Poor man’s reusable Potentiometer breakout board – would this work?

[mkstewartesq]

I’m just getting into breadboarding and, since I’m not quite ready to get a Protoboard, I am thinking through ways to handle offboard wiring (I’ll use my Auditorium for power and I/O). At the same time, I’m also still doing stripboard builds and that can also be a real hassle to wire up pots just to see if I like the sound enough to put it in an enclosure. It’s a little bit more of a hassle for me than perhaps others because my number of PCB mounted pots far outnumber my solder lug pots so it’s a bit more labor-intensive to attach the wires to the pot.

ANYWAY …. I’m working on a strip board build of the Tim which has six pots with some slightly unusual wiring. So I tried to think of a way I could build a simple breakout board for pots for both breadboard work and for strip builds where I’m not yet ready to commit to soldering the pots in. With the following work/sound like a good idea as a poor man’s utility board for the time being?

1. One piece of stripboard approximately 110 mm x 90 mm. It has enough tracks that I was able to place six pots across this, each lug taking up a track with a track in between each log.
2. One row of female pin headers at the front to accept wiring from the bread board or stripboard.
3. A second row of female pin headers just behind the first to handle those (to me) weird situations where you are running wires between pots or linking lugs of the same pot (you know, “Treble 3 to Gain 1”, wire “to Volume 2 and 3”) so I can put jumpers between the appropriate pins on that row as necessary to connect lugs of of the same or different pots.
4. Finally, a few rows back, a third row of pin headers where you would actually insert the legs of the PCB mount pot.

So, if you’re with me so far, the first row of headers is going to go from the board to however many legs of the pots need to be connected to the board, while the row just behind it will only have wires running between headers on that same row as necessary to link legs of (the same or different (pots (for a given pot, there may be nothing going to the corresponding header in that second row if there is no linking to another lug or pot) and then the third row houses the actual pot. Obviously, all of these headers would be soldered in place and, for each track of the strip board, there would be a total of three pins – first pin to catch the inbound wire, second pen may or may not be necessary to make a second connection to that log, and the third pin down the track is where the actual lug of the pot would be.

I’ve already ordered the pin headers (because you can never have too many pin headers and I’m sure I’ll find a use for them) – but before I start soldering in probably 120 to 150 pin headers, thought it might be a good idea just to ask to make sure I’m not overlooking something big in my quest to be the next Edison.

Thanks,
Mike

 

[jwin615]

I like the idea!
Dupont wire for hookups-femalel to male, assuming you are using male male headers
Screw terminals for pot attachment
Or just use these

You can also use 9mm pots, madbean bread buddies and 9mm pots or twist the legs on 16mm pots but I don't like using 16mm pots on the bb

 

[BuddytheReow]

+1 for terminal blocks. Mounting pots with pin headers might damage the pot legs.

 

[mkstewartesq]

+1 for terminal blocks. Mounting pots with pin headers might damage the pot legs.

Thanks. I went ahead and ordered the terminal blocks (from Amazon, paying more than I would have if I had just thought about including them in the big Tayda order I placed two days ago). I personally don’t see how inserting the PCB mount pots into the pin headers would damage the pots – but I do think there is a risk, since it’s a tight fit, of the pin headers eventually failing from inserting and removing pots a lot, which either means desoldering an entire row of 50 – plus header pins or tossing the whole board and building a new one – so, yeah, the terminal blocks are a better idea for attaching the pots.

Thanks again.

 

[mkstewartesq]

Related question: what are some methods for easily connecting and disconnecting wires to switches when Brett boarding? Since the lig spacings are usually pretty tight, do you just use alligator clips and arrange them as carefully as possible to avoid a short?I thought about using female spade type connectors but it’s not easy to find them in 0.1 inch/2 mm sizes.

Thanks,
M

 

[mybud]

I personally don’t see how inserting the PCB mount pots into the pin headers would damage the pots – but I do think there is a risk, since it’s a tight fit, of the pin headers eventually failing from inserting and removing pots a lot, which either means desoldering an entire row of 50 – plus header pins or tossing the whole board and building a new one – so, yeah, the terminal blocks are a better idea for attaching the pots.

FWIW I need to reuse PCB-mount pots, so I use this kludge (female end to pot, male to board). It's not always ultra-reliable but it works.



WRT switches, I cut the female ends off the cable and solder the stripped and tinned ends to the actual switch. Same as above applies since the leads are fairly flimsy: again, a quick and dirty solution if one doesn't need to keep removing and restoring them on the board.



Here's the (finally!) functioning Simulcast test setup. I have tried various PNP Germaniums but settled on a top hat, which sounds slightly deeper than the OC75 I subbed for the more or less unobtanium OC71, which go for silly prices nowadays. These are suggestions based on what works for me so by all means take them with the proverbial pinch of salt.

BTW it's generally frowned on to insert pots straight to the breadboard as I do on occasion (bottom right). Best practice says that you risk damaging it thereby.

@BuddytheReow has the breadboarding thing down, so probably best to take his advice and ignore mine

 

[mkstewartesq]

FWIW I need to reuse PCB-mount pots, so I use this kludge (female end to pot, male to board). It's not always ultra-reliable but it works.

View attachment 92714

WRT switches, I cut the female ends off the cable and solder the stripped and tinned ends to the actual switch. Same as above applies since the leads are fairly flimsy: again, a quick and dirty solution if one doesn't need to keep removing and restoring them on the board.

View attachment 92715

Here's the (finally!) functioning Simulcast test setup. I have tried various PNP Germaniums but settled on a top hat, which sounds slightly deeper than the OC75 I subbed for the more or less unobtanium OC71, which go for silly prices nowadays. These are suggestions based on what works for me so by all means take them with the proverbial pinch of salt.

