Can I damage my 5881's with pentode/triode switch

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LooseChange
Senior tube assistant
Posts: 221
(3/24/04 11:51 am)
 Can I damage my 5881's with pentode/triode switch??
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 I added the "Pentode/Triode" switch to my Super Reverb. I kept the 470ohm screen resistors in there. (Plates=465v, Bias=30mA) I have had some troubles with 2 sets of output tubes. Coincidence or not? Should I up the Screens to the 1k 5w resistors?? Thanks!

Edited by: LooseChange at: 3/25/04 5:17 pm
 
6G6
Junior tube assistant
Posts: 145
(3/25/04 7:36 am)
 Re: Can I damage my 5881's with pentode/triode switch??
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 Use the 1.5K screen resistors and keep the bias fairly low.
5881s are intended to be more rugged, so that should help also.
 
Moosehead2
Junior tube assistant
Posts: 52
(3/25/04 1:58 pm)
 re
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 i am also thinking of building a super reverb with a pent/tri switch. How do you like the results?
 
LooseChange
Senior tube assistant
Posts: 222
(3/25/04 5:17 pm)
 Re: re
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 Excellent. A bit lower volume and a b it warmer. I have a few gain stages added and at times it is too loud. This helps.
 
Moosehead2
Junior tube assistant
Posts: 55
(3/25/04 5:35 pm)
 re
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 Thats what i thought. I guy asked me to build him a super reverb with the half power option. I believe he thinks that this is going to give him a big cut in volume for playing smaller venues. He'll probably be better off with a master volume, although having both would be cool too!
 
bluesbear
Hey get your own solder
Posts: 353
(3/26/04 8:44 am)
 Re: re
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 This is something I've never tried. Is there a schematic or drawing or text description somewhere?
Thanks!
Dave
 
Moosehead2
Junior tube assistant
Posts: 57
(3/26/04 2:00 pm)
 re
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 i got my info from Kevin O'connors "The Ultimate Tone".
 
LooseChange
Senior tube assistant
Posts: 223
(3/26/04 6:55 pm)
 Re: re
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 Not a difficult thing to do. Just connect the screen to the plate through the screen resistor.
The screen resistor is removed from the screen supply and those leads are connected to the plates. On 6L6 and compatibles: the plate is pin 3 and the screen is pin 4.
This mod is as public domain as they get. Someone, hopefully, can point you to a link.
 
 
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