Pedal kit with no wiring / all parts on PCB?

[MrHat]

Hi all,
I'm sure I came across a video on youtube a while back of a company that produces a stompbox pedal where all the components where soldered directly to the board.  So the 1/4" sockets and the footswitch and I guess the 9v DC jack too.  I cant seem to find the supplier now though.  I really like the idea of doing things this way.  Any ideas of pcbs that are like this?  I think the PCB was the full size of a 1590b case with the corners cut out to match the case.

[R.G.]

I don't know what that was, but beware of the reliability of setups like this.

I design similar stuff for my day job, but I spend a lot of time taking into account the idea that you have to make sure that components fixed rigidly to a PCB and to a metal enclosure must do so without putting any bend, shear or flex on the PCB and by extension the solder joints on the parts. So the all have to be almost *exactly* the same height, which makes component selection picky.

It's also necessary that all the parts fix to one and only one plane. While fixing parts to two different planes is possible, it requires a lot of mechanical precision.

All that adds up to "worry about reliability when you put everything on one PCB". Sometimes you can, sometimes you can't, and sometimes you don't know until it's been built for a few months, which is worse than either of the first two.

[Processaurus]

It's also necessary that all the parts fix to one and only one plane. While fixing parts to two different planes is possible, it requires a lot of mechanical precision.

Yes, it has been a nightmare the couple times I've made a pedal with jacks, sticking out the sides of the pedal, and pots, sticking out the top, being mounted to the same PCB.  The problem is not only is the utmost precision with drilling necessary, but even if everything is perfect, it still can't really work nicely, because the jacks need to stick through the side of the enclosure (even the jacks with the screw in ends), but have to be able to fit within the boundaries of the enclosure walls in order to slide into the box to their holes.  Each time I've done it, it required either forcing the circuit board in by bending it (bad!!) or installing the jacks to the box, then soldering the board to the jacks, which means it needs to get desoldered from the jacks in order to get serviced every time.  Also the hammond type boxes all have slightly angled sides, so if the board is horizontal there is a funny angle between the jack and the side wall it is going through.

In addition, there are reliability issues with PCB mount jacks, the first time a plug gets stepped on the jack's solder joints will crack and make an intermittent connection, because the jack is  moving/being levered, but the PCB is being held rigidly in place. 

No, the jacks should be on wires, or on a separate PCB from the controls.

[R.G.]

No, the jacks should be on wires, or on a separate PCB from the controls.

Surprisingly, after making some mistakes, that's where the day job designs landed!   

[wavley]

It's also necessary that all the parts fix to one and only one plane. While fixing parts to two different planes is possible, it requires a lot of mechanical precision.

Yes, it has been a nightmare the couple times I've made a pedal with jacks, sticking out the sides of the pedal, and pots, sticking out the top, being mounted to the same PCB.  The problem is not only is the utmost precision with drilling necessary, but even if everything is perfect, it still can't really work nicely, because the jacks need to stick through the side of the enclosure (even the jacks with the screw in ends), but have to be able to fit within the boundaries of the enclosure walls in order to slide into the box to their holes.  Each time I've done it, it required either forcing the circuit board in by bending it (bad!!) or installing the jacks to the box, then soldering the board to the jacks, which means it needs to get desoldered from the jacks in order to get serviced every time.  Also the hammond type boxes all have slightly angled sides, so if the board is horizontal there is a funny angle between the jack and the side wall it is going through.

In addition, there are reliability issues with PCB mount jacks, the first time a plug gets stepped on the jack's solder joints will crack and make an intermittent connection, because the jack is  moving/being levered, but the PCB is being held rigidly in place.  

No, the jacks should be on wires, or on a separate PCB from the controls.

You could cut slots for the jacks like some of the newer EHX stuff.



I'm a fan of minimizing wiring as long as it doesn't sacrifice reliability, which it often does.  I love board mounted pots as long as there is some other mechanical support, unlike the Sunn Concert Lead I fixed this weekend where the board just hangs off the pots in a pretty high vibration environment, kind of a recipe for solder cracks.

RG is right, in a perfect world it would be easy to source parts that would be conducive to all being on the same plane, but unfortunately it's not the world we live in.  Back when I was a repair guy I made a lot of money fixing board mounted jacks and pots that weren't mounted with proper alignment and/or support.

