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, March 20, 2018

Baja VH4

Another drive circuit from Bajaman. He's been on a tear lately! In his words...

Here is my latest build based on the frequency response characteristics of the Diezel VH4 tube head channels 3 and 4, but scaled down into a 9v dc pedal friendly format... I got a chance to try using it on Neil Young's "Keep on Rockin' in the Free World" and needless to say it sounded awesome on very low gain setting Channel 3 - just the right amount of searing crunch and in my view one of my best pedals to date!

It will fit in either a 125B with top mounted jacks, or a 1590B with side jacks. If you go 1590B, you'll either have to offboard the pots or use long leg pcb-mount pots and populate them on the component side. I've added extra pads for the JFETs so you can use either DGS or GSD pinout transistors. Schematic can be found here.




5 comments:

  1. Great! Thank you so much for considerung my request! :)

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  2. Any link on recorded sample via Baja's schematics?

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    Replies
    1. here you go, thanks to Temol
      https://soundcloud.com/user-275816837/preamps-from-bajaman

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  3. Nice layout on Baja VH4. Not so easy. I'm working hard on Baja MDR, and it's not done :)
    One remark/question about your layout: are your sure about the orientation of Q3? Drain and source seem to be inverted in the 2SK117 datasheet (http://pdf.datasheetcatalog.com/datasheet/toshiba/1025.pdf). But this datasheet is not the clearest one of the web ;).

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  4. Verified!
    I finished this circuit yesterday with all the same components except the mosfet.
    The only ones that were more similar to the 2SK117 were the 2SK30A, so I noticed that the pinout is not good, for the 2SK30A the position in the drawing is correct, but if they put the 2SK117 have to reverse them.
    Regarding the sound is a medium overdrive, but produces a kind of noise the chips to pop over the sound, a little irritating I did not like, the components I used are all top quality, it could be maybe the mosfet I'm using.

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