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Post by flateric on May 12, 2011 10:40:13 GMT -5
I need some help to design a 3-band parametric bass pre-amp pedal, can't find any schematics anywhere.
Boss used to make one : PQ-3B, with stacked rotary pots for freq and Q: low, mids and highs.
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Post by andy on May 12, 2011 11:18:20 GMT -5
Here's one for the PQ-4, the guitar version. I don't know how much use it is, but I guess it just has some different component values to make it a bass or guitar version. synthdiy.com/files/2007/boss_pq-4.png |
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Post by flateric on May 13, 2011 5:50:47 GMT -5
Whoa! Thats a bit complex for me. Lets try and simplify;
How about a mosfet-boost-based circuit to act as a pre-amp, then add in a parametric mid control? It would need to have:
i) master volume knob,
ii) mid boost/cut knob
iii) freq adjust knob
iv) if possible, freq width to allow for either small or wider range of mid freqs to be cut or boosted.
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Post by andy on May 13, 2011 8:54:55 GMT -5
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Post by flateric on May 13, 2011 10:10:14 GMT -5
I'm a big fan of the mosfet boosts, made a dozen in my time and given them to friends and bandmembers, put them in series with tubescreamers in the same enclosures, they always work well. I'll check out that geofex parametric and see what can be hatched. Cheers for the input!
Anyone care to advise how I turn the Bootstrapped twin T circuit with variable Q into a PCB layout I can etch & build?
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Post by ashcatlt on May 13, 2011 10:27:03 GMT -5
EagleCAD or DIY Layout Creator?
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Post by flateric on May 13, 2011 11:26:20 GMT -5
DIY would be great!
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Post by ashcatlt on May 13, 2011 12:22:38 GMT -5
I've never used either one. I think (?) Eagle will take a schematic and make a PCB layout automatically. DIYLC I think makes you draw the traces yourself. |
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Post by flateric on May 13, 2011 16:26:28 GMT -5
diylc ive used before but something scribbled down on an envelope would suit me fine  |
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Post by ashcatlt on May 13, 2011 19:37:16 GMT -5
Umm... Anyone care to advise how I turn the Bootstrapped twin T circuit with variable Q into a PCB layout I can etch & build? I mean I suppose you could use the back of an envelope... Do you have 5spice or something similar? Draw up the schematic and mess with values till it does what you want. Then use DIYLC to lay out the PCB and have fun with chemicals which I can't keep in my house because of the insane short people. Edit - Or go over by DIYSB and poke around. I'd be willing to bet somebody's got a PCB layout for exactly what you're looking for. Course, you don't need the link, since I see you over there using your "real" name on occasion. Edit again - Wait! Breadboard between the spice and LC step to make sure that what looks right actually sounds right. |
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Post by flateric on May 14, 2011 3:09:05 GMT -5
never played with 5spice before, must investigate further...
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