Sunday, 6 October 2019

PedalPCB FET City Drive



4 comments:

  1. This comment has been removed by the author.

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  2. Well, I built this and I am pretty sure it works. It sounds really good, except when drive is low: not much sustain and has some weird artifacts.
    Used audio probe and everything is fine until signal hits the left Mosfet (Q1 here but Q2 in pedalpcb schematic) which sounds as if badly biased.
    I am getting very different voltages in both Mosfets, and Q1 looks weird (and I can't see the reason why since they should be biased very similar...if I am not missing something...)

    Q1: S-0.0V; G-1.7V; D-8.9V
    Q2: S-0.1V; G-2.2V; D-4.6V

    I am going to keep troubleshooting and try to see why it is behaving like this.
    Anyway thanks for the layout, and I am pretty sure it is good and the mistake is on my part

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    Replies
    1. Yeah, Q1 looks wierd for sure. Those MOSFETs can be sensitive, have you tried another one?

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    2. Yeah, didn't made any difference - next up I think I am going to replace the 5k1 to Q1 Drain with a trimmer.

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