Making your pedals robust

[artifus]

i've had quite a few cheap toggles fail with moderate use, never mind stepping on them. stepping on a pot could possibly bend the wiper and affect its contact with the wafer.

*edit* if your grub screw is tight, as it should be, then the pressure goes directly through the shaft regardless of knob skirt proximity to enclosure - and it can't be that close or else you wouldn't be able to turn it comfortably. half a mm would be enough to deform the wiper.

[Paul Marossy]

stepping on a pot could possibly bend the wiper and affect its contact with the wafer.

*edit* if your grub screw is tight, as it should be, then the pressure goes directly through the shaft regardless of knob skirt proximity to enclosure - and it can't be that close or else you wouldn't be able to turn it comfortably. half a mm would be enough to deform the wiper.

Look at the shaft arrangement on an Alpha pot sometime. The only way you're going to damage that is deliberately, with a lot of force. Accidentally stepping on it when using the bypass switch would do no harm to it whatsoever, it's not going to push in or something. It would take a pretty serious whack on those short shafts to bend them. I've seen a bent shaft on a Boss pedal once that someone wanted me to repair, but it did not affect the electronic functionality of the pot at all. For other brands of pots it might be a different story.

[artifus]

i didn't mention bending, breaking or otherwise damaging the shaft, i speculated on the damage that may be caused by stomping on or otherwise applying untoward pressure on the shaft and that which it is mechanically connected to.

[scott_v]

back on the foam idea... depending on the "type" of foam doesn't it "degrade" and fall apart (become brittle and flakey) over time?
The reason I bring this up is think of all those older MXR pedals and how that foam falls apart and infiltrates into everything (those poor pots!)
I just started using the type of foam that is used as packing material for shipping for a few pedals where i think its needed. 
Its got this sealed plastic surface, I forget what its called, its fairly thin though.  I'm not sure how it will stand up over time though too.

[Paul Marossy]

i didn't mention bending, breaking or otherwise damaging the shaft, i speculated on the damage that may be caused by stomping on or otherwise applying untoward pressure on the shaft and that which it is mechanically connected to.

OK, well try stomping on one a few times. Good luck breaking it!

[Mark Hammer]

back on the foam idea... depending on the "type" of foam doesn't it "degrade" and fall apart (become brittle and flakey) over time?
The reason I bring this up is think of all those older MXR pedals and how that foam falls apart and infiltrates into everything (those poor pots!)
I just started using the type of foam that is used as packing material for shipping for a few pedals where i think its needed.  
Its got this sealed plastic surface, I forget what its called, its fairly thin though.  I'm not sure how it will stand up over time though too.

I repaired a buddy's old EHX 10-band EQ last week, and the foam inside simply crumbled into a million pieces when I opened it up.  I've seen the same thing in MXR pedals from the same era as well.

It happens. I don't know that there is any way to avoid it, although it IS possible to avoid the mess part by simply replacing the foam every couple of decades.

I might add that the wires on the EQ had gotten "crunchy" over time.  Had to replace those too.

[amptramp]

Foam is bad news.  It doesn't keep the wires from flexing and it deteriorates over time, getting into pots, switches and jacks.  If you want some flexibility or damping, mount the board using grommets.  You can make a sheet aluminum board holder that attaches to the stomp switch itself.  Just a couple of 90° bends and you have a board support held in by the switch.  You can make similar brackets to attach to pots or jacks so you don't have to drill the case.

[Paul Marossy]

Foam is bad news.  It doesn't keep the wires from flexing and it deteriorates over time, getting into pots, switches and jacks.  If you want some flexibility or damping, mount the board using grommets.  You can make a sheet aluminum board holder that attaches to the stomp switch itself.  Just a couple of 90° bends and you have a board support held in by the switch.  You can make similar brackets to attach to pots or jacks so you don't have to drill the case.

You can even use something like that for a preamp tube as I did here:

[roseblood11]

wow, great!
do you have a template for that?

[Kesh]

You can even use something like that for a preamp tube as I did here:

Using the sockets and switch as fastenings is just genius. Will definitley be incorporating. Is it 1mm alu?

