Preamp for GGG 20x0 poweramp

[maiko]

always wanted to build an amp with more bang so i though the General guitar gadgets 20x0 amp
would fit the job. 

Im planning on running a TDA2050 with maybe 24 volts or higher.

im thinkng about using this as my pre amp.

http://www.eleccircuit.com/guitar-preamp-over-drive-using-12au7/

But got questions
1.) why use caps with very high voltage ratings 400v when this circuit is suppose to be 9v powered
2.) can i use a 12 ax7 and run higher voltage thru it.  just separate the heaters to 12.6?

[PRR]

It wants BI-POLAR +/- supply, and it must not exceed 25V each side (50V total). Do you know how to do that?

Tube-geeks tend to stock part-uFd caps only in high-volt spec. Yes, in this case you can use 25V parts. May not save a lot of money.

The 12AU7 is really the better choice here, until you get far over 50V.

Now you need 12V heaters, +/-20V for the TDA, and a small +50 or so for the tube. That's a lot of power supply parts and labor. I'd lean to just +/-20V, put 19V on 12AU7 plates, use a 5W resistor to drop power for heater.

[maiko]

prr thanks for the quick reply

Yup   already laying out a pcb for the bi-polar power supply     

will probably jud mock this up and see from there where it goes.