Using two gain pots in a Dr Boogie.. how is it done?

[ghostsauce]

Heya, I'm going to build a DR Boogie for a friend and he wants both the 1M and 500k gain pots in there, with a switch to select between them.. hhhoOOOW is that done?  I can't figure it out.  Here's an example of one somebody else posted in the pictures thread, but I can't find anywhere that explains it.

My new -Version B- Dr. Boogey




It features an on/off/on switch that changes the input capacitor value between 0,33uf/none/22uf for that Raw/Vintage/Modern effect, as well as a DPDT switch that reduces the value of the Gain pot from 1M to approx. 200k

All in all, a relatively successful build (ok, i'm a little dissatisfied with the 'A/B Channel' effect but i might process it further). Also, after looking at these pics i think i'll eventually go with black knobs on this one :-)

ps. I'm feeling soooo 'small' after browsing over hunderds of pages in this thread  

[ghostsauce]

Heh, I should be more clear... I'm using gaussmarkov's pcb layout again. (just woke up, mmkay)   I'd love to believe it's as simple as routing the 3 gain leads through the DPDT but I've no idea

[auden100]

I could be wrong, but in the example you've provided, it looks like the person just made the footswitch add a resistor to parallel the gain pot. A quick calculation shows that adding a 250k resistor in parallel with 1M provides 200k ohms.

Another way to do the same thing, but make it adjustable might be to use the DPDT switch to move to between two pots of your choice in value. Then the amount of Gain reduction would be whatever they were set at.

Increasing the resistance of the gain pot is what increases gain. So anything you can do to adjust that resistance is going to change the gain. Switching between pots or adding/subtracting with parallel and series resistors will do this.

[Güero]

Option for 1 more POT




Option 1POT

[ghostsauce]

Hmm, thanks for the help guys but I think this might be too complicated for me. I can't yet read schematics :/  I don't really like the way the original guy did it having it run off the same pot, because you can't preset them like the channels on an amp. Maybe I'll just leave the 1M in and save that for next time.  Appreciate the assist though, thank you!

[boogietube]

Here's a couple of diagrams:


IMG]http://i94.photobucket.com/albums/l86/boogietube/2xvolumeLEDs.jpg[/IMG]

[boogietube]

[deadastronaut]

i think you would be better off with 2 volumes and 2 gains..and 2 3pdt's...much more versatile...

ive seen a diagram on here somewhere...i'll take a look.

[paulyy]

Here's a couple of diagrams:


IMG]http://i94.photobucket.com/albums/l86/boogietube/2xvolumeLEDs.jpg[/IMG]

Thanks for this layout. I was trying to figure out how to do that to my dr boogie. Thanks boogietube .

[frequencycentral]

Here's a couple of diagrams:


IMG]http://i94.photobucket.com/albums/l86/boogietube/2xvolumeLEDs.jpg[/IMG]

Thanks for this layout. I was trying to figure out how to do that to my dr boogie. Thanks boogietube .

Thanks Rick! 

[boogietube]

THANKS RICK!

[askwho69]

is modern 1uf and 10 uf for vintage? is that correct? Sorry need to ask . . . this thread gonna go up up up!

[jmwreck]

maybe this will help

http://beavisaudio.com/techpages/Switches/

I wanted to try this