- Feb 19, 2013
- Reaction score
- Las Vegas, NV
After much delay... my 100W 16ohm M2 build is done. This was built in a salvaged case from an old car audio amp, which has a massive heat sink on top and sides. The front panel is 1/4" black acrylic, laser cut and engraved on a Glowforge laser cutter. I "experimented" with filling in the etched lines on the front with paint, which sort of didn't work well but I decided I like it looking a bit distressed anyway. I couldn't do the back panel in acrylic because I didn't have jacks that work in a 1/4" thick panel, and thin acrylic is too flexible.
Schematic follows the M2 50W version with all the ratings doubled - except a couple resistors R6 and R7 which according to my ltspice sim only dissipate about 4W and 8W each even with a 170W input like a superlead. So those are just the usual 25W parts. R1 is two 100W parts in parallel. I used Carling mini-toggles for the stages as these never see more than about 2.5A current, so the 5A mini toggle is ok. Bypass and cab switch are full size 10A rated toggles. Inductor is a 15ga part from partsexpress. Internal wiring is all 18ga. The cab switch is mostly for convenience at home, where I usually have two different cabs in the music room - so I can keep them both hooked up. I originally was going to have a dual input switch but decided to use it for bypass instead. In hindsight it's so transparent I should have just not bothered with the bypass and done the input switch, oh well next time.
I don't have any gut shots but let's just say it's not my proudest soldering job. I felt like a real beginner getting good joints on those 100w Arcol resistors, and that's with a fairly high-end soldering station. Ended up using an absurdly large chisel tip and plenty of extra liquid flux.
Sound quality is amazing, many thanks to @JohnH for this great design!
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WOW! I'm quite happy to say that sure puts my builds to shame! Great to see folks taking this design and running with it, to the next levels! And yeah, they sure do work great, don't they? Please let us know about heat, when cranked for long periods of time? Is there a fan included?