New concept amp......

For those building and repairing amps on their own. Learna and share ideas.

New concept amp......

Postby Jack Hester on Tue Jan 14, 2014 12:19 am

Over on the Hoffman Amp Forum, one of the members (Tubenit) has come up with another really good amp design. As he is an active performer, his amps are designed to his tastes. From what I can tell, they begin life as something with a Marshall sound, but he likes a Dumble sort of Overdrive. And, he tweaks everything, constantly.

His latest is called the Tweed BluezMeister 5879. He likes to use a MOSFET IRF820 as a Cathode Follower after his 5879, in the Overdrive of his amp. As I tend to not use solid state components in the signal path, I decided to do a concept off of his design (with his blessing). I put a triode in as the CF, and rather than a Long-Tailed Pair Phase Inverter, I chose to use a Cathodyne PI. That way, I can use a 12DW7, where Section 1 (equivalent to 12AX7) is used as the PI, and Section 2 (equivalent to 12AU7) is used as the CF.

I've started on the mod (drawing, only) Christmas week, and just completed the last revision. I just found out that I can't upload a PDF file here, so I'm posting the link to the discussion on this design: ... #msg161480

I'm hoping to get a board and chassis started in a couple weeks. I don't know how it will compare with his design, with the difference in CF and PI. He usually posts a sound clip of his work, but hasn't done one for this design, yet.

Take a look, and check for errors, as well as comments for improvements. Have a good one.

"We sleep safe in our beds
because rough men stand ready in the night
to visit violence on those who would do us harm."

---George Orwell
Jack Hester
Posts: 189
Joined: Sun Sep 12, 2010 11:12 pm
Location: Roxboro, NC

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