Experimenting w/cnvrtg audiotube monoblock amp to Guitar amp

[dallendo]

Hello,

I may have misposted this in the wrong spot, so am reposting it here:

**I want to experiment with a little PCB preamp I built by powering it within the S5 Electronics K-12M Tube Amp Kit/Mono version version.

For anyone familiar with this circuit/kit, (I can't find an online Schematic to link to, sorry), *(?) what is the best place to power something not originally designed into the circuit, all things considered, on this PCB Audio Tube Amp circuit, if you know it/have built this kit. This would integrate a/this preamp to power a turntable, (guitar :)17mA input I understand), etc. with this preamp to the Mono Block.

And, what is the best way, mechanically speaking, to do this... I realize just solder the wires in, but any caveats this newbee isn't aware of would be appreciated, in modifying something.

Please realize I am just starting out w/tube amps on a component level, and I have found existing 12VDC 1.5A in the circuit, :), or could stepdown the 25VDC 3.5A, through trial and error; I just would like to do it "correctly". I've already started to tinker, so hope to hear back prior to moving on with it anyway.

This little PCB preamp is currently powered by an external 12V 1/2 amp wall wart I had laying around. And works well with the amp, just want to start putting it all together. This PCB does not use tubes rather three 2SC945 transitors, (did this for Size more than anything). I want to be weary of size when I finally assemble it into a cab.

The sound is actually not bad, for the altered use, though I do get a bit of hum/noise, probably from the pickups, when used as a guitar input... (oh well :)... this is a learning endeavor... I deliberately did not buy a cookie cutter kit, to make it harder on myself for learning purposes. (BTW, the kit as intended is AMAZING, to my ears anyway... even w/cheap 4 ohm, speakers).


Thanks in advance.

-Craig

[4-CHANNEL]

Craig:
I think you want to mix transistor with tube in same circuit. It is possible to do so. 2sc945 is a silicon planner transistor, general purpose, use in small signal amplification is suitable, you can achieve the supply voltage from the power tube cathode, in olden B/W TV design, the tuner employed BFxxx is a pnp germanium transistor, by flipping the C-E leg, the supplied voltage became +, then got the voltage from cathode of the horizontal power tube. Another method you can use resistor and zener diode to low down the voltage from B+. SM-12 is a typical design of a tube amplifier, you can get a low voltage from the power tube cathode.