I hate doing offboard wiring, but what I hate even more is taking every knob and nut off of something just to change one thing on a PCB, so you might also take that into consideration... as an extreme example, you need to change a shorted disc cap on a 16 channel mixer and it's on the pot side of the board, so now you have to undo 70 or so knobs and nuts to make two solder joints.

[MrHat]

Cool, some useful thoughts.  That EHX pedal looks really nice, it looks like it has a little ribbon cable going to the footswitch, very neat.  I guess the use of surface mount components makes this all much easier as there is more room to play with.  I was thinking that if you soldered the pots sockets and switch in in situ after you have screwed them to the case then they should be in the right place and not under stress.
I wonder how reliable the EHX stuff is, I have recently built a few kits (not pedals though) where I used ribbon cables for the first time and it was a revelation.

[marmora]

Not affiliated, but was it this:

http://www.arcadiaelectronics.com/

[R.G.]

I was thinking that if you soldered the pots sockets and switch in in situ after you have screwed them to the case then they should be in the right place and not under stress.

That's true - the first time it's opened up. The second through N times? Plan on re-melting the solder every time you move the PCB, or any control.

The instructions for mounting power devices on heat sinks say to mount them on the sinks, place the PCBs, fix the PCBs to the sinks, and only then solder the power device leads. Of course, PCBs attached to heat sinks are only rarely taken loose. Not necessarily so for effects pedals and controls especially if they don't work first time, every time.

The style of mounting jacks in slots in a cast box solves the fix-ed-ness in one plane. But what about the side to side dimension? The cast box sides are (and must be) sloped. What if there is pressure on the jacks from side to side, or if the lateral positioning isn't perfect? The nuts pull or push the jacks in the lateral plane. Making a big hole they don't touch is OK from this perspective, but what happens if someone steps on a jack plugged into the socket?

@Processaurus: In a perfect world - yeah, I wish! I spent a long time finding suitable families of parts for my day job. I wound up calculating the elastic coefficient of PCB stock, copper, and solder, both tin-lead and AG-Sn-Cu, as well as filtering through the min/max height tolerances of parts. Ugh.

[nosamiam]

The EHX design looks nice but I'm not sure if it solves the problem of breaking joints where the jacks are soldered to the PCB. It seems like it would make it worse. I've never seen it in person so I might be missing something.

What happens if you step on a plug? With them being only mounted in a slot instead of a hole, wouldn't the plugs try to exit the bottom of the enclosure, pulling the jacks along with them? It seems like stepping on a plug would exert a huge amount of force directly on the solder joints, especially if the jack's nut isn't tightened up all the way. What holds the jack in place at the top of that slot?

[aion]

Absolutely a bad idea. EHX does it, as mentioned, but their stuff is nearly impossible to take apart for modding or repair. I modded a Freeze pedal last year and everything was so tightly in place, I had to file down part of the enclosure to get the PCB out, and even then I put a lot of stress on the toggle switch - it was very close to breaking by the time the PCB came loose. EHX went with cost savings over repairability, same as most modern electronics - it's cheaper to throw it away and buy a replacement than to repair it. About as far from the spirit of DIY as you can possibly get

That said, EHX does some interesting things to help with strain relief - check out the inside of a POG2:



They cut slots around the jacks on the PCB so that the jacks can flex a bit without affecting anything around them. That's the clearest picture I could find, but they also do this on their 1590BB-sized pedals like the Micro POG and the Superego - not on the nano series, though, because the PCBs aren't wide enough to benefit from the slight flexibility.

[wavley]

Absolutely a bad idea. EHX does it, as mentioned, but their stuff is nearly impossible to take apart for modding or repair. I modded a Freeze pedal last year and everything was so tightly in place, I had to file down part of the enclosure to get the PCB out, and even then I put a lot of stress on the toggle switch - it was very close to breaking by the time the PCB came loose. EHX went with cost savings over repairability, same as most modern electronics - it's cheaper to throw it away and buy a replacement than to repair it. About as far from the spirit of DIY as you can possibly get

Cost savings has always been the mode of operation at EHX, I offered the picture not so much as good practice, but an alternative to what had already been mentioned.  That said, I have a soul food on my board, so we'll see how durable it is.  I don't really plan on tinkering with it because it sounds good and it's almost impossible to step on the jacks the way my board is laid out, so that kind of rules out everything but RG's great point about the sloped sides.  A friend gave me this because he knew I wanted a Klon and he was at a store that had two and bought both of them.  Of course the first thing I do (often before I even plug it in) is look inside and I was pretty surprised by the slots.  I haven't worked in pro audio repair (other than as a side hustle in trade for gear at a couple of places) for quite a few years now, so I hadn't seen that before.

