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Need ideas for multi channel "rock before you box" rig

Started by rullywowr, September 08, 2013, 07:53:04 PM

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rullywowr

So I had a brainstorm last night.  If you are like me, you probably have a big bunch of populated PCBs that look something like this:



I thought it would be cool idea to have a breakout board (rock before you box rig) that has quick connections (4pin Molex), 9V power, in/out jacks, and a switch/led for each circuit.  This would make it easy to test multiple PCBs at the same time and switch the order quickly.  Make it easy to test different boosts before OD's and so forth.

Here is a crude mockup of what I envision:


I am just a little stumped on what the best switches would be for the circuits?  There would be one switch for each pedal connection circuit along with an LED.  Small size, common PCB mount components, and easy to implement would be a plus.  I don't mind if it needs a logic circuit or similar.

Here are some ideas I had:
1)  3PDT stomp for each one (too bulky/costly)
2)  Header pins with jumper shunts (kinda awkward but cheap and will work)
3)  Momentary with flip flop?
4)  4066 logic circuit?
5)  Relays (too expensive)
6)  PCB mount Slide switch?
7)  DIP switches?

I have some of these 2P3T from Tayda but not sure if they would work for the application.  They have 3positions which is weird.
http://www.taydaelectronics.com/electromechanical/switches-key-pad/slide-switch/slide-switch-2p3t-through-hole-0-3a-50vdc-1836.html

Any ideas would be appreciated.  Once this is complete, I am going to release it as open source to the pedal building community.  I plan on laying it out in Eagle and having some PCB's fabbed at OshPark for others to order.  A single sided version would be a bonus for you home etchers out there but it may have to be double sided.  Thanks in advance for any ideas.



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catfud

Just want to say what a really good idea I think this is. I've got a small bunch of working circuits but haven't boxed any yet, and it'd be great to hear them chained together before boxing. It'd also help work out the practical possibilities for intra-box circuit combinations before committing to boxing.

I know this looks like it's still at the drawing-board stage, but wouldn't the molex connected to the four cables using a clamp that makes it inconvenient to remove from the circuit cables easily? If so, I'm not sure how it might be done, but some sort of quick-release (maybe spring-loaded) way of attaching and/or detaching circuits to the molex cables would be nice.

rullywowr

#2
Thanks for the compliment.  Good idea btw.  For those who didn't want to molex all your pcbs you could make a molex to alligator clip breakout pigtail leads or even use pcb mount spring terminals or pcb mount screw terminals as well.  I am leaning towards the molex as it is self contained, small size, low cost and easy to wire up.  I could make a spring terminal pcb mount however it would take up lots more board space.  Perhaps putting molex and screw terminals in parallel would be the easiest option.



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rullywowr

Here is a mockup with Molex and screw terminals.  I ran out of 4 position screw terms so in the real version I would have them spaced out, not in a line like these are. 



Any switch ideas?   :D



  DIY Guitar Pedal PCB projects!

rullywowr

...doing a little research and thinking a Millenium Bypass to light up each led may work well.  Could use dpdt slide switches.  Thoughts?



  DIY Guitar Pedal PCB projects!

kothoma

Would you really need LEDs with slide switches? You can simply read the switches...

rullywowr

You are absolutely right about keeping it simple.  I designed a board last night with 4 channels and Millenium Bypass LED's, on board 1/4", on board PCB mount DC connections.  The final was pretty expensive to get fabbed and furthermore the LED's would remain on if there wasn't a circuit attached to the milennium bypass circuit.  I was thinking about adding a jumper, or you could put a wire between the unused ports GND and OUT however your idea is to keep it simple.

Looks like this:


I ended up trimming it down to the bare essentials and came up with a 4 channel rig.  It uses Tayda DPDT push buttons and has both screw connectors and Molex.  4-40 holes allow it to be mounted to the top of a 1590b and that will house the 9vDC jack and the 1/4" jacks.  Much smaller and easier to use.  Looks something like this:




It's kind of a simple thing but I really think it will be useful.



  DIY Guitar Pedal PCB projects!

rullywowr

#7
It's been a while but here is an update.

So I have been through a couple of revisions of the board and I have migrated over to Diptrace (from Eagle) in the meantime.  My goals were to have:

-Open Source (I will share the build files)
-Easy to assemble
-Will mount on top of a 1590A or larger enclosure using 8mm standoffs
-Enclosure will house IN/OUT 1/4" jacks and DC jack
-All components will be available from Tayda Electronics
-Includes both screw terminal and Molex connections.  The Molex will make it easy to connect various pedals in a different order, especially if you are not going to box them for an extended time.   You can also make an audioprobe which will plug into the Molex and other tools.

I will have 2 boards left over from my proto run at Osh Park if anyone is interested.  Here are some pics (the 3d model for the DPDT latching 6mm switch is not in the pics so there are just pads for now).










  DIY Guitar Pedal PCB projects!