JFET boost

Stompboxes circuits published in magazines, books or on DIY electronics websites.

JFET boost

Postby Nocentelli » 08 Oct 2017, 20:17

A simple boost/preamp circuit I put together recently. The JFET starts to clip in a pleasingly smooth manner if you really dig in so the gain control allows you to set how hard you need to play to make this happen. The simple active two band EQ gives a nice range of tones for not many parts.

FETBoost_schem_nocentelli.bmp
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mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.

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Re: JFET boost

Postby roseblood11 » 09 Oct 2017, 16:38

Nice. Do you see an advantage of this circuit over the Boss FA-1? The parts count is similar.
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Re: JFET boost

Postby Nocentelli » 09 Oct 2017, 18:14

I think the JFET gives a certain je ne sais quoi that an op amp booster doesn't, i.e. mainly a little bit of distortion/compression on the edge of the notes when you hit the guitar hard. Apart from that, I had one single decent spec J201 left in my stash of through-holes that I wanted to make into something useful :lol:

Since posting the schematic, I have attempted to design a small and efficient veroboard layout and have (re)discovered that single op amps are terrible for efficient use of space. I've done another schematic for a transistor-based baxandall stage, which should be much easier to lay out nice and small. I'll post the new schem when I'm happy it works properly and sounds as good as the one above.
mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.

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Re: JFET boost

Postby Nocentelli » 14 Oct 2017, 12:08

FETBaxBJT_nocentelli.bmp
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mmolteratx wrote:absolutely zero commercial use allowed. If I find anyone selling these, I'll fly to your house and kick you in the nads. And you may or may not find yourself in trouble.

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287m (14 Oct 2017, 14:56), dv8r601 (17 Oct 2017, 03:11), Intripped (14 Oct 2017, 13:50), Manfred (14 Oct 2017, 16:08), mirosol (14 Oct 2017, 14:25)
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