Yamaha GX VCF (untested layout)

vladosh · Posted: Mon Apr 11, 2016 1:12 am Post subject: Yamaha GX VCF (untested layout)

this is pcb for MOTM Yamaha GX VCF , the schematics are shared on the MOTM page , it's still untested layout using BCM847 and BCM857 pairs instead of the variety of transistor chips in the original MOTM schematic ,pcb size is 100x100mm ,if for some reason i need to remove the layout just notify me ,SSM is written on the pcb only for orientation it is actually a BCM857

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vladosh · Posted: Thu Dec 14, 2017 9:07 am Post subject:

here is a working layout for the Yamaha GX ,just finished and found some errors ,now it's fixed ,i used J201 for the FET ,it is sourse - gate - drain > placement on the diagram

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LFLab · Posted: Thu Dec 14, 2017 9:20 am Post subject:

Nice!

So you used an adapter for the BCM's (you can only get them in SMT, right?)?

Link to the schematic? this can probably shrunk quite a bit if going to SMT for everything, interesting!

Found it: http://synthtech.com/docs/MOTM-485_manual.pdf

vladosh · Posted: Thu Dec 14, 2017 9:55 am Post subject:

its range is kind of narrow ,at least on mine ,but the resonance is why i want to keep it

vladosh · Posted: Thu Dec 14, 2017 9:55 am Post subject:

BCM is only SMD ,i used adapters from 258's pdf here on forum

gabbagabi · Posted: Mon Dec 18, 2017 5:59 am Post subject:

lot of work!

i really like how u draw the resistors, i will do it from now on the same way.

btw i never heard about that filter, thx for bringing it in

vladosh · Posted: Tue Dec 19, 2017 7:34 am Post subject:

thanks ,it's not that good the layout as there is some noise in the feedback jumper ,maybe it's best to build the MOTM pcb ,but if anyone tries to build this here is layout with room for that 1.2K resistor in the feedback jumper

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