Monday, 28 April 2014

The Princeton Champ

I decided to treat myself to a valve amplifier kit, my home made valve amp is fine but is based on a 1960's hifi amplifier and really should have it's electrolytic capacitors replaced before it goes bang! So partly  I wanted something brand new and reliable and also fancied an American voiced amp with a 6V6 tube in it with that nice overdriven sound that could fit into almost any situation rather than EL84s  So I went for a 4 watt Champ clone from amp maker.   
It all came packed so neatly that I thought for a moment he'd forgotten the valves! The instructions are on line and easy to follow, it was really nice to build something that was guaranteed to work so I could focus on making a neat job of it. I t felt a bit like a busman's holiday but was nice to be building something I could keep bcz though I'm an optical assembly technician now I've been a panel wireman for about 40 years. I received it on Thursday and had it working by Sunday. How loud is 4 watts supposed to be? This thing was ear spilling before it started to overdrive! Good in a way bcz i want to use it in church!  So I added a standby switch too to extend the valve life.I plonked it upside down into an old solid state Behringer amp cab I had kept for such a project, which happened to have an appropriate Jensen speaker. I have to admit  wasn't so keen on the tone, it just sounded to warm and loose with my humbucker equipped guitars ,I could see that a Tele or Strat would be great but I have enough guitars already! I added the tone circuit and instantly loved it! One end of the tone control is mellow and jazzy and the other bright and twangy, but some how the in between sound works better for me. Maybe it's the cathode resistor bypass cap I had to add to make up for the lossy tone controls. This converts it from a Champ to a Princeton. Also I added a negative feedback defeat switch which boosts the volume but cuts the midrange. I didn't want to commit to it and drill a hole in the wood panel as I didn't want to over clutter it or change the internal wiring so wired it outside the chassis but intercepting the connection at the 4 ohm tap of the output transformer and fitted the switch in one of the side infill panels.