Making your pedals robust

[Kesh]

I don't mean the finish, I mean the workings: buttons, pots, jacks, circuit, wiring.

Pedals are meant to be stomped on for the whole of their working lives. What do people do to make these things survive the abuse?

[tubelectron]

Well, it's quite easy to built abuse-resistant hardware units, once the finish problem solved (much more difficult IMHO) :



A+!

[Kesh]

Well those are very pretty, but I'm more interested in how the PCB and wiring is secured, how much torque was on the nuts or whether they are glued, whether the battery is enclosed in something or just free to rattle around.

And I'm not sure those LEDs are very safe, as they aren't recessed.

[NPrescott]

I'm not claiming extensive experience on the subject, as I'm not all that rough on my gear, but:

PCBs can be secured with PCB mounts, I don't do this unless the board is particularly large or contains some delicate component.

Wires can be (I'm having trouble thinking how to call it) double-threaded through-hole to relieve strain. If I'm concerned about it I'll strip a bit more off the wire than normal, feed it up through the bottom of the board and then down and through the next adjacent hole and solder both of them. This isn't really an option with PCBs but I like it all right for perfboard. I looked and the closest picture I could find is this, which gives you the general idea. I'm not saying my way is in fact improving the durability of my boards, I just got in the habit of it some time ago. I'll go ahead and say it before someone calls me out on it, but you don't ever want to rely on solder/soldered-joints for mechanical strength. I seem to see it more and more often, but I really think it's a bad practice.

I don't typically use batteries, but unless there is room in which the battery could run amok I don't typically worry about fastening it down. There is the option of battery compartments, but for me personally it's always been too much trouble/cost.

Also, I like to read things like NASA's workmanship pages. If I can attain something similar then my builds will probably outlast me.


What do you mean by 'glued', on the nuts? All I can think of is Locktite, which seems like overkill for stompboxes. I don't really consider how much I'm torquing down the bolts, which probably isn't a great sign, but there is the whole variety of strain relief washers to consider.

[digi2t]

Also, I like to read things like NASA's workmanship pages. If I can attain something similar then my builds will probably outlast me.

Thanks for that link. Very interesting.

[amptramp]

I am just finishing up a fuzz of my own design (with eight rotary controls) and one thing I did was build a second faceplate with holes for the anti-rotation tabs on each of the controls (7 pots and a 6-position rotary switch).  This faceplate is made of plexiglas and mounts behind the main aluminum panel.  But I still reef the control nuts down as hard as they will go - this is just to avoid mangling the wiring if the pots break loose, although I did try to make the tab holes as tight as possible.  If you have large knobs, you may be able to drill the faceplate and hide the holes under the knob.

I have a standard blue-body 3PDT stompswitch on the box but I am so disgusted with the gritty "ker-crunch-click" action I get out of it that I am going with an industrial limit switch and electronic switching next time.  Boss et all were not wrong to avoid true bypass.  BTW, I have compared the switch action with switches on expensive digital stompboxes and they are smooth with no gritty effect.  It pays to have the clout to set your own specification.

The LED in my design has a conical ring around it like the white box above which protrudes farther than the LED itself.

I use a wall-wart only with ±12 volt outputs.  It goes to a keyed 4-pin connector that cannot be mistaken for anything else.  If I were to use a battery, I would use a battery holder with it.  There are totally enclosed 9 volt battery holders with a slide switch on the side available at A-1 Electronics.

The PCB is mounted to three threaded hexagonal aluminum pieces which are screwed down to the bottom plate of the box.  I have a terminal board for connection of the board to various parts and a 15-pin card-edge connector for wiring to the controls.

The jacks are open Switchcraft type since the plastic ones seem to end up with an end float that may misalign the jack with the electrodes to the point where connection is not made.

I use a steel box with an aluminum faceplate and aluminum side panels.  This is an enclosure that was originally a control console for a slide projector used in a conference room.

[rockhorst]

Recently I've opened up some 'pro' pedals from smaller builders. You'll find anything from using sticky PCB stand offs to full pot/switch/jack integrated PCBs. If it stays in place, it'll usually stay in place. I use double sided tape that's used to hang mirrors on walls, so I guess it's strong enough.

[Kesh]

Thanks guys, this is all great stuff.

[garcho]

I always leave the anti-rotation tabs on. Seems like an easy enough thing to do to help prevent problems.
I've torqued pots and switches to the point of ripping the shafts out, but I mostly use cheap crap.
Radio Shack makes cheap little 9V battery holders that I attach somewhere on the inside with double sided foam hanging tape. Not a professional solution by any means, but it works well. They also make one of the best LED bezels I've found, with a nice rubber base that holds the LED and its leads firmly in place. The top of the LED (5mm) is level with the top edge of the bezel.
Nice idea for a thread.

[roseblood11]

My most important rules:

protect the pcb and its solder joints from any mechanical force. Never use pcb-mounted pots, jacks, switches, leds, whatever. Always use parts with solder lugs and connect them with stranded wire, never use solid wire (it will break itself or destroy the traces...). I use 0,22mm diameter, never thinner, but many people say that 0,14mm works fine.

Secure the pcb from floating around, but don't use glue - it's too hard to get it out again for repairs or mods. If you use screws, make sure to prevent the pcb from mechanical tension... If you use glue, at least don't cover parts that a) might fail quickly (transistors etc), b) produce heat c) degas (electrolytes in caps evaporate)
I use double-sided adhesive foam tape ( or sometimes velcro) to mount the pcb's solder side to the backside of the pots and I put another piece of foam material (non-adhesive) between the topside of the pcb and the cover of the enclosure to hold it in place.

