DIY buffered junction box no signal pass.

A

_aj666

Member
Hey everyone, recently got some simple jfet buffers to get my junction box finished so I can finally wire up my board.

I've been following the one that vertex pedals made, but with the pedalpcb buffers. I got it all wired up, and no signal passes and I just get a static feedback.

Pretty sure I have all my ins/outs wired correctly, as well as power. If anyone can take a look and tell me how to proceed that'd be awesome! Thanks

IMG_5400.jpeg IMG_5398.jpeg 4 Cable (4CM) Method + Wet_Dry Tri Buffer.png
 
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Is there a ground wire connecting your upper two buffer PCBs together?

I see a black wire from the DC jack to one of the upper PCBs, and I see a black wire from the lower PCB to one of the upper PCBs, but I can't say for sure there is a wire connecting the grounds of the two upper PCBs together.

(See purple arrow)
1751072180832.png
 
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Robert said:
Is there a ground wire connecting your upper two buffer PCBs together?

I see a black wire from the DC jack to one of the upper PCBs, and I see a black wire from the lower PCB to one of the upper PCBs, but I can't say for sure there is a wire connecting the grounds of the two upper PCBs together.

(See purple arrow)
View attachment 98043
Click to expand...
Yes I have them all connected as they should be, everything's soldered up and under the electrical tape. Took a shot of under the buffers as well for you.
IMG_5414.jpeg IMG_5415.jpeg
 
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I think the grounding scheme might be intentional to avoid ground loops... whether or not it's achieving it's goal I can't say.

Since the jack grounds aren't all connected together (by wire nor the enclosure) they're depending on what is plugged into them to complete some of the ground paths.

If you have some clip leads you can temporarily connect all of the sleeve lugs (with green wires) together so they have one solid continuous connection and see if that helps.
 
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Robert said:
I think the grounding scheme might be intentional to avoid ground loops... whether or not it's achieving it's goal I can't say.

Since the jack grounds aren't all connected together (by wire nor the enclosure) they're depending on what is plugged into them to complete some of the ground paths.

If you have some clip leads you can temporarily connect all of the sleeve lugs (with green wires) together so they have one solid continuous connection and see if that helps.
Click to expand...
I'll give this a try, so basically make one continuous ground from all the green wires, will those go to the ground of the 9v power as well?
 
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Lower buffer:
Plug a guitar into GUITAR, plug a cable from TO PEDALS into your amp.

Middle buffer:
Plug a guitar into FX LOOP RETURN, plug a cable from AMP FX LOOP RETURN into your amp.

Top buffer:
Plug a guitar into FROM PEDALS, plug a cable from TO AMP into your amp.

Nothing else should be connected during each of these steps.
 
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Robert said:
Lower buffer:
Plug a guitar into GUITAR, plug a cable from TO PEDALS into your amp.

Middle buffer:
Plug a guitar into FX LOOP RETURN, plug a cable from AMP FX LOOP RETURN into your amp.

Top buffer:
Plug a guitar into FROM PEDALS, plug a cable from TO AMP into your amp.

Nothing else should be connected during each of these steps.
Click to expand...
Lower buffer works, but there's a slight hum.

Middle buffer works also with a slight hum.

Top buffer works with slight hum.

So everything is working correctly, just with a little hum coming through my 5150 2 on the clean channel.
 
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_aj666 said:
Lower buffer works, but there's a slight hum.

Middle buffer works also with a slight hum.

Top buffer works with slight hum.

So everything is working correctly, just with a little hum coming through my 5150 2 on the clean channel.
Click to expand...
Ok so last dumb question, since all buffers work and there are no issues when they are plugged in this way. Do I need to have everything plugged in to use this interface? I can't simply just plug in my guitar to guitar, and front of amp to amp and have it work? Everything needs to be plugged in to complete the circuit?
 
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That's correct, you'll have no signal if you do it that way.

At minimum you'll need a patch cable between TO PEDALS / FROM PEDALS.... or you could just plug your guitar into the FROM PEDALS jack.

You could add a wire between the switched tip lugs (that's the lug on the opposite side) of those two jacks so it makes that connection internally when nothing is plugged into them, then it'll work standalone like you want with no additional patch cables.
 
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Robert said:
That's correct, you'll have no signal if you do it that way.

At minimum you'll need a patch cable between TO PEDALS / FROM PEDALS.... or you could just plug your guitar into the FROM PEDALS jack.

You could add a wire between the switched tip lugs (that's the lug on the opposite side) of those two jacks so it makes that connection internally when nothing is plugged into them, then it'll work standalone like you want with no additional patch cables.
Click to expand...
Damn, so this things worked all along then. 😅 Yeah I might run a wire from those to just to have it as a standalone buffer when I'm messing with stuff. Thank you so much!
 
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Robert said:
That's correct, you'll have no signal if you do it that way.

At minimum you'll need a patch cable between TO PEDALS / FROM PEDALS.... or you could just plug your guitar into the FROM PEDALS jack.

You could add a wire between the switched tip lugs (that's the lug on the opposite side) of those two jacks so it makes that connection internally when nothing is plugged into them, then it'll work standalone like you want with no additional patch cables.
Click to expand...
Also, I understand what you're talking about. Any way I could get a visual. Maybe just draw some squiggly lines on the picture I provided. I'm going to go down and mess with it shortly.

Thanks again!
 
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