Rivera & el-34 & el-84's

Hi,

Just have a quick question about tubes:

There are EL-84 Electro-Harmonic power tubes in there now. On the back of these tubes it says "Made in Russia" with a "00 01" stamped below it. What does this mean? I'm not to sure of the prior history of this amp (bought it off ebay). So, are these non-stock tubes? Do you think it was rebiased? I noticed that the Rivera web page says that it comes stock with EL-34's. I assume these tubes are different, but can I run with 84's? Will it damage the amp? What is the difference?

The preamp tubes looking at the back of the amp from Right to Left

1. Electro Harmonics 12ax7eh
2. Electro Harmonics 12ax7eh
3. Non marked 12ax7a ("12ax7a" is the only marking on the back of the tube).
4. Non marked 12ax7a ("12ax7a" is the only marking on the back of the tube).
5. Electro Harmonics 12ax7eh

So, what do you think? Are these tubes any good? I have some 12ax7 JJ/Tesla tubes too. Will these sound better (I have enought to do the whole amp in the preamp section).

Thanks everyone! After I play through amp for the weekend, I'll post my thoughts.

The Electro-harmonics are really just Sovtek tubes. I dunno if el84's will even fit into the same socket as el34's, but they're radically diffrent in terms of spec.
Tesla is preferred over Sovtek in teh preamp/.

BTW, forgot the mention that the amp is a Chubster 40.

I believe it should have EL34's. Rivera's come stock with Svetlana tubes.

Chubster 40 tubes

There is a wealth of info about tubes for Rivera's and alot of other info at this web page. My Chubster 40 has Svetlana El34's that came with it new. I've only had it since July, but love it. It sounds great in stereo with a 65 Twin reissue, but then what wouldn't?

http://scobro.S5.com/rivera/index.htm

Scobro web site

:doh
looks like Phil M beat me to the punch referencing this same web site this morning on his thread- Needing more info about tubes:brow Well... it is a very good web site for Rivera info.

Are you sure they're EL84s? I don't think Rivera makes an EL84 amp.

my mistake. They are el34's.

electro-harmonix tubes

They are made by Sovtek, but they're higher quality. I like their pre-amp tubes much more than the Telsa tubes, and I think the EH's are the best all around pre-amp tube currently being made. I do like to put a Sovtek 12AX7LPS in the phase inverter slot since it has more depth.

Their EL-34's are really great too. Again, probably the best being made, even better than Svetlana EL-34 in my opinion.