Members CoolDrum3 Posted September 4, 2012 Members Share Posted September 4, 2012 I am building an multi-effect pedal that contains both + and - boosts (Rangemaster based and LPB-1 based) and a Red Llama clone. I want to power with a single 9V. However, I'm unaware of how to reverse the polarity to power the Rangemaster. Also, how would I hook the Rangemaster + ground up to the ground of the rest of the box? Do I need to run an entirely seperate ground? Before it's suggested, no I don't want to rework the Rangemaster to run NPN, I already have NOS Mullards! Link to comment Share on other sites More sharing options...
Members t_e_l_e Posted September 4, 2012 Members Share Posted September 4, 2012 you can't mix positive and negative grounded pedals, it will short on the ground and nothing is workingyou need 2 power supplies (batteries), or a power supply with 2 isolated outputs. there is nothing you can change about it Link to comment Share on other sites More sharing options...
Members amp_surgeon Posted September 4, 2012 Members Share Posted September 4, 2012 I am building an multi-effect pedal that contains both + and - boosts (Rangemaster based and LPB-1 based) and a Red Llama clone. I want to power with a single 9V. However, I'm unaware of how to reverse the polarity to power the Rangemaster. Also, how would I hook the Rangemaster + ground up to the ground of the rest of the box? Do I need to run an entirely seperate ground? Before it's suggested, no I don't want to rework the Rangemaster to run NPN, I already have NOS Mullards! You can't just reverse the polarity. You've got 9 volts coming in. One side or the other is usually connected to ground. If you ground the positive side then you've got -9V to power the Rangemaster. If you ground the negative side then you've got +9V to power the LPB1. You can't get both without some extra circuitry. Maxim makes some inverting regulators that will provide a negative voltage out with a positive voltage in. The MAX759 would probably do what you want. It's basically a little switching power supply on a chip. It would need a few additional components, like a couple of zener diodes, some caps, and a filter coil. Link to comment Share on other sites More sharing options...
Members cryptosonic Posted September 4, 2012 Members Share Posted September 4, 2012 Madbean has a little board for this, the road rage. Sabrotone has a vero layout as well. Link to comment Share on other sites More sharing options...
Members CoolDrum3 Posted September 4, 2012 Author Members Share Posted September 4, 2012 Yep, that's what I was referring to...something like that. I figured I have to put some kind of zener rectifier in there somewhere. Maybe I'll check out the 'packaged' solutions cryptosonic suggested to save some time, however. Link to comment Share on other sites More sharing options...
Members V Posted September 4, 2012 Members Share Posted September 4, 2012 Well, you could go the zvex route and wire the PNP "upside down" so its positive side isn't connected to ground but is connected to +9v instead. That's how the fuzz factory is done with a mixture of NPN and PNP. You also do this in a differential amplifier octave generator. Might be a little bit noisier but it's doable. http://solgrind.files.wordpress.com/2008/02/zvex-fuzzfactory-rev1-1.gif eg Link to comment Share on other sites More sharing options...
Members analogmike Posted September 4, 2012 Members Share Posted September 4, 2012 We put one of thegigrig Virtual Batteries inside pedals like the Mini Jimi which use both polarities. Clean, fast, high quality solution. Link to comment Share on other sites More sharing options...
Members V Posted September 4, 2012 Members Share Posted September 4, 2012 We put one of thegigrig Virtual Batteries inside pedals like the Mini Jimi which use both polarities. Clean, fast, high quality solution. Might be a bit costly for a DIY build though. Link to comment Share on other sites More sharing options...
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