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Master Vol on a 5E3


 
3/24/2006 7:41 PM
LM Master Vol on a 5E3
I'm using a princeton chassis so I have some extra holes.Whats a good MV and presence control for my build? Thanks LM
 
3/29/2006 3:08 AM
Peter Farrington

Hi LM, I put a master vol in my 5e3 circuit, mainly to cut back power a bit and preserve an old jensen p12r. I used the post PI type, which replaces the 2 x 220k resistors between the power valve grids and ground with a dual ganged 220k pot, the power valve grids (or rather the 1k5 grid stopper resistors)being connected to the pot wipers. As a safety measure put additional 1 or 2.2 meg resistors between the wipers and ground, just in case the wipers ever go open circuit - it maintains a dc path to ground.  
This gives a surprisingly good amount of pre amp overdrive with the master low (and link channels to get another 6dB gain), with a very good neighbour-friendly tone - no buzzyness. Put a tube screamer in front for Santana sustain!  
For the presence hole, I'd put in a multi position/mulit pole switch for selecting various coupling caps feeding the regular Vol controls, or maybe selecting various v2 (after the Vol controls) cathode bypass caps.  
Good luck - Peter
 
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