Pedalboard Junction Box w/ Simple Jfet buffer

[Mike52]

So I built a simple junction box for my pedalboard that includes an input, output and an i/o audition loop for a volume pedal. I used simple JFet SMD buffers for the input and output but not for the audition loop (MMBFJ201). I essentially tried to build this project without the crazy expensive Creation Audio buffers. The idea is that I'd have a buffered signal going into the pedalboard and then a buffered signal going out to the amp. Maybe overkill, but it seems like a handy idea.

I noticed that it passes a signal just fine, the clarity is retained just fine, but that the buffered in and out experience a noticeable volume drop when compared to just using the un-buffered audition loop. To explain further, I put buffers on one input jack and on one output jack and also installed a courtesy 9v out so that I don't sacrifice a spot in my power supply.

Any ideas? Am I using the buffers incorrectly?

 

[MichaelW]

Can you post a picture of your wiring?

I just built something similar but I used GGG's IC buffer board and only have the loop itself buffered.
My version is True Bypass to the amp/interface.

 

[Mike52]

Yeah, I'll try to post something tomorrow after work. (I missed your thread. I'll take a look now)

 

[Mike52]

Here's some pics. I just ran a positive and negative jumper from the first power input to the power output (twisted pair). Otherwise, hopefully you can see the wiring. It's basically the same as the Vertex example I cited earlier. I soldered a wire to a flat washer to ground the case.



I tested both buffers on a breadboard before I installed them so I know they pass a signal.

 

[giovanni]

Did they have unity gain on the breadboard?

 

[Mike52]

I can't recall but I think I did. Otherwise I would have noted that as a problem when I was testing. I recall the tests being unremarkable as has been with other buffers I've breadboarded. "Is this thing on?" is the common reaction I have.

 

[giovanni]

And you are using the same JFETs? Can you show us pictures of the boards? Do both of them have the volume drop?

 

[Mike52]

And you are using the same JFETs? Can you show us pictures of the boards? Do both of them have the volume drop?

They are both J201s yes. Can't remember about the volume drop, but I can play with it this weekend to see if it is in both, cumulative or otherwise. The big thing I'm really not sure about was how to wire the 9v courtesy output. I just did a jumper between the two and am drawing power from the output for one of the buffers.

 

[giovanni]

Not sure I follow the 9V wiring. I meant did you use the same JFETs you used for breadboarding?

 

[Mike52]

I did use the same JFETS, yes. But as I said, I included a second 9v power jack so that I could daisy chain this pedals' power with another pedal so I don't waste a 9v output from my power brick. That "courtesy out" jack is the thing I'm not sure about. I've never wired one before so I just jumpered the power input supply to the second 9v jack.

 

[giovanni]

That should be fine. Wanna post pictures of the PCBs?

 

[Mike52]

Yeah, I can do that later on. It's tricky to take apart and I used solid core wire so it all comes out as one piece. Glad I used 9v "outies" instead of "innies," ha.

 

[MichaelW]

Yah, it's hard to get a good look at the buffer pcb's themselves. I'm also not familiar with those PCB mount jacks wiring. The only thing I can think of off the top of my head is that theirs an issue with one of the J201's. But with @giovanni's on the case and he's a lot smarter than me

I just used the Simple JFet buffer on another pedal build yesterday and it works great, nifty little board. But mine is a simple use case of a buffered boost pedal. (Amentum).

 

[Mike52]

Yah, it's hard to get a good look at the buffer pcb's themselves. I'm also not familiar with those PCB mount jacks wiring. The only thing I can think of off the top of my head is that theirs an issue with one of the J201's. But with @giovanni's on the case and he's a lot smarter than me

I just used the Simple JFet buffer on another pedal build yesterday and it works great, nifty little board. But mine is a simple use case of a buffered boost pedal. (Amentum).

Sounds like I should hear no volume drop through the circuit?

 

[giovanni]

Correct.