 

I might get get one of those as a more reliable replacement rather than the tube option. 

Si_

Yellow Jacket Solid State Rectifier ordered.. thanks. 

Teacherphil

DJH83004 said:

the CC amps are notoriously hard on rectifiers, my advice would be to get a JJ GZ34, in my experience they are the most robust of the modern rectifiers.   

I would second that. The JJ brought my AC30CC1 to life.

Si_

Took a little time to get a replacement but I've now fitted a Yellow Jacket Solid State rectifier replacement, hope that helps to fix the issues. Current rectifier valve looks fine visually but I guess that doesn't mean much. 

If not I'll replace the Pre-amp tubes.