confusion over mega-boost PAB resistor values

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ER
Posts: 649
Joined: Thu Sep 18, 2008 6:38 pm
Location: NorCal

confusion over mega-boost PAB resistor values

Post by ER »

Bluesmaster schematic shows a 22M on the unused relay half, and a ~75k across mid to ground when relay is open with a 15k or 25k mid pot. This doesn't show up however on the layout instead another 22M resistor is there.

What's up? Is the extra resistor just to tame the boost jump? Is it related as a voltage tail, or just a dB thing?

What value would I use to ground with a 100k mid pot? I'm thinking roughly three times ~270k but would like to know if there's a specific formula for such things or if it's even necessary. I'd like to bypass the clean tonestack tone wise as much as possible yet still have a usable boost without a huge jump in output.

I also have an on/off pot on the mid so I can put the resistor to ground before or after this and or the relay to have megaboost by foot and complete bypass at the amp but I'd kind of prefer to have the best compromise of both accessible by footswitch.

Will have a second megaboost on the HRM stack but this comes off a 500k bass pot to ground so I need to figure that too. HRM also has a 100k mid with on/off switch available at the front panel so mid turned all the way down breaks ground like it will on the clean stack.

Thanks, ER
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