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previous: PAUL C Hey Steve. Yeah this amp has that ... -- 8/5/1998 7:43 AM View Thread

Re: More Gain from a Marshall

8/8/1998 4:28 AM
Steve, again
Re: More Gain from a Marshall
I'd still say check out that post inv. MV. It'll really give stupid amounts of crunch!  
    Is this the design with the dual-ganged pot? What value do you use- 500K or 1meg? While Torres wires these up with the wipers going to the driver/PI, Bruce Collins here wires them up like a stereo volume control with the wipers going to the output tube grids.  
    Although I'd put in a few of these controls with no problem, when I rewired my 65 Pro from a Torres SuperTexan kit to my own "Pro Maniac" study in plagiarism, the MV would make a loud thump when I'd turn it up to 9. After replacing the 500K pot several times and switching the wipers per Bruce's suggestion, it still made the thump so I said "fork it" and just throw in a pre-driver MV. Have you ever run across this problem? I'd rather have the post-PI MV and was even thinking of taking the back off the pot to add a stop to keep it below 9... not exactly the most scientific solution and I would lose a little bit of power from the output section.  
Steve Ahola  
P.S. I took a look last night and it was a 3k3 resistor that I ended up using on the normally grounded lead of the 1.0uF/400v mylar cap I used for Ck in the above post. Also threw in a center-off DPDT switch for the contour network to select between 560pf, 0pf and 390pF caps across the 470k series resistor.

Michael Tousek Steve,For what it's worth, ... -- 8/11/1998 12:08 PM
Dave H q{the MV would make a loud thump wh... -- 8/12/1998 6:06 AM