The B K Butler Tube Driver has been used by several of Rock Guitar’s greats – David Gilmour and Eric Johnson to name just two. There are many schematics out there as well as a wealth of PCB projects. I’ve looked to compile the best and most reliable for this post. If you’re wondering how these things sound here’s a demo for you:
Firstly a gut shot of an original unit from around the ’79-80 “Garage” (He originally made them in his garage!) period:
And a hand drawn schematic along with notes:
You could build that one if you fancy, however, bajaman took apart a reissue B K Butler Tube Driver and posted up his own project which is verified and working, and sounds great to boot – it also includes an interesting “Bias” mod which allows you alter the voltages seen on the tube’s grid which will alter the character of the clipping:
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| B K Butler BAJAman project schematic |
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| PCB Layout |
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| PCB Top Layer |
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| PCB Bottom Layer |
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| Tube Bias mod layout |
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| Footswitch wiring key |
And here’s the freestompboxes.org thread: http://www.freestompboxes.org/viewtopic.php?f=13&t=1171
