From: tubegardenia@gmail.com   
      
   On Monday, April 6, 2020 at 1:11:29 AM UTC-5, Xtrchessreal wrote:   
   > I have a DIY amp built to Marshall 2204 circuit specs that is about 15 years   
   old now.  I use it at my gigs. I want to experiment a bit.   
   >    
   > A couple ideas I have barely researched but have in mind:   
   >    
   > Add a post PI volume pot - Without seeing a schematic I believe this would   
   allow clipping in the PI while attenuating the AC signal from the output tubes   
   without affecting the negative bias.  The result being a nice control over   
   clipping distortion    
   without having to go deaf.  There may be more examples but I think Triode   
   Electronics has a Mod like this for sale.   
   >    
   > Attenuating the NFB - Simply adding a pot to do this seems easy but I know   
   there are risks with oscillations.  Any suggested pot values to use safely?    
   What about caps to help filter RF oscillations?   
   >    
   > I'm curious what known issues there may be that could damage my amp,   
   assuming the mods are done properly.  I have an O-scope and DMM to test with,   
   what should I be looking for and where?   
   >    
   > I wonder what other mods I could play around with to achieve some amp   
   distortion?  I have room to add more preamp valves.   
   >    
   > Anyway I ain't got money but I do have time - quarantine time.   
   >    
   > Thanks for any direction to help make this possible.   
   >    
   > X   
      
   synth@metasonix.com   
      
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