Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: plexi50 on September 19, 2010, 10:56:47 pm
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Another odd idea has come to the surface. Question:
Would adding a pair of clipping diodes to a 2203 clone preamp stage produce a bit more distortion?
I was thinking of adding a pair of 4148's and using a switch to bring them in and out if desired
I am contemplating this because my 100 watt amp sort of needs to be cranked to get the type of breakup i like at times
If this worked then i would not have to blast the universe to get the desired breakup at lower volume levels
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I suppose technically it would, but would this be superior to using a potentially more interesting overdrive pedal in the usual manner?
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You could certainly try it cheap enough. May not produce quite the flavor you're looking for; clipping is usually characterized as "harsh" and "abrupt" in terms of the level at which it kicks in.
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I have some great pedals and had thought about instaling the guts of one of them to the front panel and wiring it up. But i just cant do it. I love my pedals and they need to stay where there at. Sometimes i get tired of hooking up and bending over to make the adjustments. I have been looking at the 2100,2500,4100 preamp schematic clipping sections of those amps. Im not quite sure all together how i would do this to a 2203 clone
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The Carvin Vintage 50 series (Nomad, Belair, V50 head), MTS series, and Valvemaster series all use diode clipping in their dirt channels. The Vintage dirt channel is a muddy mess, while the MTS is tighter, but very compressed (it has an extra gain stage). I haven't heard a Valvemaster to compare. You might start with the Vintage series and tweak from there since its dirt channel is kind of similar to the 2203 (if you close one eye and squint with the other).
Carvin Vintage 50 (http://www.carvinmuseum.com/pdf/amps/112%20Nomad%20212%20Bel%20Air%20REV-E1.pdf)
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There's a Marshall diode clipping circuit that bnwitt liked IRRC. This may be the right preamp:
http://www.schematicheaven.com/marshallamps/25aniv_silverjubilee_25_50w_2550.pdf
I'm going to try a "variable compliance" clipping circuit in my next build just for fun. Schematic attached. Got lots of ideas from here:
http://www.muzique.com/lab/sat.htm
Cheers,
Chip
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Well i did what i said i would not do. Thats normal for me. I installed my Monte Allums BD2 H20 PS+ circuit board and pots to the chassis of my amp this afternoon. Started at 3:00 PM and finished wiring it up at 8:00 PM / Input jack sheilded cable to input of BD2 and out to plexi channel tube stage. I took my time doing this and for once i did not have to go tracking down an error. It sounds great and gives me the variable clipping i was after. Actually just a pedal wired in permanently to the input. Has true bypass so there is no volume drop. I think it turned out better than what i had envisioned
http://s356.photobucket.com/albums/oo5/plexijtm45/?action=view¤t=BD2MAOP1.mp4
http://s356.photobucket.com/albums/oo5/plexijtm45/?action=view¤t=BD2H20BSP2.mp4