#1
I recently bought a Rivera K-TRe 120 on Ebay. It came with bad power tubes. A friend sold me a set of Mesa EL-34's he had. The amp sounds really good with them. I did not rebias the amp. I once heard you don't really need to rebias EL-34's. Is this true? It seems odd. I want to know the full potential of this amp but, where I live the nearest repuatable amp tech is almost two hours away.

Another option I have is to order tubes from Rivera. The original tubes had their test numbers written on the tube. I could order a set with the same test specs but Rivera charges a whopping $140 for a quad of el-34's. However, when you subtract the cost of getting a bias job and my time and gas, this may be a good option.

Any opinions would be appreciated.
#2
whenever you change power tubes in a fixed bias amp, you must rebias it. exceptions include certain brands that rate their power tubes, so if you'd be safe ordering the a new set of tubes rated the same as your old set.

you don't need to pay $140 for new tubes if you don't want, but i suggest you either learn how to bias your own amp, or get someone to bias it for you. your amp can suffer badly by not being properly biased to the tubes.
Gibson SG Standard + 18volt EMG-81 & 85
Mesa/Boogie Mark IV + Recto 2x12
Keeley Modded BD-2
Vox V847a
Quote by one vision
Bureaucrats gonna crat.

Recognised by the Official EG/GG&A Who To Listen To List 2008
#3
Thanks for the reply. I'm not really comforatable attempting to bias by myself. Maybee I'll get the Rivera tubes.
#4
ah, i see. well that may be a decent idea now, but what about in the future? is anyone you know familiar with electronics? biasing is pretty simple to learn, and even easier to do.
Gibson SG Standard + 18volt EMG-81 & 85
Mesa/Boogie Mark IV + Recto 2x12
Keeley Modded BD-2
Vox V847a
Quote by one vision
Bureaucrats gonna crat.

Recognised by the Official EG/GG&A Who To Listen To List 2008
#5
I thought of buying the Riveras and sending them to Dougstubes to have them test them so I could buy from them in the future without needing to bias. I talked to them on the phone a while back and they said their test numbers would not be relative to the Rivera numbers. I did not think to ask if they would test the Riveras to cross reference a set for me. I believe thoose tubes would only costs half as much.