Author Topic: Quick Q: MAX1044 UPverting la Geofex  (Read 1884 times)

cathexis

Quick Q: MAX1044 UPverting la Geofex
« on: April 03, 2014, 02:34:35 PM »
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

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #1 on: April 03, 2014, 03:39:40 PM »
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!
« Last Edit: April 03, 2014, 03:48:03 PM by thelonious »

cathexis

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #2 on: April 03, 2014, 03:47:41 PM »
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

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #3 on: April 03, 2014, 03:51:13 PM »
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

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #4 on: April 04, 2014, 02:19:44 AM »
> back to plan A: 32 AA batteries in series

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

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #5 on: April 04, 2014, 10:29:19 AM »
... and it gets that vintage sound that you can't get any other way.
 :icon_lol:
R.G.

Quick IQ Test: If anyone in a governmental position suspected that YOU had top-secret information on YOUR computer, how many minutes would you remain outside a jail cell?

thelonious

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #6 on: April 04, 2014, 01:19:07 PM »
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

Re: Quick Q: MAX1044 UPverting la Geofex
« Reply #7 on: April 04, 2014, 06:23:25 PM »
Getting any kind of buzzer "quiet" is all about the details, often no-obvious details like where conductors run.

Battery is inherently quiet.
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