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OR15 issues
Posted: Mon Feb 05, 2018 12:58 pm
by rock4blaqkhearts
I was playing my OR15 yesterday and the volume just dropped suddenly.
It was very noticable. It sounded like it was muffled. I tried different guitars and I'm using new cables so it's probably the amp. I don't play that loud either. This is just playing at modest volumes at home. I turned off the amp and waited about 10 minutes and tried again and the amp was fine. I'm assuming it can't be the power tubes because then it wouldn't produce any sound. Correct? As far as I know, it's a solid state rectifier. So is it the preamp tube? If so why is it working now?
Any suggestions and fixes are appreciated.
Thanks.
Re: OR15 issues
Posted: Mon Feb 05, 2018 1:34 pm
by Les Paul Lover
Valves can die in a variety of ways.... and being an intermittent pain before to totally go is one of them.
I'd still suspect the power valves, but it could also be a preamp valve, or a solder point / component not liking the heat and failing.
New cables can have faults too. Until you know what is the issue and rectify it, it could be a number of things.
Re: OR15 issues
Posted: Mon Feb 05, 2018 4:22 pm
by PBA
Ant is correct.
It could be anything. You don't say how old the amp is or how long you've had it. Power amp valves are always going to be a suspect, followed by pre-amp valves. You do mention new cables. Just because they are new doesn't mean they are free from fault so it might be worth reverting back to older cables.
If you're using it only at home you might have the luxury of just leaving it and seeing if it happens again. Remember though that it will still fail at the most inappropriate time!
It's always a good idea to have some tried and tested spare valves on hand. OR15 is cathode biased so you should be able to swap valves without using a tech to re-bias.
Re: OR15 issues
Posted: Tue Feb 06, 2018 3:36 am
by rock4blaqkhearts
PBA wrote: ↑Mon Feb 05, 2018 4:22 pm
Ant is correct.
It could be anything. You don't say how old the amp is or how long you've had it. Power amp valves are always going to be a suspect, followed by pre-amp valves. You do mention new cables. Just because they are new doesn't mean they are free from fault so it might be worth reverting back to older cables.
If you're using it only at home you might have the luxury of just leaving it and seeing if it happens again. Remember though that it will still fail at the most inappropriate time!
It's always a good idea to have some tried and tested spare valves on hand. OR15 is cathode biased so you should be able to swap valves without using a tech to re-bias.
It's a three year old amp. I bought it used about six months ago. The previous owner changed the tubes six months prior to that. So I'd say the tubes are about a year old. Now I don't know whether he changed just the power tubes or fully retubed. Either way, I'm thinking about fully retubing anyway.
But I didn't think it needed it so soon since I mostly play at bedroom levels.
Re: OR15 issues
Posted: Tue Feb 06, 2018 10:48 am
by Les Paul Lover
Think of valves just as light bulbs.
They can go any time.
They also are the only "consumable" within the amp. As they deteriorate, it's good practice to inspect them as soon as something goes wrong. 95% of the time, they are the issue.
Re: OR15 issues
Posted: Tue Feb 20, 2018 11:17 pm
by tolm
Sounds like the power tubes: I had a set of Gold Lion EL84s do that in my old Jackson Ampworks Newcastle 30 ... would sound great, then a sudden drop in volume and complete loss of “girth”. Power off ... let everything cool ... back on and all good for a couple of minutes then same again. And repeat.
I just completely retubed a second hand AD30 I bought and the difference is night and day: I’m talking from “oh no, I made a terrible mistake” to “holy cow, this is the greatest amp I’ve ever played”.
Valves, man. It’s ALWAYS the valves. At least, most of the time ...
