Hoffman Amplifiers Tube Amplifier Forum
Forum and Web site Stuff => Introduce Yourself => Topic started by: stephenjbassett on November 14, 2021, 01:37:24 pm
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Hi folks,
Steve B from Austin, TX. Purdue EE, spent my career building and managing computer chips with billions of digital and analog transistors, but enjoying tinkering with my amps that have fewer ~transistors (tubes) than I have fingers. I've been building my own guitars, fiddles and mandolins and speaker cabinets since highschool but have time now to tinker with my amps. I recently turned a perfectly good 15W 6V6 Fender Super Champ XD into a couple of used transformers and scavenged components while "upgrading" it to switched fixed/cathode bias and adding a rheostat in the power supply chain to emulate a tube rectifier. It all worked, though the tone variation wasn't worth the effort. During that mod I zapped the 5V digital and 12V analog supplies, which weren't designed very well to begin with. After the bias wire solder joint let go, I fried something else, so I'm rebuilding it from scratch into the "SuperChump SB" to remind myself that I should have started from scratch to begin with.
This new head design will use a switchable solid state rectifier with a 5AR4 tube, a two-channel preamp (one opamp-based solid state using my own regulated +/-12V supply, the other an EF86), and a typical cathode-biased, pp 6V6 power amp.
Between Rob Robinette's pages and this site, there's plenty of advice and sharing of what works and, equally important, what doesn't work.
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Welcome to the Hoffman Amps forum
There are many different boards on this forum for different topics.
The Tube Amp Building - Tweaks - Repairs board is where you can post amp questions.
That board is listed here.
https://el34world.com/Forum/index.php?board=13.0
Thanks,
Doug Hoffman