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Re: Butthead, God, and Retribution

6/6/2000 5:11 AM
Carl B.
Re: Butthead, God, and Retribution
You've got me interested in those "racey" voltages for EL84 plates/screens.  
What are you running the plates at for that, 10 watts idle, or pushing the envelope to the full 12 watts at idle?  
I've an old Reverb-Rocket II that either needs some 7591s, or an EL84 transplant. The voltages there aren't even as high: 370Vdc or such, if I remember correctly.  
The EL84 may be a good candidate to get that old girl running again. (Thinking an adapter socket with a cathode resistor/cap pair to help with the biasing a bit. Hopefully, no mods needed to the amp itself.)  
Thanks for the note, Reb.  
- Carl
6/6/2000 1:37 PM

Actually, they are fixed bias, and Traynor never put in a bias adjustment pot!!!!! *laugh* OUCH! I like to run them myself following the rule of thumb, 70% of Pa(max) so 70% * 12W = 8.4W so bias them at about 21mA if you are pushing 400v. I will repeat till i'm blue in the face, however, I do NOT recommend this with Sovtek EL84s!! Get a set of old Mullards!! OR if you are REALLY lucky a pair of 7189s, which I tend to like a bit better, they are a bit creamier to my ears, and a LOT more robust.... the Mullard EL84's (sometimes labelled as Phillips 6bq5s), from what I've seen are more like a 7189 than most american made el84s or the russian el84s.

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