Author Topic: Building a Test Box  (Read 5617 times)

K3yPr0gg3r

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Building a Test Box
« on: July 27, 2016, 09:59:52 AM »
Hi,

Paul @ DIYGuitarPedals.com posted a video regarding building a test box for DIY pedals. He used regular "star wiring" on the 3PDT, and used low voltage leads, (with alligator clips on the end), for In / Out / Ground / 9V. I'm wondering if I can use a "breakout" on the 3PDT for easier connections? Planning on using either Ben's (RullyWow) basic, or Barry's basic (GTRPedals.com).

Thank you for the help!

m-Kresol

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Re: Building a Test Box
« Reply #1 on: July 27, 2016, 10:38:41 AM »
sure you can. just hook up the alligator clips to pads you usually connect to the main pcb.
I build pedals to hide my lousy playing.

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rullywowr

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Re: Building a Test Box
« Reply #2 on: July 27, 2016, 11:27:28 AM »
Absolutely.  Either the rullywow 3PDT or Barrys' will work just fine.

Once you get a build a test box you will wonder how you lived without it!  Alligator clips work just fine.  I prefer to use push in speaker terminals like these:



I just leave the four wires from the PCB under test (IN/9V/GND/OUT) a bit long, tin them with solder, and they are a breeze to hook up.  Once you verify your effect is worthy of boxing you can trim the wires a bit shorter to install in an enclosure.  If its not "box worthy" you can still come back to it really easily by hooking up the wires.



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K3yPr0gg3r

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Re: Building a Test Box
« Reply #3 on: July 27, 2016, 12:03:47 PM »
Great! Thank you both!!

m-Kresol

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Re: Building a Test Box
« Reply #4 on: July 27, 2016, 03:06:21 PM »
I have to disagree with Ben about the HiFi terminals. I used them on my testing rig and wished I had used alligator clamps. easier to hook up your board without having to use way too long pieces of wire on the board that you will trim later and most often throw out. ymmv
I build pedals to hide my lousy playing.

My projects are labeled Quantum Effects. My shared OSH park projects: https://oshpark.com/profiles/m-Kresol
My build docs and tutorials

alanp

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Re: Building a Test Box
« Reply #5 on: July 27, 2016, 11:04:18 PM »
Speaker terminals here.
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Stomptown

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Re: Building a Test Box
« Reply #6 on: July 27, 2016, 11:10:27 PM »
I like the speaker terminals as well but Felix is right that you will end up wasting a bit of wire in a the process so I'd take the that in to account for sure. One thing I would suggest is to add an audio probe to the testing rig so you can troubleshoot with it as well as test your circuits. 

rullywowr

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Re: Building a Test Box
« Reply #7 on: July 28, 2016, 08:28:17 AM »
I have to disagree with Ben about the HiFi terminals. I used them on my testing rig and wished I had used alligator clamps. easier to hook up your board without having to use way too long pieces of wire on the board that you will trim later and most often throw out. ymmv

I can see your point of view, however that's is exactly how I do it.  I tin the four leads (which stick into the speaker terminals) and leave them long on each project.   Projects not box worthy are easily hooked up in seconds without fear of shorting. 

I'd rather leave the four wires a bit long on each project than fiddle with alligator clips trying to grab onto 4 loose wires and keeping them from shorting out.  This goes especially when its flopping around my bench and a guitar lead is plugged into the rig.  The loss of 2-4 inches of wire length is literally pennies and doesn't bother me one bit. 

I like the speaker terminals as well but Felix is right that you will end up wasting a bit of wire in a the process so I'd take the that in to account for sure. One thing I would suggest is to add an audio probe to the testing rig so you can troubleshoot with it as well as test your circuits. 

+1!  Very easy to repurpose an old multimeter lead or make one out of a pen as Bean's great tutorial shows.  I need to do this.  I usually just grab a piece of solid core wire and tack a 100n onto it.



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K3yPr0gg3r

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Re: Building a Test Box
« Reply #8 on: August 04, 2016, 07:18:39 PM »
Hi,

I decided to go with Ben's suggestion, and build the box with a 4 way speaker terminal. Used some "basic" IN/OUT jacks, and Ben's 3PDT breakout. Problem is if I only have the DC jack connected to the enclosure, the LED is lit. If I touch either one of the IN/OUT jacks to the enclosure the LED goes out, and I think I'm getting a spark. Wired everything properly, grounds, 9V, signal wires to the IN/OUT. For now, I'll just use it with the jacks away from the enclosure. If anyone has any ideas, I'm open to suggestions...

Thank you

Stomptown

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Re: Building a Test Box
« Reply #9 on: August 04, 2016, 08:12:13 PM »
Pics?

K3yPr0gg3r

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Re: Building a Test Box
« Reply #10 on: August 04, 2016, 08:55:00 PM »
Yes, you're right. Sorry. Pic A is of the entire unit. Pic B is of the 3PDT. Pic C is of the socket for the LED...sorry little blurry. Hope these help.

Thank you

Stomptown

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Re: Building a Test Box
« Reply #11 on: August 04, 2016, 09:12:17 PM »
It's hard to tell but it looks like the input jack/ground wires on the left side of the 3pdt breakout are shorting out.  If not I would still check to see if you have continuity between the tips and sleeves of the jacks for some reason.

Edit: are you sure the 9V jack is wired up correctly?

Edit 2: Is the anode of the LED making contact with the metal tab on the 3pdt switch?  if so, that would short out the led when the jacks are grounding the enclosure.
« Last Edit: August 04, 2016, 10:10:25 PM by Stomptown »

K3yPr0gg3r

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Re: Building a Test Box
« Reply #12 on: August 05, 2016, 05:21:10 PM »
After looking at the signal wire on the IN side of the breakout, (in my magnifier), I do see that I scaled it while soldering the 3PDT! There's a bit of exposed wire about 1/8" of the way up from the connection into the breakout as well. That'll do it, huh? NEED TO BE MORE CAREFUL! Anyway, 9V is correct, and LED leads are about 1/8" away from the 3PDT metal tab. Is it prudent to use a socket on the LED or should I go with direct contact with the breakout?
Also, as long as the lugs are horizontal does it matter which side is which with regard to the 3PDT? I notice there's a small marking on one side, and smooth on the other.
Doing a rebuild, I guess. All part of the pain of beginning.

Thanks

Stomptown

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Re: Building a Test Box
« Reply #13 on: August 05, 2016, 11:30:57 PM »
After looking at the signal wire on the IN side of the breakout, (in my magnifier), I do see that I scaled it while soldering the 3PDT! There's a bit of exposed wire about 1/8" of the way up from the connection into the breakout as well. That'll do it, huh? NEED TO BE MORE CAREFUL! Anyway, 9V is correct, and LED leads are about 1/8" away from the 3PDT metal tab. Is it prudent to use a socket on the LED or should I go with direct contact with the breakout?
Also, as long as the lugs are horizontal does it matter which side is which with regard to the 3PDT? I notice there's a small marking on one side, and smooth on the other.
Doing a rebuild, I guess. All part of the pain of beginning.

Thanks

I've never seen anyone socket the LED.  It's probably more pain than its worth.  The 3pdt can be oriented either way.  I usually have the notched side facing to the bottom of the enclosure for aesthetics.