Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: stigg on December 23, 2011, 12:46:23 PM

Title: phantom power
Post by: stigg on December 23, 2011, 12:46:23 PM
I have an ultrasound DS3 acoustic guitar amp combo
and apparently it doesn't have phantom power.
I would like to know if there's a way to modify the amp to supply it.
I could buy an external di box but I'd rather have it self contained.
Has anyone tried this?

s :)

Title: Re: phantom power
Post by: J M Fahey on December 23, 2011, 02:35:14 PM
I think it can be done.
google for some PA mixer schematics (Peavey, etc.) and copy what you see.
Basically you take whatever voltage you have available (many just use the +15V rail which powers the Op Amps) or lower the higher voltage power amp rail to, say, +24V with a regulator.
You feed that to both Hot pins in the XLR chassis connector through suitable resistors.
You´ll also isolate that DC voltage from the actual board input with a pair electrolytics, and add a switch to enable or not the Phantom power.
As I said, mimic what PA mixers do.
Not *that* complex.
Title: Re: phantom power
Post by: stigg on December 24, 2011, 01:33:52 PM
Thanks and Merry Christmas:)