BTW it's generally frowned on to insert pots straight to the breadboard as I do on occasion (bottom right). Best practice says that you risk damaging it thereby.

@BuddytheReow has the breadboarding thing down, so probably best to take his advice and ignore mine

Thanks – yeah, I have the same goal of reusing the PCB pots, not just when bread boarding but also when doing strip board petals. If a build doesn’t work out, I wanna be able to reuse everything and I found that the heat from soldering and desoldering pot pins eventually does funny things to the pot (obviously), which is why I’m looking for as modular a solution as I can before I decide to definitively commit to wiring everything up and boxing the build. Appreciate your suggestions.

Nice Simulcast build!

 

[mybud]

Appreciate your suggestions.

Nice Simulcast build!

You’re most welcome and thanks. That particular build gave me endless trouble (mostly my confusion over which one of the three 100uF caps was in question), so nice to have it finally buttoned up.

 

[BuddytheReow]

For switches, I got some of these and installed sockets everywhere. I mount it on my breadboard's board with some sticky tack. Dupont wires work best here. I may have an extra one in my stash since the below is out of stock at the moment. DM me if interested, but I need to check my inventory before committing.

DPDT Wiring Board = 100's of Mod options. - GuitarPCB

The best mod board for your DPDT switch. Adding it to a 3PDT gives you an LED row!

guitarpcb.com

 

[Ginsly]

For switches, I got some of these and installed sockets everywhere. I mount it on my breadboard's board with some sticky tack. Dupont wires work best here. I may have an extra one in my stash since the below is out of stock at the moment. DM me if interested, but I need to check my inventory before committing.

DPDT Wiring Board = 100's of Mod options. - GuitarPCB

The best mod board for your DPDT switch. Adding it to a 3PDT gives you an LED row!

guitarpcb.com

I’d love to get some of these, but they always seem to be out of stock…

Is there a version of this on Osh Park or something? Otherwise stripboard it is! I like to support Barry but jeez, even the basic 3pdt pcbs are out of stock…

Edit: stripboard likely won’t accommodate dpdt lugs, hmm…

 

[BuddytheReow]

They will. You’ll need to use a small drill bit to make the holes bigger, but not big enough to break the copper track.

 

[mkstewartesq]

For switches, I got some of these and installed sockets everywhere. I mount it on my breadboard's board with some sticky tack. Dupont wires work best here. I may have an extra one in my stash since the below is out of stock at the moment. DM me if interested, but I need to check my inventory before committing.

DPDT Wiring Board = 100's of Mod options. - GuitarPCB

The best mod board for your DPDT switch. Adding it to a 3PDT gives you an LED row!

guitarpcb.com

Buddy – thank you. I’ll DM you. I actually really like Barry’s regular 3PDT boards because they are so flexible as far as connections and routing - I bought quite a few a while back and was planning on buying more, so it’s a bit of a bummer if it’s one of the many things he is currently out of stock on.

They will. You’ll need to use a small drill bit to make the holes bigger, but not big enough to break the copper track.

I’m still trying to figure out how this would work with strip board. With pots it’s easy – there’s one lug of a pot to a track. But with switches and inserting them directly into the stripboard, I’m not sure how you would arrange it so that you didn’t have at least two lugs on a given track. I may be just completely misunderstanding what you’re talking about doing (likely) or just too slow-witted to figure it out for myself (even more likely).
But I’m interested in finding out because the piece of strip board I’m using is fairly large and I was thinking about doing a series of cuts down the middle of it to effectively split it in two so that one side is for pots and the other side for switches. But I couldn’t figure out how to lay out the switch part.

Edit to add - wait .... maybe a cut on the tracks to separate the lugs on one side from the other, sort of like under an IC? Handle three lugs on three tracks on one side of the cut, and the other three on the same three tracks on the other side of the cut? Just spitballing. I have no idea what I'm talking about here.

M

 

[Locrian99]

i had bought a few ultra cheap breadboard and just put the pots pcb legs into the breadboard. I did mainly common values and didnt worry much about taper. Then would just run jumper wires to it. Im sure rhe breadboards were roached but they were the ultra cheapos

 

[mkstewartesq]

So, update:

It’s not pretty, but this is what I built. Terminal blocks to hold up to six knobs (I’m working on a build right now that has six pots), with two rows of pin headers behind – one row for the main connections to the pots, the second row for “jumper” connections – i.e., when two lugs of a pot are connected together or one lug of one pot is connected to a lug of another pot.

M

 

[mkstewartesq]

So, one more update, and probably the last one since we’re really near the end here.

I got it put together, and it proved quite handy for testing a six knob strip board build that had a fair amount of jumpers between the pots. Works like a charm. (Picture below- by the way, the reason that last pot appears to be suffering from depression is because it is a solder mount pot and I had to solder leads onto the lugs for it to work with the terminal – but I cut them just a little too short.)

That being said, there is a clear area where there is room for improvement. While the wires sit in the pin headers fairly snuggly, I still get a feeling of anxiety at how easily they could pop out, which means a lot of troubleshooting if a build isn’t working just because one wire isn’t making a good connection. So I think I’ll probably waste a bit of solder braid taking out that first row of pin headers and just putting screw terminals in its place so that the vast majority of wires are held tightly, and I’ll leave the second row of pin headers in place for the lug jumpers, since that situation doesn’t come up nearly as frequently and, even when it does, it’s not all that often that those jumpers run to the board where they can be easily pulled by shifting the board around while testing.

I appreciate all of you patiently watching me try to reinvent the wheel here.

M

 

[mybud]

Looking good …