Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Misc Schematics and Layouts => Topic started by: firemedic on September 28, 2010, 10:23:37 pm
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It took a long time but the schematic is done.
To recap, this is my first build. It started as a 40W 5E3 but since I had extra chassis room, (a 50W Laney AOR with problems) I went straight for a 5E9 Tremolux, 3 pa tubes. The 4th became a 2 stage reverb. This project has taken months of troubleshooting and tweaking & I realized I better button it up or I'd never just sit & play guitar again. The power tubes are actually a pair of those Tung-Sol "KT66" tubes which most techs consider to be repackaged 6L6GCs. Any thoughts on those would be appreciated, but they sound great. With a 12AU7 preamp tube it sounds incredibly clean.
I'm already thinking of more tweaks but this is it for now. The UAH stands for Ugly As Hell, which is putting it mildly, and 17B is a tribute to the fire station & shift where all the work was done.
PS extra thanks to tubenit, mrr3000gt, and lots of others on this forum whose hints & suggestions were absolutely indispensable.
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I couldn't resist JUST ONE MORE tweaking session, so I heated up the idle current to 56ma and increased the signal voltage before the reverb signal splits off, also put some mids back in the reverb. I might need to play Miserlou someday. I also dialed back the bright switch from 120p to 68p since it was kind of harsh. I'm hoping that changing the reverb return cathode bypass cap back to the (original to tubenit's) 10mFd, from 25mFd, will cut out a little of the OT 60Hz.
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Ooops I posted that last one too soon. I also returned the post PA coupling cap to the AB763 .047mFd, the .1 made it pretty muddy at high volume. It sings like a bird. Now I just have to learn how to play guitar. I may also try my miked acoustic guitar & even banjo, see how that sounds. Meanwhile I'll be keeping a nervous eye on my power tubes since I've never biased that high before.