[DougH]

I mount my perf boards on standoffs and attach the standoffs with flat head screws that are countersunk. I can hide the screw heads with graphics if I want. Use lock washers for all the nuts. I use the chrome collets for mounting LEDs. DON'T put micro toggle switches on the top of the box (or anywhere, really). I avoid using switch options where possible, and if the function is important enough for a switch, I use another stompswitch. Don't try to cram as many controls, switches, etc as possible onto as small of a box as possible. What looks cute and clever on the workbench can become a real nightmare to use in practice. Give yourself some room for "stomping" with your feet. Go to the next bigger size box if need be; it's no big deal and it's not a contest. These devices are still relatively small, all things being equal. If you really do need a David Gilmour or The Edge size pedal board, consider sticking your pedals in a rack and using a remote switching system to save floor space (in addition to many other benefits).

[DougH]

Foam is bad news.  It doesn't keep the wires from flexing and it deteriorates over time, getting into pots, switches and jacks.  If you want some flexibility or damping, mount the board using grommets.  You can make a sheet aluminum board holder that attaches to the stomp switch itself.  Just a couple of 90° bends and you have a board support held in by the switch.  You can make similar brackets to attach to pots or jacks so you don't have to drill the case.

You can even use something like that for a preamp tube as I did here:

Now that's a good idea.  

Both Ron and Paul's ideas. The no-drill bracket idea is very appealing.

[Paul Marossy]

Hey guys, glad you like my Shaka Tube preamp tube mounting idea. I think I have a template for that bracket here: http://www.diyguitarist.com/DIYStompboxes/ST1590BB.htm

[Kesh]

Anyone know where I can get robust 9V battery leads?

[PRR]

> NASA's workmanship pages.

How Collins Radio made solid (big! old!) stuff:

http://www.jptronics.org/radios/Collins/Quality/collins_quality.1.pdf
http://www.jptronics.org/radios/Collins/Quality/collins_quality.2.pdf

[trjones1]

Go to the next bigger size box if need be; it's no big deal and it's not a contest.

Tell that to the guys in the 1590A thread  .  Seriously though, I love the 1590Q size.  I just wish it were more widely available (and cheaper).

[amptramp]

> NASA's workmanship pages.

How Collins Radio made solid (big! old!) stuff:

http://www.jptronics.org/radios/Collins/Quality/collins_quality.1.pdf
http://www.jptronics.org/radios/Collins/Quality/collins_quality.2.pdf

Love the Collins quality manual!  Much more applicable than the NASA quality standards.

Beware of following NASA standards indiscriminately - NASA standards (like NASA NHB 5300.4 for soldering) are biased toward light weight.  I once had our component reliability man show me a circuit board destined for the Hermes spacecraft (which we were both working on) and asked my opinion of the soldering.  I looked at it and said it looked like a lot of dry joints.  He said, "Look under this eye loupe - it is the best soldering you will ever see."  That was in 1975.  It is still the best soldering I have ever seen - but if I tried to duplicate the effect of minimum solder weight, I would get poor contacts.  The solder fillet went halfway up the terminals of leadless surface mount components (and we were using 54LXX series logic).  He was also critical of applying solder to one side of a hole and heat to the other.  By the time the solder wicks through, the side heat is applied to has oxidized.  You also don't need the parts of the NASA standards that deal with outgassing (cadmium and zinc plating were forbidden - the high vapour pressure of the metal would cause outgassing that would coat optical sensors).

One thing I miss about leaving the spacecraft business is the breathtaking workmanship.  The time I spent sitting at the feet of the master (the component quality guy) and learning about component applications was time well spent.  Unfortunately, he could only be reached via a seance now.

[tyzjames]

Here's how I build mine:
Single core 22awg wires with veroboard. Wires are twisted from pot to the board to give the board some support.


Add foam support below and above the board to keep it in place.

[tubelectron]

That kind of semi-compliant is very good too - I use it in the same manner in my pedals and also in old MXR pedals where the foam has crumbled.

In this tube pedal, I used a similar technique as Paul Marossy :



The power supply components (caps, rectifers, Xfo) are glued or screwed on a PVC plate fixed by the footswitch.
The circuit bracket holding the 12AX7 is fixed by the pots.
The circuit is point-to-point handwired with the help of a small turret bracket, and operates on HV.
Everything can be removed from the enclosure with only the PSU plug to desolder.

A+!

[stallik]

Interesting that so many are using packaging foam. The stuff being sold currently is marketed as being biodegradable. Only mention it as my experience of foams (and plastics) degrading is that it appears to happen suddenly. You know the kind of thing, one day the poly bag holding a million bits is ok, the next you're looking at a pile of bits and thousands of little shards of white stuff. I have a rack case which is lined with foam. It's a few years old now but in the last 3 months the foam has turned to powder. Might be worth making regular checks or does someone have a source of good old fashioned, bad for the environment, last forever stuff?