Pros & Cons of Mounting a 3PDT Directly to the PCB?

[Philippe]

This would certainly reduce stompswitch wiring time & chances are, it could be easily integrated into any PCB design layout providing the final circuit board & 3PDT enclosure mounting positions are taken into account earlier.  Of course PCB size & the extent of the circuitry itself might make this concept impractical in certain instances...probably best if at all, for smaller boards like a FF or a simple booster. Though it would require additional wiring-out points on the PCB for the 3PDT functions (LED, ground, input/output etc.) simply soldering in the stompswitch might save a little time & possibly make the remaining wiring easier/faster for some.

Are there any inherent problems with this approach & does PCB thickness (in terms of the continued pressure/stress of on-off switching ) become an additional  consideration? Would conventional nylon stand-offs offer sufficient PCB attachment? Come to think of it, maybe the stompswitch hex nut (providing it remains sufficiently torqued) covers all of these bases/queries.

Just curious if this approach is a viable 'short-cut' worth pursuing on a DIY level.

BTW, saw a similar concept being utilized on the new AM Astro Tone Fuzz.
www.analogman.com/astrotone.htm

[Taylor]

If the switch is the only thing the PCB is mounted to, there's no problem at all. You don't need to use standoffs when doing this - the switch is the standoff. The issues arise when you have other things board-mounted too - if the pots or the jacks are board-mounted, then having multiple rigid attachment points between the board and the box can potentially stress the board and crack it.

So, pros:
easier to wire

cons:
potential mechanical failure

You have to be more careful about drilling and mounting when you have everything board-mounted.

[TELEFUNKON]

Here`s wondering if this construction can be considered stress-free?  http://www.diystompboxes.com/smfforum/index.php?topic=82446.msg689956#msg689956

[Processaurus]

Consumer stuff all has board mounted controls, but we should remember you are literally stomping on these switches, in a way you wouldn't stomp on a dvd player.  Jacks that are boardmounted too, are trouble, as anyone who repairs music gear or their own stuff has found.  And so it isn't really saving time, if you have to fix your stuff every couple years.  Plus getting a 3pdt switch out of a PCB would be a thankless task, even with a desoldering gun or heat gun, because the lugs are so heavy...

It takes 10 minutes to hand wire a stomp switch, no big deal for one-offs.  Hand wiring controls like that offboard can make your DIY gear more reliable than pedals made in a factory that have a bottom line other than reliability.

[Paul Marossy]

Looking at it from a manufacturer's point of view, it's probably a wash cost-wise, but I suppose you could have a small PCB that the switch mounts to which is connected by a ribbon cable to the main PCB. That would be a built-in stress relief and would prevent mechanical failure other than the switch itself. And it would prevent wiring mistakes, which could happen when you are mass producing something using unskilled labor (ie minimum wage grunts).

[jkokura]

Looking at it from a manufacturer's point of view, it's probably a wash cost-wise, but I suppose you could have a small PCB that the switch mounts to which is connected by a ribbon cable to the main PCB. That would be a built-in stress relief and would prevent mechanical failure other than the switch itself. And it would prevent wiring mistakes, which could happen when you are mass producing something using unskilled labor (ie minimum wage grunts).

I have two pedals done that exact way. Also, recently I saw a guy who designed and had built a PCB that connected the power, input/output and the LED all to a hardwire switch. Thing looked awesome! He made it so it fit exactly in a 1590B.

Jacob

[Paul Marossy]

Looking at it from a manufacturer's point of view, it's probably a wash cost-wise, but I suppose you could have a small PCB that the switch mounts to which is connected by a ribbon cable to the main PCB. That would be a built-in stress relief and would prevent mechanical failure other than the switch itself. And it would prevent wiring mistakes, which could happen when you are mass producing something using unskilled labor (ie minimum wage grunts).

I have two pedals done that exact way. Also, recently I saw a guy who designed and had built a PCB that connected the power, input/output and the LED all to a hardwire switch. Thing looked awesome! He made it so it fit exactly in a 1590B.

Jacob

Huh, interesting. Seems like when you've thought of something, someone has already thought of it before you...

[Taylor]

The board Jacob is talking about is linked in reply #2 of this thread.

[jkokura]

DOH!

[Taylor]

It's definitely a nice-looking solution, and it's cool to take the "wrapper" [see Geofex] off the effect board so when designing new stuff, the new board only has the actual effect on it. No need to re-layout the same things over and over. I do wonder about reliability. I started a similar thread a while ago:

http://www.diystompboxes.com/smfforum/index.php?topic=79530.0

At this point I think board-mounted pots only is the way to go, then wire jacks, and I think I'm going to start doing a 3pdt pcb with a ribbon cable connecting it to the main board.

[Paul Marossy]

Ha, I didn't see that link. I guess that's a cool idea, but that PCB can get messed up just as easily as any other one. The input/output jacks are probably the most likely to fail in that arrangement if the nuts come loose. I've seen it happen on CryBabys.

