Gain changes how-to

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bluesbear
Hey get your own solder
Posts: 328
(2/16/04 1:25 am)
  Gain changes how-to
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 Hi. Could someone tell me how gain is manipulated (up or down) in a standard Fender type gain stage like the one in this link?.

members.aol.com/blusbear/gainstages.jpg

Thanks!
Dave
 
Rotting27
Junior tube assistant
Posts: 118
(2/16/04 3:26 am)
  Re: Gain changes how-to
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 A quick, not-so-indepth answer is: Increasing the value of the plate resistor or decreasing the value of the cathode resistor will increase gain. Decreasing Ra or increasing Rk, likewise will decrease gain.
 
ganzonimx
Hey get your own solder
Posts: 382
(2/16/04 10:44 am)
  Re: Gain changes how-to
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 Dave!

The AX84 project pdf-file gives a good and easy to follow explanation of calculating gain in a common triode stages. You'll find the article at the top of the page in the "read this to learn about..." thread.

Cris
 
LooseChange
Senior tube assistant
Posts: 209
(2/16/04 6:44 pm)
  Re: Gain changes how-to
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 Mess with the cathode resistor and the Bypass cap first. Leave the plate resistor at 100k. I like to switch a bypass cap in and out for a gain boost. You can easily and safely put a 10k pot on the cathode resistor and clip caps in and out to learn a lot. If you mess with the plate resistor, your messing with 150 to 300v!!! Many gurus out there think the 100k is perfect.
 
bluesbear
Hey get your own solder
Posts: 329
(2/16/04 6:53 pm)
  Re: Gain changes how-to
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 Thanks! That gives me all I need to experiment.
Later,
Dave
 
 
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