New tubes

tragictravisty

in my valveking. the stock ones blew after 6 months (i play allot, and they problably werent great) anyway, i pay 60$ (thats right 60. for some reason my music shop stocks only groove(expensive as ####) tubes) for kt66's to replace 6l6gcs. they fit fine and sound great, but i didnt have them biased. what am i risking if anything?

by the way, the amp is much clearer, the distortion sounds better, headroom is slightly increased but not much, and it is very dynamic. when i turn it up, it sounds better, and rather than getting muddy and flabby, it remains clear.

also, the tubes had a rating of 5 by groove. this means they have moderate headroom.

Mustang-Pete

If they sound good then I don't see what the problem is really...

Richie

It sounds like you got lucky and it doesn't need biasing. I'd treat it as a one-off. When you next come to change tubes, I'd get it biased, the next set you get probably won't have the same rating.

Basically biasing is evening out the voltage according to what the tube can handle. Too little and it'll sound crap, too much and the plates will (eventually) melt. A way to check if it's okay is opening the amp up and (without touching anything inside it!) switching it on, and seeing if the plates under the tubes start to glow red at all. If they do it means too much voltage.

I really need to change the tubes in my Selmer at the moment, I bought the matched pair or EL34s for it but 'cause it's an old amp I'm terrified of not getting it biased and it blowing up or something.