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Re: Need info on RAT op-amp.

9/3/2004 1:00 PM
JS
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Re: Need info on RAT op-amp.
LM 308N is the correct op-amp.  
I´ve got an unit from the early eighties with the same op-amp.  
 
MODS:  
 
Make the connection of the 2,2(4,7)uF to ground (that one that leads to a 47 ohm resistor) switchable (gives a better volume boost). Replace output trannie with a 2N5488 if it´s a BF245.  
 
Replace bias resisters for op-amp and trannie with 1M trimpots for finetuning of bias-points (decreasing this values will mellow the sound, around 800k for op-amp and 150k for trannie gives a good punchy sound).  
 
Use a Voodoo Lab Pedal-Power or something similar  
(10V DC, 150mA at least),´cause batteries are to weak for powering a RAT (increases punch, crunch and clarity).  
 
You can play with the RC-Network that goes to the feedback-loop. Replace it with 1uF,100 ohm and replace the 3,3nF cap of the tonestack with a 10nF.  
(reduces the fuzzy topend screech).