About Me
I became interested in electronics, specifically tube amplifiers, about 10 years ago and began to teach myself what I never learned in school. An undergraduate degree in Mechanical Engineering and a number of post graduate classes in fluid dynamics and thermodynamics never gave me any sort of electrical or electronics background. I had one semester of circuits and one semester of digital design and that was the end of my formal training in electrical engineering.
My first real exercise into tube amplification came in the guise of a Fender Champ 5F1 clone that I built sometime in 2018.
I began to buy random valves through eBay and other sources when the prices seemed right. This got me motivated to begin looking for uses for the collection that I was building. There was a lot of hoopla surrounding single-ended tube designs so I went to peruse the internet and found an interesting paper by Claus Byrith that was written in partnership with Lundahl transformers. That outlined a design that I call the CB8. An 8 W, single-ended, EL34 amplifier with a 12AX7 input stage, a cathode follower input buffer and negative feedback. This was a large departure in terms of complexity to the simple, mono, Fender Champ design. But after the proper diligence, it all came together with Edcor iron, a nice walnut case from Hammond and panels from Front Panel Express. And to me it sounds amazing.
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I loved the sound of my new amplifier, but the volume levels seemed a bit low to me when driving my B&W CM1 speakers which don't have spectacular sensitivity. Lurking around the DIY Audio Projects site, I came across a post for a simple pre-amplifier design that works with a multitude of tubes, the venerable 4S. Not ready for another undertaking as large as the CB8, I started planning a build in early 2020. It came together using junk box parts and the result opened up the CB8 in ways I didn't think possible.
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Looking around for uses of random tubes I had on the shelf, I stumbled across a page for the Squirrel Monkey amplifier somewhat later in 2020. Since I had a 6AF11 collecting dust, I thought it would be fun to put one together, Also in the spirit of both education and "use stuff up" I decided to fabricate it using a tube rectifier instead of solid state components in the power supply. What a great little amplifier!
Then it was Covid, moving, promotion, and everything got put aside for a couple of years. Now, I have a lab set back up, and am diving back into this passion. I started out with the idea of building a tube preamplifier with a phono stage based on an uncommon tube, the TS-84, a tape loop, and tone controls. That then escalated to relay switching for the inputs, DC filament supply, selectable phono cartridge loading and ground lift circuits. All powered by an Arduino Nano Every. That project is still in development, and will be shared on this site, but in the meantime, I had a few other avenues that I travelled.
So look around and have fun!
