4 March 2013

Building a high gain amplifier part 2: The poweramp

Hey guys. I haven't been keeping up with this as well as I had hoped to but life gets in the way you know?

Today i'll give a brief overview of the poweramp. If you are using PCBs from C3amps or SmashGuitars this is all silkscreened so is an absolute breeze.

As usual I always start with the smallest components as it makes it far easier to keep things flush against the board as you build it up.

The smallest parts on the poweramp PCB are the balancing resistors for the filter caps which make sure that the caps see an even voltage. They also perform an additional function of bleeding away any voltage once the amp is powered off making it safer to work on which is a nice bonus. It does take a few minutes though so always check the voltages before working on the amp.

From here we move onto the diodes that form the rectifier for the AC input and also the bias supply. These have a polarity so make sure to check the circuit and silkscreen matches up with the way you insert them.

Also notice in this picture there is a jumper. This is one of the capacitor legs that I saved whilst doing the preamp. 

Next I install the axial capacitors for the bias and filtering. Again these are polarised so be mindful of this when soldering.

And finally moving onto the main filter caps. The F&T caps are truly fantastic for this application and they are what I will be using.

And that is all! Nice and simple just so long as you keep track of the polarities. The next post that I do will actually be wiring the preamp into the amp as I got my chassis predrilled and prepped from C3amps to save some time and work. I'm not going to say when the post will be up as everytime I do that something gets in the way so just keep checking back!