Converting 24Vdc or 18Vdc into +/-18Vdc? Possible?

[dublin78]

I would like to add a gain stage to my "music centre" before the T-amp module.

See: http://www.diyaudio.com/forums/showthread.php?s=&threadid=115583

I have found a likely candidate but it requires a +18v . 0 . -18v supply.

There is not sufficient space avaialble for a dedicated power supply. Is it posible to convert an existing 18v or 24v supply form an smps to +/-?

 

[jackinnj]

use a rail-splitter -- this can be an opamp or a dedicated TO-92 device like the TLE2426 -- 24VDC will get you +/- 12VDC which is satisfactory for most opamps.

you can make a single ended preamp with JFET's like the 2SK170 and 24VDC will work just fine.

 

[zlast]

power supply

http://sound.westhost.com/project05.htm

 

[dublin78]

Thank you for your suggestions.

jackinnj: I will look into this. Could you provide a link to a design?

zlast: your suggestion was looking spot on until "This circuit will not work with external DC power supplies - it must use AC."

I don't particulary want external supplies (I want to keep one on/off switch).

 

[jackinnj]

it's on the Texas Instruments website TLE2426 --

you can also do something like this, but you need an opamp that can source some meaningful current (like an OPA544) -- so it will be a bit more expensive than the TLE2426:

[IMGDEAD]http://www.tech-diy.com/POWER/RailSplitter.gif[/IMGDEAD]

 

[dublin78]

Thanks again

I have found some useful info here: http://tangentsoft.net/elec/vgrounds.html

It looks like there is some homework to do this weekend.

 

[jackinnj]

Here's a simple JFET preamplifier -- distortion will be a bit under 1%

[IMGDEAD]http://www.tech-diy.com/Preamplifiers/SimpleJFETPreamp.gif[/IMGDEAD]