SOLVED Simple Jfet Buffer - Mega-Dumbass Wiring Question...

[Caldo71]

Okay so it IS a very simple circuit...but here is where I am a dumbass:

I'm building this as a separate circuit, in a separate enclosure...it's not permanently piggybacking onto another pedal.

SO, I see the pads for power (+) and (-), and one pad each for input/output. But what about the ground leads on the input/output jacks? Do I ground them to the (-) DC pad? To the enclosure? Leave 'em out entirely? See attached diagram.

I've seen other stomp box kit PCBs (not pedalpcb—other brands) where the ground wire is omitted from the output jack if I remember correctly...and although it gives me the willies I guess I've been led to understand that technically you're not supposed to need it? But I'm not sure if I've ever seen the ground wire omitted from both jacks.

Somebody tell me what the smart move it here...

 

[jimilee]

As long as the enclosure is a normal aluminum one and you’re using metal jacks, you really only need a ground wire on the input jack. The enclosure will do the rest of the work.

 

[Caldo71]

As long as the enclosure is a normal aluminum one and you’re using metal jacks, you really only need a ground wire on the input jack. The enclosure will do the rest of the work.

...and that input jack ground wire would connect to ground...where...?...

 

[Laundryroom David]

Okay so it IS a very simple circuit...but here is where I am a dumbass:

I'm building this as a separate circuit, in a separate enclosure...it's not permanently piggybacking onto another pedal.

SO, I see the pads for power (+) and (-), and one pad each for input/output. But what about the ground leads on the input/output jacks? Do I ground them to the (-) DC pad? To the enclosure? Leave 'em out entirely? See attached diagram.

I've seen other stomp box kit PCBs (not pedalpcb—other brands) where the ground wire is omitted from the output jack if I remember correctly...and although it gives me the willies I guess I've been led to understand that technically you're not supposed to need it? But I'm not sure if I've ever seen the ground wire omitted from both jacks.

Somebody tell me what the smart move it here...

View attachment 47137

I’d connect the input sleeve to the neg lug of the dc jack and leave the sleeve of the output un connected

 

[Laundryroom David]

Some of Aionfx’s older build docs have a good explanation of star grounding that you might find handy.

Edited to add link: https://aionfx.com/app/files/docs/procyon_legacy_documentation.pdf

 

[Caldo71]

Some of Aionfx’s older build docs have a good explanation of star grounding that you might find handy.

Edited to add link: https://aionfx.com/app/files/docs/procyon_legacy_documentation.pdf

Aion was actually the specific PCB maker I was referring to earlier when I'd said I'd seen others' builds that omit the ground on the output.

Thanks for the educational link! His article on sourcing good parts and the method behind it was super-helpful to me early on.

 

[yazooligan]

So where does one put this buffer normally? Before or after a different circuit?

 

[BuddytheReow]

So where does one put this buffer normally? Before or after a different circuit?

Both. Buffers, in general, are used to keep the signal integrity over a long distance (think 30ft guitar cable). If a circuit likes the buffer you won’t notice anything. Other circuits, such as a fuzz face, don’t mix with a buffer before it. You’ll need to experiment to find what works with your rig. Buffers are usually done either the beginning of the pedal chain or right at the end into your amp.

 

[PJS]

Personally I would add a ground wire to both audio jacks. Connection to the ground on the DC jack is a good spot. If you leave one ungrounded it will ground through the case as long as there is a good mechanical connection of both jacks to the case. As soon as one of those nuts loosens off then you will get all kinds of hum. I have seen that happen on pedals that are left permanently attached on a pedalboard, so not disconnecting/reconnecting it all the time doesn't seem to be a guarantee it won't happen.