Is a rebias needed if using the same tubes?

[maddnotez]

I just bought a used amp from GC. They packaged the tubes seperate to protect them.

I intend to use the same tubes. If I just simply put them back in correctly will there need to be a rebias?



The amp is a VHT Putbill G 100 CL if that makes any difference.

[pontiacpete]

I would put them in and watch them closely and listen to how they sound. If you can check the bias then why not.

[maddnotez]

I cant check no meter. I guess I need to buy one

[Jazz P Bass]

In my opinion there is a wide variation in tubes that an amplifier will tolerate.
Of coarse it does depend on the circuit topology.
What you would like to avoid is the two extremes.
If the tubes draw too little of a current at a set bias, you will hear crossover distortion.
If they draw too much current then you may have a situation where the tube(s) may red plate.
The first one you can hear.
The second one you can see.

[pdf64]

But they won't show visibly red plates until they're way over their max dissipation, maybe 200%+.
Best to get it checked, then you know that it's sounding it's best and tube life won't be curtailed.
There's nothing to say that it was set up right when GC had it. Pete.

[riz]

Well, if they are THE SAME TUBES, not the same type, but the exact tubes that were in it, taken out, packaged, then re-installed, then a re-bias should not be necessary, IF the bias was set properly beforehand. But it's always good to check.