Does anyone know of a compact PCB project for a bipolar 15V or 18V power supply? I'd like to fit it with this mic pre-amp (https://expataudio.myshopify.com/products/eden-microphone-preamplifier) into a 1590B or 125B box.
Not sure I've seen any projects, im sure it can be done with 2 charge pumps, I can knock up a schematic If you like.
The L5 Preamp (https://aionelectronics.com/project/l5-preamp/) has a +/-15V power section that could easily be extracted and put on its own PCB or combined with another circuit. It runs off of 9VAC (Line6 DL-4 adapter, or you can buy them from Jameco) - not sure if that's a dealbreaker but it worked out great for this project.
something like this? im sure i have used something similar in the past, maybe breadboard it out first, if it works for you I can make you a board for cheap.
(https://s1.postimg.org/2deuo46ouj/bipolar.png) (https://postimg.org/image/2deuo46ouj/)
You have to be careful with two charge pumps, it's very possible the internal clocks could heterodyne and insert noise in to the effect.
Depending on the current requirements, you might be able to use a single chip to do the job, just do a standard charge pump doubler and then apply the same principle to the voltage inverter section.
I think there are dedicated parts as well, I recall a Maestro phaser project (the one with switches rather than pots) used one.
Quote from: darrenw6000 on October 15, 2017, 09:53:28 PM
something like this? im sure i have used something similar in the past, maybe breadboard it out first, if it works for you I can make you a board for cheap.(https://s1.postimg.org/2deuo46ouj/bipolar.png) (https://postimg.org/image/2deuo46ouj/)
Super generous offer darrenw6000.
Quote from: Scruffie on October 15, 2017, 10:44:42 PM
You have to be careful with two charge pumps, it's very possible the internal clocks could heterodyne and insert noise in to the effect.
Depending on the current requirements, you might be able to use a single chip to do the job, just do a standard charge pump doubler and then apply the same principle to the voltage inverter section.
I think there are dedicated parts as well, I recall a Maestro phaser project (the one with switches rather than pots) used one.
And thanks for the advice Scruffie. Not sure of the design implications, but I've definitely run into heterodyning and found the noise add super-frustrating.
I'll happily fund a prototype. Send me a PM? I'm no circuit-builder or PCB designer. Seem to have my hands full as board populator and hack guitarist. :-[