To me, the most bulletproof arrangement is to not have the input/output jacks or the bypass switch mounted to a common PCB. So, as a manufacturer, it comes down to this: do you want longevity and are willing spend a little more on labor to accomplish that, or do you want to produce the product for the lowest bottom line possible and not be so concerned about it still being functional ten years after it was built? As a one man shop, I would want both.

[Top Top]

Consumer stuff all has board mounted controls, but we should remember you are literally stomping on these switches, in a way you wouldn't stomp on a dvd player.  Jacks that are boardmounted too, are trouble, as anyone who repairs music gear or their own stuff has found.  And so it isn't really saving time, if you have to fix your stuff every couple years.  Plus getting a 3pdt switch out of a PCB would be a thankless task, even with a desoldering gun or heat gun, because the lugs are so heavy...

It takes 10 minutes to hand wire a stomp switch, no big deal for one-offs.  Hand wiring controls like that offboard can make your DIY gear more reliable than pedals made in a factory that have a bottom line other than reliability.

Jacks boardmounted aren't a problem if they ALSO are mounted to the case with nuts. There is no stress on the board from insertion/removal if they have nuts mounting the jack to the outside.

On the other hand, I have seen in a lot of consumer electronics where they had audio jacks and power jacks that were board mounted ONLY, and indeed, these tend to be the first thing to go.

[mikemaddux]

where are you guys sourcing 3pdt with PCB mount?

I dont like using the solder lug for PCB mounting for obvious reasons....

[Philippe]

where are you guys sourcing 3pdt with PCB mount?
I dont like using the solder lug for PCB mounting for obvious reasons....

You've got to make your own PCB arrangements for this particular feature.

[Taylor]

I think most guys board mounting the 3pdt just use the standard solder lug version. There was a thread recently about sourching a PC pin 3pdt, didn't seem possible in quantities less than 1000. Small Bear does have a PC mount DPDT now, though.

[metallo]

Here`s wondering if this construction can be considered stress-free?  http://www.diystompboxes.com/smfforum/index.php?topic=82446.msg689956#msg689956

It cannot be unless you modify the PCB. The jacks need longer slots and not round holes. The jacks will then need to be secured to the enclosure first, and soldered in place on the PCB after. You should choose one point that will will stay fixed (usually the foot switch), then let the other points float.

If you first solder, then tighten, you risk mechanical failure and breakage in the PCB, the solder connection, or the jack PCB legs.

This and much more is explained in http://workmanship.nasa.gov/lib/insp/2%20books/frameset.html

[markeebee]

Here`s wondering if this construction can be considered stress-free?  http://www.diystompboxes.com/smfforum/index.php?topic=82446.msg689956#msg689956

It cannot be unless you modify the PCB. The jacks need longer slots and not round holes. The jacks will then need to be secured to the enclosure first, and soldered in place on the PCB after. You should choose one point that will will stay fixed (usually the foot switch), then let the other points float.

If you first solder, then tighten, you risk mechanical failure and breakage in the PCB, the solder connection, or the jack PCB legs.

This and much more is explained in http://workmanship.nasa.gov/lib/insp/2%20books/frameset.html

Surely it would be much easier to do it the other way round?  Drill the holes in the enclosure maybe 3mm larger than the jacks, so that the jacks themsleves are floating, but are rigidly soldered to the board.  That way, if there's any 'flex' when the switch is stomped the jacks won't lever against the enclosure, instead they'll be free to move up & down by a mm or so.  Unlikely that the top face of the enclosure will flex much more than that. The jack nut (and washer?) will be sufficiently large to cover the gap between the jack and the hole in the enclosure.

[Paul Marossy]

Jacks boardmounted aren't a problem if they ALSO are mounted to the case with nuts. There is no stress on the board from insertion/removal if they have nuts mounting the jack to the outside.

On the other hand, I have seen in a lot of consumer electronics where they had audio jacks and power jacks that were board mounted ONLY, and indeed, these tend to be the first thing to go.

Yeah, but it depends on the type of jack. On the type where the body of the jack does not protrude thru the mounting hole, the nuts can come loose and the solder joints can crack. I've seen it happen on CryBabys before. It's not often that it happens, but it can.

I agree, board mounted only jacks are very prone to having problems.

[Pushtone]

I bought a few boards that mount everything from forumite Soggybag a few years back.
Besides pads for the switch and jacks there is an open "perf" ares in the middle.

I really liked his design and parts layout. Although I did move the power jack to the rear on another use of this board.

This has been posted before but seems current with the discussion.




more pics with box...
http://www3.telus.net/david65/pedal-pics/red-llama/


Yes the circuit is a Red Llama

[darron]

just to add an old photo to the list:






it can be a cool way to mount the pcb securely... drill the holes well positioned and with the hole sized as such that the pins just squeeze through so that it is solid and rigid even before solder, so that you don't stress the joint.

it can mean though that there will be a big empty area on the board where it might be going over the in/out jacks which are usually above the switch.