Tube Replacement and Biasing

[charvel750]

Guys, if I currently have Groove Tubes EL-34R rated at 6 and correctly biased, if I put in new Groove Tubes of the same model and hardness, will they still need to be biased? Or do the same brand/hardness have a consistency that does not require biasing?

[DonP]

According to Groove Tubes, you shouldn't need to check / set the bias if you stick with the same model and hardness.

[Jayster]

that is correct DonP ,a matched quartet (similiar rating )will not require re-biasing

[charvel750]

Thanks, guys. Does this go for all tube makers? Or only Groove?

[toejam]

Thanks, guys. Does this go for all tube makers? Or only Groove?

I know Mesa/Boogie states the same thing, so I would assume it goes for all.

[Rsmacker]

Thanks, guys. Does this go for all tube makers? Or only Groove?

Depends on the company. Groove Tubes are expensive, and that's because they spend the time and effort grading and matching valves. WingWong Valve Company, Peking, might not be quite so dilligent.

The WingWong valves might be roughly matched, but not to the degree GT do them - they probably won't be graded ("hardness"?).

So long as the valves are matched as a quartet (or pair), you won't do any harm, but it might not sound the same as your previous GTs. The amp might need to be slightly tweaked to run the WingWong set, say, slightly hotter or whatever, to get the same grind.

The thing with the GTs, you pay the cash to get exactly what you had before. (Don't know what other valve suppliers do detailed gradings, apart from PM Power Tubes)