Charge pump advice for PNP germanium Big Muff Pi

[lmorse]

I have just successfully bread boarded a germanium transistor Big Muff Pi. I wanted to build in a charge pump to reverse the polarity for the positive ground PNP transistors (+9v).

I have never built a charge pump before, and have no experience with any of the IC's. I have had a brief look at the MAX1044 and the ICL7660 (which seems quite a bit cheaper than the MAX1044).

Which IC will suit my project better? Can anyone sum up the pro's and con's of the various IC's?

Any advice, schematics etc. for a suitable charge pump would be appreciated

[njkmonty]

have a squiz at these...

http://www.madbeanpedals.com/projects/Rangemaster/Rangemaster2014.pdf


http://www.madbeanpedals.com/projects/RoadRage/docs/RoadRage2014.pdf

[Govmnt_Lacky]

DO NOT use the MAX1044. If you plug in a power supply that is putting out more than 10.00000000000000001V it will FRY the chip! 

Better off going with the ICL7660 or the TC1044.

Better yet... go all out and use the LT1054 which is good at least up to 12VDC and ~100mA

[italianguy63]

Greg's got it!  I emailed you some helpful docs.  MC

[Mark Hammer]

All charge pumps operate off a clock.  The 1044 has the option to double the clock frequency, providing both smoother power, but also bumping any ripple up into a higher range so that you don't hear it.  This is helpful if you are using it to power anything that either uses a clock, or is intended to have very wide bandwidth and needs to be clean.  The BMP is none of those things, in which case the less costly 7660 or 7662 is very likely fine for the job.

[thehallofshields]

I'd be interested to know if swapping for G
e in a BMP would yield anything other than lower gain.

[thelonious]

I often use the ICL7660SCPA. There can be variations in what letters come after those numbers. The two you care about are the S (boost to higher frequency operation) and the P (DIP package for through-hole soldering). The other letters don't matter for our purposes.

If I were you I'd first try the Road Rage like njkmonty said or possibly the tagboardeffects voltage inverter. My experience has been that when I'm running a -9v inverted pedal full-out into a already cooking amp or another drive pedal, I get high-end hiss and hash. This is the inverter circuit I use:


It might be overkill for some applications, but it's really quiet.

[Davelectro]

ICL7660SCPA.

This. Works like a charm.

[lmorse]

I'd be interested to know if swapping for G
e in a BMP would yield anything other than lower gain.

I got hold of some high gain (hfe 320 - 390) germanium transistors. I don't have a regular BMP to compare it to, but I can say it sounds awesome! I added a few tweaks (a switch to knock out the second clipping stage diodes, and a switch to change the capacitor value in the tone stack to remove the scooped mid). A great range of sounds, some great harmonics.

I often use the ICL7660SCPA

I have just ordered a batch of these from China, thanks for the schematic!!!!