Quick Q: MAX1044 UPverting á la Geofex

[cathexis]

Using the schematic from
http://www.geofex.com/circuits/+9_to_33.htm
- can I use regular polarized electrolytics for the 10uF caps, if so which way should they be oriented?

I'm going to try making a 48v phantom power supply for a mic preamp I'm working on, so any caveats regarding that are most welcome as well!
Thanks!
/Lars

[thelonious]

Yes. Orient the + side of the caps to the charge pump/diodes side, and the - side of the caps toward ground.

I'm interested to hear if others think this will be a quiet enough solution for a phantom powered mic pre, though!

[cathexis]

Thanks! If I understand correctly all caps go with the + side towards the top of the schematic then?
I'll try this with my preamp and report back. If it's too noisy I'll go back to plan A: 32 AA batteries in series

[thelonious]

Yes, in the Geofex schem the caps would go with + toward the top side.

32 AA batteries in series

Ha! You could always use a small transformer instead! But if this Stompville article is correct, you should be ok with the charge pump: http://stompville.co.uk/?p=387. He adds additional filtering before the chip.

[PRR]

> back to plan A: 32 AA batteries in series

Five 9V batteries is close-enough for any P48 mike, and a lot less parts.

[R.G.]

... and it gets that vintage sound that you can't get any other way.

[thelonious]

What do you guys think about the noise level? Should more filtering be adding to the two schematics above for charge pump use with a mic pre, or would they be ok as is as long as it's a freq boosted pump ("S" designation)?

[PRR]

Getting any kind of buzzer "quiet" is all about the details, often no-obvious details like where conductors run.

Battery is inherently quiet.