Champ Amp, My First Amp

Submitted by imre on Fri, 10/20/2006 - 02:00.
in

This was my first tube amp experiment. It is based on a Fender Champ from the 50's. The Champ was designed to be a cheap practice amp. It features all-tube construction, about 5 Watts of power and tone control!


The tone control is rather lousy. The signal path is as follows: The first stage of the 12AX7 is used as a preamp driving the passive tone filter, the second stage is used as the output tube driver which feeds into the 6V6 output tube. The tone control is a passive bandpass filter and it doesn't work very well. Technically, the amp was based on the Fender Princeton Model 5F2, but this just included a few upgrades over the classic Champ amplifier - two inputs (so you can practice with a buddy), the tone control and an inductor in the power supply filter. You can find the schematics below. The main upgrade I performed was the addition of a magic eye guitar signal detector. The magic eye dances while you play the guitar. I used a EM80/6BR5 type described on my Magic Eye page.

Here is the schematic:

Click here to check out all the construction pictures in the gallery.

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