glip22":e3gqbk95 said:
Laymen's version as I don't get into all the geek speak on most things. It's not a constant if there are tubes installed. It will also fluctuate with the wall voltage. The tubes pull current in relation to the bias which will lower the plate voltage. It should vary with output but only in relation to the tubes current draw increasing as you turn the amp louder.
First, thank you for replying. Now, so what you're saying is if I keep the main output at say half way up there is less chance of blowing the tubes by excessive plate voltage? Am I understanding this correctly? Any ballpark idea of how much less plate voltage there would be with the volume half way up as a percentage of the max plate voltage with the volume up all the way?
glip22":e3gqbk95 said:
Tubes are rated but most can handle more. The older tubes were generally rated higher. I wouldn't really be concerned unless your amp is putting out well over 500 volts. Higher plate voltage may make your amp brighter, punchier, less sag. I like it!
I have 2 6L6GC amps left - a Fender HRD (allegedly 430 plate volts) and a Boogie Trem-O-Verb (depending on the settings between 415 and 530 plate volts). I want to try my vintage Mullard EL37's in these amps. EL37's are allegedly rated up to 400 plate volts (although according to some sources up to 800 v). I suppose the Fender with its 430 v should be safe for EL37's? Especially since I never turn it up past 10 o'clock anyway. What kind of damage could occur if things don't go as planned? Is there a danger of damaging the transformer?
As for the Trem-O-Verb the tube rectifier mode supposedly drops the plate voltage to 415 v, which I guess should not be an issue for EL37's, right? Even in the bold setting?
I realize these are all hypothetical - just would like your personal opinion.
glip22":e3gqbk95 said:
There are some transformers that have high and low plate voltage taps that can be put on a switch or just wired for one. There are other ways to lower your voltage. It will lower the bias usually too much unless you have it as a constant and can rebias for that specific voltage. It can be tricky to do but it can be done. I have seen it done on a switch where the bias also lowered when selected. Paul Cochrane had this option on his Colonial amp if I remember correctly.
I'm not looking to mod my amps - just want to try these cool looking tubes in them.