Chuck D. Bones
Circuit Wizard
I've had it in my mind to build a Range Master style boost for a while, here's the final result. I borrowed elements from the LovePedal Church of Tone and the Catlinbread Naga Viper. It started out with a single NPN Ge transistor gain stage. I did not like the way it loaded the pickups, Humbuckers or single coil. It lacked sparkle. I tried putting a buffered bypass pedal (DS-1) in front of it and the sound opened right up. So I added a FET buffer at the input. What I ended up with sort of resembles an EQD Crimson drive, only with the CoT's variable gain/bias control and the Viper's variable treble boost. Since the JFET was not in the original vero layout, I had to cram it in wherever it would fit. The 1M anti-pop resistor ended up on the stomp switch. Anyway, here it is in its final form. How about that aqua blue LED?
Here it is pre-wired, just before the board went in. I have quite a few Mammoth pots left in my stash! The Tayda boxes are powder coated on the inside as well. I made sure the pots and jacks all have tooth washers to bite thru the paint.
I had to alter the outboard wiring a little bit when I added the buffer. Not shown: I insulate the board by wrapping an old business card around it.
The CLIP switch disconnects the diodes for clean boost. The TONE pot rolls back the bass when turned clockwise. The GAIN pot varies the gain from 5dB to 36dB. Because the GAIN pot also varies the bias, it makes the scratchy noise when turned. With CLIP off, this pedal is capable of over 6Vp-p output. I added C8 to smooth out the distortion when CLIP is on. Because the diode clipping is asymmetric, I added C6 and R8 to remove any residual DC in the output waveform. A variety of JFETs and Ge transistors will work in this circuit. For the gain stage, I used a Russian MP38A. Any low-to-medium gain Germanium transistor will work. The one I used has hFE = 65.
Here it is pre-wired, just before the board went in. I have quite a few Mammoth pots left in my stash! The Tayda boxes are powder coated on the inside as well. I made sure the pots and jacks all have tooth washers to bite thru the paint.
I had to alter the outboard wiring a little bit when I added the buffer. Not shown: I insulate the board by wrapping an old business card around it.
The CLIP switch disconnects the diodes for clean boost. The TONE pot rolls back the bass when turned clockwise. The GAIN pot varies the gain from 5dB to 36dB. Because the GAIN pot also varies the bias, it makes the scratchy noise when turned. With CLIP off, this pedal is capable of over 6Vp-p output. I added C8 to smooth out the distortion when CLIP is on. Because the diode clipping is asymmetric, I added C6 and R8 to remove any residual DC in the output waveform. A variety of JFETs and Ge transistors will work in this circuit. For the gain stage, I used a Russian MP38A. Any low-to-medium gain Germanium transistor will work. The one I used has hFE = 65.
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