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previous: BMann I had no idea the Marshall 50-watt ... -- 9/23/2000 6:59 PM View Thread

Re: NS PT a tad powerful, eh?

9/25/2000 4:22 PM
Gil Ayan
Re: NS PT a tad powerful, eh?
"What worries me are the plate and screen voltages, 485 and 482 respectively, on Svetlana EL34's. "
I am not sure what makes you feel uneasy about this? The rated plate voltage of the EL34s is 800VDC, so what's 480VDC? Not much to speak of.... Put it this way, any Fender twin with 450VDC on the plates is a lot closer to the 6L6's 500VDC maximum plate voltage than your EL34s... :)  
Actually, those are low voltages in comparison to some other amps out there. For one thing, the real Plexis we hot, and for example the Groove Tubes Soul-O 75 amp has a whoppinh 520VDC on the plates... and they "advertise" their amp can be used with 6L6s as well. Of course, it can be used with 6L6s without any reported problems that I am aware of.  
"The worries are such as, what's a good bias figure, can the screens take that much power before meltdown, etc. No, I incorporated a master volume, haven't dimed it yet, but sheesh! Even on 2 this amp's monstrous!  
Again, I am not sure whether you meant to write that your plates have 580VDC instad of 480VDC? Put it this way, if you were expecting 450VDC, you have increased the voltage by 6.7%. Any "target idling current" you had in mind for the expected plate voltage would have to be decreased by the same amount to get the same idling power figure....  
I would say that since the dissipation of the EL34s is around 25W, to get half poer at idling you want to aim for around 26mA or so.  
"Advice anyone? Especially on what PT to use _next_ time?"
It all depends what you're after... As a Plexi replacment, I believe the New Sensor is a GREAT piece of iron -- I used a New Sensor MPT 100W in one of my amps, and it just so happens to be the one I think sounds best. :)  

BMann I just never recalled working with ... -- 9/26/2000 10:35 PM