cmos DC-DC converter for capsule bias

Hi,

I just finished building a mic with Dale's C-37 capsule. As I thought it would be, the noise floor is too high without a DC-DC converter.

I've been messing around with a 74C14 CMOS Logic Hex Schmitt Trigger. I can get it to multiply the voltage, but I can't seem to get the current draw low enough. I know others have already posted some about this. I've read these posts but I'm still stuck. Just so you know, I did ground the input of all unused gates on the inverter.

Is there anyone who might have some pointers for me?

Thanks!

-Josh

DC converters are a bitch.

First of all, make sure, the output of your converter doesn't draw any current to speak of.
Also, try different brands of CMOS chips. I used 40106 chips, btw. Grounding unused gates didn't do much for me.

I recall there's an article on the Gyraf-site:

http://www.gyraf.dk/schematics/Voltage_multipliers_with_CMOS_gates.pdf

Read and then think of another solution 
Non unfeasible, but like Rossi said, it's nice to live without these.

Hard slewing of CMOS gates will always take lots of current.

The CMOS stuff does work, and when you get it right, it uses very little current. But does take a while until you get it right, and different chips perform differently. Also, you have to be careful about HF-crap. Put some distance between the CMOS oscillator and the high impedance area and use good filtering on the polarization voltage.

Clintrubber already posted the Gyraf link
Here's some more Stuff on CMOS and other DC-converters: http://www.sdiy.org/oid/mics.html

Thanks for the info!

I actually just found a leakage path from the capsule bias voltage that I had overlooked. Oops. I took care of that and now the mic is much quieter. I may still put together a DC-DC converter, but for now I'm going to use the mic for a while to see if the noise floor is low enough. Thanks again!

-Josh