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6L6s and GZ34?

3/11/2002 5:34 AM
6L6s and GZ34?
Hi Bruce,  
Is it possible to use 6L6s and a GZ34 in this design? I'd like to try it. I've got a 10 watt 270 ohm bias resistor; is there anything else needed to make it work?  
Also, I read in the Tone Quest Report of a 5E3 using a larger OPT (from a Pro, I believe) for more power. Is this possible, or desirable? Thanks for the answers!  
3/13/2002 6:54 PM
Bruce /Mission Amps

Yes that 270ohm 10 watter wiil work.  
If you have a smallish PT, I'd prefer not to use any hollowstate recitfier when doing this mod as there is an additional high voltage load and filament supply load put on the power tranny when the 6L6s are used and biased up to about 18-20 watt range. Using a SS rectifier unloads the PT's VA a small amount and it will run slightly cooler for it.  
In order to get a little power supply sag, I'd consider using a 120-150 ohm power resistor in the grounded center tap lead of the power tranny's high voltage secondary.  
My first attempts at a 6L6 version of the 5E3 used a standard reissue Pro Reverb OT.  
I've since had custom ones made with a different primary zed and a 4 and 8 ohm tap too, but the old Pro OT still sounds pretty darn good!  
3/18/2002 1:24 PM

Bruce help me fix up a 6L6/GZ34 and it's nice. I think it's Bruces Blue Stone OT that we used and it's nice. That Cathode resistor does stay pretty hot but it's fine. Bruce have you tried any other OT's besides those like an OEI ?,  
3/19/2002 6:12 AM
Bruce /Mission Amps

"Bruce have you tried any other OT's besides those like an OEI ?"
Oh yeah... too many.  
I have not used the OEI OT in the Bluestone Super amp though. You'd have to run it in a mismatched load to get the zed up high enough for cathode biased 6L6s.  
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