This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Tuesday, May 1, 2018

Darkglass Microtubes B3K

Gotten a few requests for this one and I finally got around to doing it. It's a bit of a hodge-podge–3 dual opamps, a hex inverter, and a JFET mu-amp array. Definitely not fitting this in a 1590B, but will fit nicely in a 1590BB with the pots board mounted. Info and schematic here.



16 comments:

  1. On the vero layout (left side) you used two further not defined red leds, on the left side I read 1N4148 diodes. Why? Which is the factory standard?

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    1. You could use either depending on your taste. I think the 'original' is probably 1n4148.

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    2. The original is 1N4148s. I think I mistook them for LEDs on the schematic initially, then when I went back through and double checked I realized they were 4148s, changed them on the pcb side, but forgot to on the perf.

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  2. i love this, finally some did it :D
    will you be doing B7K maybe?

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  3. I built it, I’m having issues with the 4049. On the tagboardeffects layout they used an unbuffered one. But all schematics say other wise. I Don’t have one on hand to test that theory out.

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  4. Hi. Do you think a potentiometer will work instead of the switch for the attack? Thanks

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  5. Verified with the components above. You might vant to socket the J201 and try other FETs, like 2N5457 for more round sound and less distortion. It isn't distorting much, at least for me. Very mild and musical, good for bass. If you want more distortion a BAT46 (in place of the two 1N4148) or another low low forward voltage schottky could be a good mod, but I did not try it. I think I will box this one as it is.

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    1. AD712 in the place of TL072 in the upper left corner makes it sound more hard. Slightly more distortion, more rock.

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    2. Thanks for verifying and for the notes. Good stuff!

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    3. One more thing... are you sure th upper 4148 goes to +9V? Not to blue line next to it coming from the leg 8 of the upper left dual OP-amp? This could explain why is there so little distortion. I compared your layout with this: http://tagboardeffects.blogspot.hu/2017/05/darkglass-microtubes-b3k.html

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    4. I am not sure. It sounds good as it is, but I really don't understand why is it going to +9V.

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    5. The schematic on FSB says it goes to +9V

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    6. In the end I have tried this circuit with the above mentioned BAT46 mods. As predicted, there is more distortion on tap, but can be tamed. I have found it more useful like that. Another note: C100K is really useful in this circuit. If you can not find reverse log pot, put a 240K res between the pins 1 and 3 of a linear 250K pot. It makes it a reverse log ~130k pot. Fits nice here.

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  6. Quick advice for those who etch their own boards with the toner transfer method: the extra through hole of the 220nf capacitor on the attack 3 switch is very close to the attack 2 rail so... watch out.

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    1. Good catch. Sorry about that! Fixed now.

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