Clean up everything carefully and prevent the pcb from oxidation. I clean the solder side of the pcb with a tooth brush and alcohol and when it has dried, I apply soldering varnish (for example, search for "SK10" at conrad.de).

Use high quality parts for footswitches and jacks. I think, the best value for money have the jacks from Rean (Neutrik makes them now) and the 3pdt footswitches from alpha (taiwan). But all of these switches aren't very reliable, it's better to use relais switching (maybe the version that mictester described) and a good, vandalism-proof (momentary) switch. (I still use 3pdt switches - too lazy to change my habits...)
Pots aren't that important, because most of them die slowly, you will hear when it's time to replace them, before they fail totally. I always use the 16mm pots from alpha taiwan.

Plan your pedal carefully. Keep as much distance between footswitch and pots or toggle switches as possible. Your shoe is the pedals natural enemy...

Use tooth washers for everything except toothaches.

[tubelectron]

My method is very simple : I use foam of different kind of material, size, thickness and compliance. It gently maintains the whole circuit and offer damping.







A+!

[Kesh]

Nice idea for a thread.

Thanks. i was thinking threads are mostly circuits and finishes, and this info is great for relative noobs like me.

[deadastronaut]

same as bruno:  i use old school foam too, cut to fit the lid,.........nothing in there is going to move.

i also use velcro now on the back of my pcbs, and on the back of pots and its very secure....but also removable in case of future modding..

i never use paint on boxes, i only etch a design on the top...no scratches, digs, paint peeling, chipping, waterslide edges etc.......painted boxes look great when done, but after a few months not so imo....plus i like the metal look.

i never use led bezels either, i drill a 3mm hole and superglue the led in place...they will never come out and remain low profile...

use good jacks.....

have a beer, done.

[mremic01]

I'd like to know what you guys are doing to your solid wire that makes it break. I've never had any problems with it and use it almost exclusively now.

[artifus]

i suspect the core is weakened when stripping too tightly. no probs here either. one metre of cat 5 cable = eight metres of single core...

[rousejeremy]

This thread has some great tips. http://www.diystompboxes.com/smfforum/index.php?topic=87179.0

[Mark Hammer]

Things I do to promote more dependable performance:

1) Better quality wire for battery snaps.  Cheap ones tear easily, so if I don't buy better ones, I make my own from dead batteries.

2) Heat shrink on all wire joints and all unused pot lugs.  Provides strain relief and helps prevent both wire fracture and unintentional shorting of contacts during pot installation.

3) Locking washers on jacks.

4) Application of some Stabilant contact enhance to pot resistive strips as "conductive prophylaxis".

5) Mounting the stompswitch as low as the chassis will permit, and in a location where it will encounter as little lateral pressure as possible.  Stompswitches are fundamentally one cylinder inside a larger one.  When you step "down" to hit them, you are also stepping a little sideways and forward too.  If the switch sticks out too far from the chassis, your foot applies more lateral leverage, eventually widening the outer cylinder and making for a more wobbly switch.

6) Quick in-and-out soldering for stompswitches.  http://www.youtube.com/watch?v=6uhDKFhqYnw

7) Wire that is thick enough to hold up, and thin enough to turn corners gracefully.

A bit of hot glue applied judiciously in places and to thngs that need a wee bit of stabilizing.

9) Making sure your wire is as long as it needs to be and not a lot longer.  Wire too short risks fracture.  Wire too long gets bundled up and risks being tucked away somewhere that it can produce parasitic oscillations.

making sure there is enough room between the stompswitch and any controls.

[Magnus]

Hello together,
I did not read the whole thread but I want to post something...

...I don't know what happens if you have an accident and step hard on a potentiometer-knob,
maybe the potentiometer gets damaged, also the switches, maybe they can be broken too.

But its the same as with other equipment - don't step on your guitarcable,
the jack can be broken and turn out or the amplifier falls off the large speaker (4x12)...

Don't drink too much alcohol on a gig 


Greetings
Magnus

[Paul Marossy]

...I don't know what happens if you have an accident and step hard on a potentiometer-knob,
maybe the potentiometer gets damaged, also the switches, maybe they can be broken too.

You can break a little toggle switch with a good whack on it, but breaking pots with normal use is pretty hard to do. [If they aren't plastic] you would have deliberately have to try and bust up the pedal to damage those (or maybe if severe damage happened to it during transit).

[Mark Hammer]

...I don't know what happens if you have an accident and step hard on a potentiometer-knob,
maybe the potentiometer gets damaged, also the switches, maybe they can be broken too.

That's a fair question.  The consequences can sometimes depend on what kind of pot and what kind of knob.  Some knobs fit over both the shaft and the nut at the base, so that the knob itself lightly touches the chassis.  In that case, stepping on the control places stress on the knob, but much less on the pot itself.

If, on the other hand, one uses a pot with a long shaft sticking out, and the knob leaves a lot of exposed shaft, then stepping on the control places more stress on the pot than on the knob.

Some pots will be very robust in their construction and handle it well, others not so much.

I'd like to get some of those little short-bat toggles like one sees on ZVex pedals.  Not only do they require less panel space to be able to get you finger behind the bat to move it, but they are less susceptible to being stepped on and broken.  Good toggle switches are a wonderful thing.