Help needed for guitar preamp/power amp schematic.

VpV

Member
2010-09-22 2:34 pm
Hello. I registered here in order to ask for little assistance regarding a schematic I’d like to build. My questions might seem funny, but that’s because I have little experience with electronics - I’ve built few simpler circuits, by strictly following the schematics (which were quite clear). This time however, the “project” is bigger, and I also have trouble understanding something in it.

This is 100 watt guitar power amp which I’m aiming at – http://sound.westhost.com/project27.htm

First I want to build the pre-amplifier, and later make the power amp. So for now I’ll ask only questions regarding the preamp:
Can you tell me which of the capacitors are electrolytes, and their correct position (polarity) in the circuit? I’m used at seeing schematics that clearly mark the caps, but this particular one doesn’t seem to follow that rule so I’m a bit confused as to what types of caps I should get.

One more thing. As I see it, the preamp is supposed to run at 15v which is lowered from 35 by the power supply section. I already have 12v dc transformers for such types of electronics, so I want to know if I can simply bypass that power supply section and feed the circuit with 12v dc (500ma)? That’s because I don’t have 35v transformer, and I won’t get it until I really need it – for the power amp.

My current idea is to make only the preamp, and use it to record audio on the pc. And later on make everything and put it together. Will my grand plan for world domination… cough. I mean will my plan for audio recording work :devily: ?

Any help will be greatly appreciated.
 
Hi VpV,

Capacitors are shown on a schematic as two parallel lines, electro's are shown with the positive side as a rectangle box (sometimes with a + beside it) The electrolytic capacitor itself has a stripe on the negative side with - (minus) printed on.
Because the circuit that you are planning to build has op-amps, you will need a + & - 15V DC supply
Hope this helps
 

willy

Member
2002-10-05 4:32 am
usa
Guitar amp

Yes you can use a seperate power supply for preamp. I built the original, now project 27B months ago. It's easier than the updated version, fewer parts for a beginner and sounds great. Mine is still in use. Guitars are different, I had to experiment with different capacitor types and sizes to get the sound I wanted from my rig. Have fun.