Best-sounding attenuator?

[RLee]

Re: Best-sounding attenuator?

Just wanted to follow up and let you know the results of putting the Lar/Mar PPIMV in my marshall 1987x head... in a word, the result was astounding. I don't need any attenuators or power scaling or anything except this amazing master volume mod. I get fantastic sounding plexi goodness at bedroom levels. I was not actually expecting it to sound this good, but it does.
I'm a happy plexi owner now! :approve:

 

[Gr8Scott]

Re: Best-sounding attenuator?

Can you give us a gut shot of the Lar/Mar PPIMV? I want to see what it looks like. What parts came with this MV?

 

[RLee]

Re: Best-sounding attenuator?

Can you give us a gut shot of the Lar/Mar PPIMV? I want to see what it looks like. What parts came with this MV?

Some pics, showing the two shielded wires coming from the pcb where the two 220k bias resistors used to be, going to the dual 250k pot, and two shielded wires going from the pot to the EL34 grids. The shielded wires are easy to spot with the green and orange heatshrink. You can see I replaced the two PI coupling caps with orange drops. With the pot all the way clockwise, this mod is effectively bypassed, meaning the amp operates as if it were stock, without a MV. I used single-conductor shielded cable for max isolation; it's a bit easier if you use dual-conductor cable. I didn't order the kit from metroamp -- I just ordered the dual 250k audio pot from mouser, since I had everything else already. But the metroamp kit is a good deal, if you need everything.

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