Rivera Help

DLHelfand · Aug 2, 2001

Marshall Help!

I seem to be having a problem with my Rivera Chris Duarte amp. I think that it probably just needs new tubes all around. Here is the problem. It is a two channel amp. I seem to be suffering a large volume drop as I play. I think that it happens in both channels. Lately, I have been hearing a sort of octave effect in the clean channel. Sort of like a BOSS octave pedal with very little effect and mostly dry signal. There also is a high pitched "whine" at times. In addition, the seems to be a lack of gain in the high gain channel. Does this sound like tubes to you? If so, is it just preamp, poweramp or both?

Phil M · Aug 3, 2001

DL, My brother in Rivera

That sounds like preamp tubes to me. The occasional whine and the ghost notes are usually the tell tale signs. BUT...the volume drop sounds kind of weird to me, that might be power tubes but I'm unsure.

Just for shits and giggles, do you have anything plugged into the effects loop? It might have something to do with the adjustable levels. Probably not...

As a last resort, make sure your reverb connections are all good.

Hopefully a pro will be along shortly to give you some ideas, but I'm pretty sure it's time to retube that bad boy.

DLHelfand · Aug 3, 2001

Effectron

I do have a Deltalab Effectron in the loop, but it has been there since I got the amp with no problems...until now. I think that it probably needs all the tubes replaced since, the guy that I got it from was a professional recording and session bass player and he bought the amp to do I session as a guitarist. He told me that after the session it basically sat in his closet for 2 yrs (explaining the mint condition)and then he sent it to me. So I am guessing it still has the stock tubes and the amp is at least 3yrs old. It uses EL34s for power amp and 12AX7a, ECC83, 6681 or 7025 for preamp. Rivera sells matched sets for replacement. Any other recommedations as to where to get replacements?

Phil M · Aug 3, 2001

Lord Valve seems to ring a bell, but there are other places as well. I usually shop around get them from local places.

I'm sure that if you get tubes from Rivera, they'd be great, but you could get the same things from somewhere else for less $$$.

Tim C. · Aug 3, 2001

Try plugging a guitar cable from the effects send into the effects return and play the amp. Make sure you don't have any effects pedals in the mix. If this fixes the problem then you have a dirty or shorted effects jack. This is a common problem with many amps. If yours has been sitting for a few years the jacks could have gotten dirty or dusty.

If that doesn't solve your problem I would suspect power tubes for the volume loss problem, octave and ghost noting.

Try the cable to the effects jacks first before buying tubes.

Good Luck,
Tim C.

DLHelfand · Aug 3, 2001

Thanks

I will try that soon and post back later with the results TimC.

DLHelfand · Aug 9, 2001

Tubes

I called Rivera today and was told that it sounds like a tube problem. He said that under the circumstances (relatively little use since new) that the amp needs new tubes and should not need to be serviced. He told me that I can by matched tubes from Rivera (although he did not push the sale and infact seemed to lead me to other dealers.) Rivera's prive for tubes for my amp is as follows:

5 12AX7WA=$100
4 EL34=$140

plus shipping

Does this seem excessive? I mean they test, burn and match the tubes but isn't that common. These are not NOS.

DLHelfand · Aug 9, 2001

Marshall Help!

Should I rename the thread Marshall help? :wtf Come on guys,:sos I know that you can help. Is this a good price for tubes? Do you know of a better place to purchase them? Any good amp service guys in NYC? :demon

Phil M · Aug 9, 2001

That sounds like a lot to me, shop around.

here are a bunch of sites.

http://www.audionova.nu/Innehall/tubesite_ooc.htm#America

Try Lord Valve too. I haven't been to his site in awhile.

DLHelfand · Aug 9, 2001

ROG

Phil,

I suppose that if you don't play Marshall, Fender or Vox in this place you don't exist...It seems that only Rivera owners are can answer this. I mean it has been viewed quite a few times, yet we are the only two that have posted.

Pickdropper · Aug 10, 2001

Tube Prices

I would get em from somebody else. I bet those are just new production Sovteks. Those could be had for half that price tested from a dealer. Try lord valve or try Uncle Ned at triode electronics. Both have better pricing and will send you tested and screened tubes. Lots of manufacturers will provide tubes as a service to their customers, but they don't usually seem to want to get into the tube supply business. He probably knows they are cheaper elsewhere, that is why he kinda steered you away.

-Dave

DLHelfand · Aug 10, 2001

Thanks guys.

xxmartinxx · Aug 15, 2001

First off, I'd hold off on the power tubes. It's probably just ONE preamp tube creating the whole problem. I had a similar problem where I'd have intermittent volume drop offs and it was one preamp tube causing it. I replaced it and everything was fine.

Those tube prices are pretty high, especially on the preamp tubes. A decent 12AX7 will run you between $9-12. You can get Sovtek 12AX7LPS's (one of the best tubes currently being made) from Musicians Friend.com for like $7, which are normally $13 anywhere else. The problem is they (unlike most places that exclusively sells tubes) do not test them before they sell them. The problem I had came from a DOA tube from them. I'd go with the Sovtek 12AX7LPS's or the new Eletroharmonix 12AX7EH's (if you can find them). Both are great tubes. Preamps are fun to mess with since you can just pop them in and see what happens.

For EL34's I'd go with Svetlana's. They can be had for about $65 for a quad. The problem with the power tubes is once you put them in you need to have the amp biased, which will need to be done by an amp tech. This is usually between $20 and $40.

For more info, check out www.tubestore.com. Great info there.

Rivera Help

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