Bare Knuckle Pickups Forum
Forum Ringside => Tech => Topic started by: fletchismint on April 14, 2008, 06:15:30 PM
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Hi guys, I've asked this in a few places but either been ignored or drawn a blank.
The amp is a Rivera designed Deluxe Reverb 2 from 1984. It used to have a wonderful creamy distortion until a few years ago when I switched it on and got a sound not unlike a wasp in a tin can. I've taken to amp repair places and they replaced the valves and looked at it but couldn't improve the sound significantly.
I want to sell the amp and it's probably worth quite a decent amount of money if fully working, but I don't want to send it to another repairer as I've already taken it to 2 so far and don't want to spend any more money on it than I have to.
I would be grateful for any ideas or suggestions.
Thanks in advance.
Fletch
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Some of the amp techs here will chime in soon enough. I don't know Jack Sh!t about this subject.
Have you contacted Rivera on this matter?
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Some of the amp techs here will chime in soon enough. I don't know Jack Sh!t about this subject.
Have you contacted Rivera on this matter?
Do you think he would help me out on an amp he didn't manufacture?
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The worst thing that could happen is that he says no.
I think that an amp designer thinks of his designs as his babies. If I designed it, I would help ya.
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A similar thing happened to me once with a f**ked output transformer - have you had that checked?
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The worst thing that could happen is that he says no.
I think that an amp designer thinks of his designs as his babies. If I designed it, I would help ya.
Hmmm. Can't seem to find his email, or even an email for Rivera Amplification on his site.
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A similar thing happened to me once with a f**ked output transformer - have you had that checked?
I'm not sure what the amp guys I took it to actually checked. They didn't give me a breakdown of what they did :? .
The clean channel is absolutely fine from what I can hear. Surely the output transformer would affect this too?
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We had a DRII in a couple of weeks ago which the owner wanted revalving and servicing. I assume this wasn't yours as this one sounded fine.
If the problem is only on the distortion channel it is very unlikely to a problem with the output stage.
Without looking at the amp my guess would be that there is either a problem with a component in the preamp (unlikely but should be easy for a competent tech to find) or a problem with the channel switching. The switching on the DRII uses optocouplers which are not the most reliable devices. Also the way the switching is implemented means that the switching elements have a filtering effect on the guitar sound. Interestingly using the footswitch changes the distortion channel sound when compared with using the switches on the front of the amp. Unfortunately many "techs" don't really understand how the switching works on a DRII.
I am amazed that amp techs can get away with not telling customers what they have done to an amp (although I often think that this is due to the fact many of them don't know what they are really doing), and can charge for not fixing something. If we can't fix it at an economic cost we don't charge. We also always return any parts we have removed from an amp.
Anyhow if you don't want to throw more money at a repair shop you could try changing the optocouplers in the amp (use two Vactrol VTL5C1s), although without looking at the amp I can't be 100% sure that this will work. Also you must ensure the polarity is correct.
If the optcouplers are not the problem changing them won't cure the problem but won't do any harm, however if you botch it and make the situation worse you will have to take it to an amp repairer who may take a dim view of your attempts to repair it........
Anyhow there is some useful info on Rivera era amps on this site:
http://www.geocities.com/twoseriesfenders/index.html
Good luck and let us know how you get on.
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We had a DRII in a couple of weeks ago which the owner wanted revalving and servicing. I assume this wasn't yours as this one sounded fine.
If the problem is only on the distortion channel it is very unlikely to a problem with the output stage.
Without looking at the amp my guess would be that there is either a problem with a component in the preamp (unlikely but should be easy for a competent tech to find) or a problem with the channel switching. The switching on the DRII uses optocouplers which are not the most reliable devices. Also the way the switching is implemented means that the switching elements have a filtering effect on the guitar sound. Interestingly using the footswitch changes the distortion channel sound when compared with using the switches on the front of the amp. Unfortunately many "techs" don't really understand how the switching works on a DRII.
I am amazed that amp techs can get away with not telling customers what they have done to an amp (although I often think that this is due to the fact many of them don't know what they are really doing), and can charge for not fixing something. If we can't fix it at an economic cost we don't charge. We also always return any parts we have removed from an amp.
Anyhow if you don't want to throw more money at a repair shop you could try changing the optocouplers in the amp (use two Vactrol VTL5C1s), although without looking at the amp I can't be 100% sure that this will work. Also you must ensure the polarity is correct.
If the optcouplers are not the problem changing them won't cure the problem but won't do any harm, however if you botch it and make the situation worse you will have to take it to an amp repairer who may take a dim view of your attempts to repair it........
Anyhow there is some useful info on Rivera era amps on this site:
http://www.geocities.com/twoseriesfenders/index.html
Good luck and let us know how you get on.
Cheers for your help.
I'm in London myself. Where are you based? I don't think I'd be able to do any work on it myself and I still want it fixed as it was a beautiful sounding amp.
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Check my profile for details.
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i agree with jpfamps - it cannot be an output stage if that fault is only on a distortion channel unless you haven't noticed it on the clean one as i might be less noticable there. if it's really only distortion channel issue two of the optocouplers might be the case.