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Hi folks
Here is an updated version of my Baja SLO overdrive pedal - although the original design works very well, i wanted to get a bit closer to the individual gain stage's frequency and phase response characteristics and the only way I could see to do this, was to use four gain stages (not two as in the original BAJA SLO) matched to the actual four gain stage amplifier schematic
cheers
bajaman
finished mine today. Comes with a BM style tone control borrowed of the BSIAB II project. Made the low pass filter after the tc of the BSIAB switchable (that's the toggle switch). Love it. Simpler controls and yet pretty close to my Wampler triple wreck clone - though it sounds a bit raspier, which I like.
Its just this design plus an added big muff style tone control with the BSIAB values (http://www.generalguitargadgets.com/pdf ... ab2_sc.pdf) and the low pass filters of the BSIAB design switchable. Since this tone control "eats" some volume I added a simple ehx lpb-1 after the tone control. Since this design has a lot of output I decided to to put the volume control before the tone control to not overdrive the transistor and hence get some nasty added distortion. Sounds complicated but is really simple in reality. I took this an redesigned the PCB to my taste: http://effectslayouts.blogspot.de/2017/ ... stack.html
so, because your nick is Head, you forced yourself to use chicken head knob too?
To be super German here (which means no sense of humor ): It did use chicken head knobs because a) I got them cheap from eBay and they are made for split shaft type pots which I used here and b) chicken head knobs somehow always evoke the impression of amps to me.
287m wrote:
or where the best position to experiment?
Between clipping diodes and output buffer. Don't forget to decouple.
If any volume drop occurs, you can replace output buffer with a power booster.
Or add another gain stage to look like this: ->[clipping diodes]->[buffer/amplifier]->[tonestack]->[output buffer/amplifier]->[volume knob]
I revisited this pedal over the Christmas break and decided to add a tone stack on the output - I did change a few capacitor and resistor values, but essentially the circuit remains basically the same as the MkII version but with tone controls.
I used three small presets for the tone controls and built the tone stack on a small section of stripboard. I then attached it with double sided 3M insulating foam tape to the underside of the top of the enclosure and drilled three small holes in the base to allow adjustment of the three controls with a small flat blade screwdriver. I quickly found the "sweet spot" and once set, I felt that no further adjustment was necessary. Very pleased with this design and modification - here is the schematic - Happy New Year
bajaman
): It did use chicken head knobs because a) I got them cheap from eBay and they are made for split shaft type pots which I used here and b) chicken head knobs somehow always evoke the impression of amps to me.
