mrhat said:
Hey guys, i just got a used rectoverb combo off ebay, and when i got it in today,its kinda noisy and i think one of the powertubes might be bad, it makes a kinda buzzing noise until i touch it with my fingernail, then it stops. is this for sure a powertube problem? this is my first tube amp, so i am a little in the dark about that stuff. also, if i need to replace the powertube, since the rectoverb has an autobias, can i use most any 6l6 matched pair in it? sorry about all the questions
If the tubes are making buzzy noises, that's normal. It's the effect of the heater current being applied to the power tubes.
If you're experiencing a buzzing noise coming from the speakers and it subsides when you hit the strings on your guitar, you've got a grounding problem that needs to be worked out.
Lastly, the Rectos aren't autobiased. They're fixed biased amps in which the bias (grid voltage) is set with a non-adjustable resistor. Amps with bias pots are fixed bias amplifiers as well, but the bias pot is a variable resistor.
You'll learn more as you read more.
As far as current production tubes in a Recto go, I like EH and 9th Generation Chinese 12ax7's.
As far as power tubes are concerned... SED 6L6GC's, SED EL34's, EH EL34's, JJ 6L6GC's (these typically run too cold), Ruby EL34B-STR's (these are awesome) and JJ E34L's or JJ EL34's. I'm sure there are others that I've tried that I'm not thinking of at the moment.
As far as The Tube Store is concerned, I don't like them. Sure, they have a nice assortment of tubes, but they don't test them as well as some other vendors do.
Here is who I use:
Lord Valve - 303-778-1156
Doug's Tube - www.dougstubes.com
KCA NOS Tubes - www.kcanostubes.com
Dale