Recently I fixed a blackstar for a guy, the tube sockets were wave soldered to the PCB with no standoffs to provide mechanical support next to the tubes when you changed a tube (and folks like to try different tubes).  I had to take every knob, jack, and nut off to fix one solder crack on a power tube (of course I resoldered all of them while I was there).  Needless to say, it took WAY longer to take apart and reassemble than it did to diagnose and repair... and repair guys charge you for that time.

Ribbon cables are awesome if you never plan on moving things, unfortunately when I build something I spend a lot of time tinkering with it getting it perfect and all that moving ribbon cables can cause problems.

[Mark Hammer]

I suspect that many of the absences noted in this thread are a byproduct of an approach to manufacturing that assumes no repairs to the product, merely disposal and replacement.  In many respects, when the product itself requires robotic micro-assembly, but also results in very low production costs and retail price-point, the likelihood of repair IS pretty low.  But when replacement involves several hundred dollars, as opposed to several dozen, you would think that it would be physically designed to be repairable.

[R.G.]

Of course the first thing I do (often before I even plug it in) is look inside and I was pretty surprised by the slots.  I haven't worked in pro audio repair (other than as a side hustle in trade for gear at a couple of places) for quite a few years now, so I hadn't seen that before.

The first thing I'd do is to chain-drill a cut across the slotted sections to free the jacks, pull out the board, then patch the cut with two wires across the chain-drilled cut. 

We rejected this style of strain relief in favor of mounting all jacks on a "jacks board" and then running wires to the main effects board. Our jacks boards are fixed in the plane of the jacks mounting, and the main board is fixed to the pots/switches plane, connected with wires. This cost us some for the wire insertion and soldering, but paid off - I don't know of any failures traceable to mechanical strains on the jacks/switches/pots.

Recently I fixed a blackstar for a guy, the tube sockets were wave soldered to the PCB with no standoffs to provide mechanical support next to the tubes when you changed a tube (and folks like to try different tubes).  I had to take every knob, jack, and nut off to fix one solder crack on a power tube (of course I resoldered all of them while I was there).  Needless to say, it took WAY longer to take apart and reassemble than it did to diagnose and repair... and repair guys charge you for that time.

When I was working on the Workhorse amplifiers, we went off interviewing techs about what to NOT do, and this was a big one. Every tech I talked to screamed about this. Modern Marshalls are a big deal - 20+ knobs and nuts to take off to get the PCB out before you can start debugging. Then you get to put them back on.

Ribbon cables are awesome if you never plan on moving things, unfortunately when I build something I spend a lot of time tinkering with it getting it perfect and all that moving ribbon cables can cause problems.

Ribbon cables were another of those gripes. Ribbon cables are reliable if they're never moved or if they have a mechanical strain relief to keep the soldered point from moving. Otherwise, the end wires get flexed proportionately more at the solder joint and break. Proper use of ribbons is to strain relieve the ribbon about a quarter of an inch/6mm back from the solder joints. But that costs about as much as you saved in using ribbons, so it doesn't get done.

[Mark Hammer]

When I was working on the Workhorse amplifiers, we went off interviewing techs about what to NOT do, and this was a big one. Every tech I talked to screamed about this. Modern Marshalls are a big deal - 20+ knobs and nuts to take off to get the PCB out before you can start debugging. Then you get to put them back on.

Now THAT is a focus group I would have loved to watch.

[wavley]

When I was working on the Workhorse amplifiers, we went off interviewing techs about what to NOT do, and this was a big one. Every tech I talked to screamed about this. Modern Marshalls are a big deal - 20+ knobs and nuts to take off to get the PCB out before you can start debugging. Then you get to put them back on.

Now THAT is a focus group I would have loved to watch.

Me too, I've got a lot of opinions about how things should be assembled (like the 8 layer circuit board I'm being asked to switch two high speed clock and data lines that are backwards using a gold wire bonder because of the 4mil traces and the speed requires the use of as short as possible using .7mil bond wires, but since it's 8 layers one of the lines the only place to do it is right at the card edge connector.  Ahh, radio astronomy... sometimes I miss working on modern marshalls)

[R.G.]

Me too, I've got a lot of opinions about how things should be assembled (like the 8 layer circuit board I'm being asked to switch two high speed clock and data lines that are backwards using a gold wire bonder because of the 4mil traces and the speed requires the use of as short as possible using .7mil bond wires, but since it's 8 layers one of the lines the only place to do it is right at the card edge connector.  Ahh, radio astronomy... sometimes I miss working on modern marshalls)

A friend of mine used to be one of the two people in the IBM panel manufacturing facility that was trusted to do "deep deletes" on mis-wired planar cards. Planar cards are - well, by now, probably were - about 12" by 18" circuit boards covered with holes on 100mil/2.54mm centers except where BGA chips or other special chips were installed. They got three wires between pads on 100mil centers.  The guy's job was to drill through up to four layers, picking spots where the drill would not cut traces on the outer layers but would cut a trace that needed cut on the inner layer. I was always amazed that this was possible by a human. 

[wavley]

Me too, I've got a lot of opinions about how things should be assembled (like the 8 layer circuit board I'm being asked to switch two high speed clock and data lines that are backwards using a gold wire bonder because of the 4mil traces and the speed requires the use of as short as possible using .7mil bond wires, but since it's 8 layers one of the lines the only place to do it is right at the card edge connector.  Ahh, radio astronomy... sometimes I miss working on modern marshalls)

A friend of mine used to be one of the two people in the IBM panel manufacturing facility that was trusted to do "deep deletes" on mis-wired planar cards. Planar cards are - well, by now, probably were - about 12" by 18" circuit boards covered with holes on 100mil/2.54mm centers except where BGA chips or other special chips were installed. They got three wires between pads on 100mil centers.  The guy's job was to drill through up to four layers, picking spots where the drill would not cut traces on the outer layers but would cut a trace that needed cut on the inner layer. I was always amazed that this was possible by a human. 

Geez, that's pretty amazing!  Sometimes as technicians it's our job to figure out how to do something that's next to impossible.  It never ceases to amaze me what folks can do, I'm just now starting to learn photonics and just came up from a lesson in single mode fiber splicing which is pretty amazing and delicate.  Now I'm going to try and do the other side of this board which won't lay flat on the hot plate (heat is a big part of wire bonding) and there are a lot of components and connectors that interfere with even our deep access bonder.  If I don't fix this then another board has to be ordered and stuffed and it will be my fault the project is held up... no pressure there! 

[Processaurus]

They cut slots around the jacks on the PCB so that the jacks can flex a bit without affecting anything around them.

The slots are interesting, but they don't seem to be for strain relief from plugs getting stepped on, because the wrong end is free; when the plug gets stepped on or kicked the nut end/sleeve end stays stationary and the tip end, the inside end wants to move.  Like a 1st class lever, a teeter totter.  The EH thing is set up like a 2nd class lever, a wheel barrow, so the sleeve end can move while the tip end stays stationary.  I think this is so they can shove the board into the box.  The jacks have to stick out into their holes a little, so it is a trick to get them to flex enough to get into the box, even though flat, the jacks stick out a little farther than the inside walls of the box.

It would be interesting to do the slots the other way, so the jack has a cutout around it on the three inside edges, only connected to the PCB on the edge of the board, the sleeve end of the jack, to make a hingeing arrangement.  The traces can escape the island on one of the hinges.  The fiberglass circuit board could probably twist/hinge a fair amount before breaking.

Maybe some day we'll be using floppy circuit boards that will solve all these issues!

[nate77]

This company named syntech or some similar to that had kits like you described. The battery jack is wired but the rest of the components  are mounted. You'll need to source your own enclosure but they are designed to fit a 1590b

[FUZZZZzzzz]

synthrotek was my first guess too:

http://www.synthrotek.com/kit-assembly-instructions/discontinued-products/pcb-mounted-only-tube-screamer/