Category: Amplifiers

When Frankie disassembled a Hammond M103 organ he picked up from the side of the road, I ended up with a huge pile of parts. Lucky me, an AO-67 amplifier and two Rola 12″ alnico speakers fell in my lap! By the look of the completely dry-rotted, twisted and shorted out 2-wire power cord and the incredible depth of dust on this thing I could tell it had been sitting for a bare minimum of 15 years. One of the speakers needed a little cone repair and all of the electrolytics were dried out.

This started out as someone on TDPRI asking for some enlightenment on what the various components do in a 5E3… before I realized it I had described nearly every component! Here it has been consolidated and reordered, along with a copy of the Weber 5E3 Deluxe layout that was used as reference.

I had been wanting to try an octal preamp for a while, so I figured 2011 would be a good time to build one. This amp has gone through about a dozen revisions with tons of experimentation along the way. After 2 years without major modification, I ditched the cascode and moonlight tone stack on Channel 2 in favor of a two-stage design. After a ton of trial and error, attempts at all sorts of interesting preamps, the current “final” version squeezes roughly 50 watts into a chassis smaller than your typical 18-watter. It was quite a challenge, and it’s...

Building an all-tube-powered 5.1 channel surround sound home theater system is probably the most ambitious project I have attempted. My goal is to build a surround sound home theater system using all tube amps, and to do it without bankrupting myself in the process. To pull this off I had to set a few guidelines that would keep this project under control: