Several years ago, I had a JMP 2204 circuit built for me by Mark Moser at Frugal amps. (Phenomenal guy and builder, BTW). I love the amp but am now smitten with the Express clone from Tonic Amps.
Now I'm wondering, just what would it take to convert a 2204 to an Express? I can provide gut shots soon if you'd like to see Mark's work. It isn't a faithful 2204. He called it an "Olympic style doping amp," but I have no clue what that means. Any thoughts?
Convert 2204 to Express???
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martin manning
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Re: Convert 2204 to Express???
Some time ago I built an Express (using a non-traditional layout), and then realized that there wasn't that much difference between it and a 2204, so I used the same basic chassis and modified the board layout to suit a 2204 circuit. I bought a new set of transformers and a choke (which the Express doesn't have). The differences are the Express' B+ is low, around 400V (JMP/Early JCM800 50W level), and the TW OT has a 6k6 primary impedance where the Marshall 2204 is around 3k5.
Re: Convert 2204 to Express???
Lol. In my case, he was reasonable. $1400 total cost and it's a beautiful amp.
Re: Convert 2204 to Express???
That's great to know. I may convert it in the future. Thank you!martin manning wrote: ↑Sat Oct 23, 2021 10:41 pm Some time ago I built an Express (using a non-traditional layout), and then realized that there wasn't that much difference between it and a 2204, so I used the same basic chassis and modified the board layout to suit a 2204 circuit. I bought a new set of transformers and a choke (which the Express doesn't have). The differences are the Express' B+ is low, around 400V (JMP/Early JCM800 50W level), and the TW OT has a 6k6 primary impedance where the Marshall 2204 is around 3k5.