Hi, i'm just in the middle of building this but could you tell me the reason for the diode between the 18v and 1k8 resistor? I've looked at a few schematics for this circuit but none of them have this on.
It’s just a power protection diode. It’s tacked on for protection against reverse polarity etc. it doesn’t effect the sound of the circuit. It’s there for insurance. Anders usually adds a 1M pull down resistor too which helps eliminate unwanted switch pop.
Thanks for that. I've got it all soldered up apart from the 12k resistor between q1 and q2 as I don't have one, ive got a 10k and a 20k though. Could I use one of these instead or should I just get a 12k ordered?
Either would probably get it working but I my feeling is that everything matters. Especially on a smaller circuit. If you have another 1.8k, you could solder it to your 10k and get closer. Doesn’t look pretty but it works in a pinch.
This layout (like the original pedal) runs on the conventional negative-ground power supply. If you want to modify it to run on a positive-ground power supply, you would need to reverse the orientation of the electrolytic capacitors & D1, as well as using PNP transistors instead of NPN. Good luck!
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ReplyDeleteHi, i'm just in the middle of building this but could you tell me the reason for the diode between the 18v and 1k8 resistor? I've looked at a few schematics for this circuit but none of them have this on.
ReplyDeleteIt’s just a power protection diode. It’s tacked on for protection against reverse polarity etc. it doesn’t effect the sound of the circuit. It’s there for insurance. Anders usually adds a 1M pull down resistor too which helps eliminate unwanted switch pop.
ReplyDeleteThanks for that. I've got it all soldered up apart from the 12k resistor between q1 and q2 as I don't have one, ive got a 10k and a 20k though. Could I use one of these instead or should I just get a 12k ordered?
ReplyDeleteEither would probably get it working but I my feeling is that everything matters. Especially on a smaller circuit. If you have another 1.8k, you could solder it to your 10k and get closer. Doesn’t look pretty but it works in a pinch.
ReplyDeleteI've got a 10k and a 2k, I'll see if I can squeeze them both in thanks.
ReplyDeleteYou would just solder them end to end. So you have the two sets of color bars next to one another. --0-0-- like this. Then treat it as a single value.
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ReplyDeleteHello, I was wondering if this would work with negative polarity? thanks
ReplyDeleteThis layout (like the original pedal) runs on the conventional negative-ground power supply. If you want to modify it to run on a positive-ground power supply, you would need to reverse the orientation of the electrolytic capacitors & D1, as well as using PNP transistors instead of NPN. Good luck!
DeleteThank you so much!!!
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