Smooth Stomp Switches.........Do You Know?

[Stu Diddly]

Hey Everyone,

I have a T-Rex Replica Delay pedal and I love how the switches feel.  They're almost effortless to cut on.  Some of these 3DPDT have to be pressed hard to cut on.  Does anyone know what type of switches T-Rex uses?  If so, where could I get some?  I'd love to start using these switches.  And yes, I have taken the pedal apart myself and looked at the switches and I can get any type of reading of them.  I do know that they are only DPDT switches. There are only 6 solder legs.

ANY HELP???

[Rodgre]

Are you sure that the T-Rex isn't using electronic switching with momentary footswitches that LOOK like standard footswitches?

Check it out at Small Bear.

Line 6, Tech 21 and Behringer use these types of switches to activate their electronic switching circuits.

Roger

[Stu Diddly]

Are you sure that the T-Rex isn't using electronic switching with momentary footswitches that LOOK like standard footswitches?

I don't think they're using electronic switching.  I just took some pics of my T-Rex, check'm out.









Shaun

[dschwartz]

they´re using two DPDT´s as SPST´s???

man, what a waist!!

[gez]

2 wires can't be true bypass, so the switches must be momentary and the switching electronic.

[JasonG]

Man that thing looks BAD. I wander what that transistor bolted to the side wall is for.

[i2k]

The smoothest non temporary footswitch I know is made by Alpha, as used by Marshall on their new pedals

[Mark Hammer]

1) If a momentary DPDT is the same size and price (or near enough) as a SPST momentary, then just about any manufacturer would prefer to have one big bin of switches that could be used for a variety of purposes, as opposed to one bin of switches that only had THIS many pins, and another that had more pins.

2) Just because it looks like a latching switch doesn't mean it IS.  If there is no discernible click, then it IS momentary, regardless of what it looks like.

3) Given what's inside it, the transistor bolted to the side of the chassis is more than likely a voltage regulator, using the chassis as a heat sync.  It is hard to imagine a delay pedal using more than an amp, or even anywhere near that.  So, even though use of a chassis as heat sync is not necessarily a best practice, in this instance the heat-sync needs are minimum, and the chassis provides stabilization (no wobble) of the regulator.

4) My old Boss BF-1, and many other pedals, used a latching stomp-switch to actuate switching FETs.  So even when it may LOOK like a true-bypass stomp switch, that is no guaranbtee that something other than straight-wire bypass is being used.  Personally, I don't consider that a problem.  I mention it only because some folks who think there is an equivalence between type of switch used and type of bypass method employed might, on occasion, be a little confused by what they see.

[gez]

2) Just because it looks like a latching switch doesn't mean it IS.  If there is no discernible click, then it IS momentary, regardless of what it looks like.

In addition, even if there is a discernible click that doesn't mean to say it isn't momentary.  I ordered a few momentary footswitches and, bizarrely, they click when you depress them.  They're not latching, so presumably this is done to let you know you've made the connection.  Wow, thanks, I'd never have guessed!  Currently residing in my parts bin, gathering dust...

Edit.  Actually, now that I think about it the manufacturers probably just use a single switch for both momentary and latching, only they disable something in the momentary ones so that they don't stay depressed.  Either that or the git who sold them to me passed off some duff latching switches as momentary!

[Mark Hammer]

Actually, it IS possible to convert a latching into a momentary.  One of these days, when I have the time, I'll try and do a photo essay showing how to alter the inside so that the little wobbly bits inside don't stay in place.  Alternatively, if you have the time and money, buy yourself a nonlatching stompswitch from Small Bear or wherever, open it up, open a latching one up, and see where the diferences are.  Trust me, there is not a whole lot going on inside there.

[R.G.]

I don't think they're using electronic switching.  I just took some pics of my T-Rex, check'm out.

Wow - you'd think they'd use a cleaning step after wave soldering to get the flux off that board. Could be no-clean flux, I guess, but it's still ugly.

The guys are right, it's either electronic switching, or DSP no-switching. In a pedal with digital conversion (and this one is) there is really no need to switch signals at all. The programming routine can just accept suggestions from the user through a switch to change from delaying or otherwise modifying the signal to not modifying it at all, just shoveling it from input to output. In some ways that's cleaner. You don't have that option in analog.

It's worth noting that it is entirely possible to use latching switches as momentary switches if you already have a clot of logic available. A few gates will make a single pulse out of a change in stage. With as much logic going on as is necessary for a modern delay with tap tempo, that's very much a possibility, and might be an advantage in using up a leftover stock of alternate action switches rather than scrapping them.

Edit: Mark, you hafta quit posting while I'm typing... 

You're entirely right - the inside of the switch can be nobbled too.

[Stu Diddly]

You guys are right, the switch does not click when you press it.  That's what I love about these switches.  They're effortless to turn on and off. I'd love to try and put some of these "type" of switches in some of my pedals.  Can anyone direct me to where I can buy them and how I would wire/make them work.

Thanks!

[gez]

Actually, it IS possible to convert a latching into a momentary.  One of these days, when I have the time, I'll try and do a photo essay showing how to alter the inside so that the little wobbly bits inside don't stay in place. 

Do they still make a click once converted, Mark?

[Mark Hammer]

Ideally, they shouldn't.  Essentially, the click is an audible byproduct of the plunger inside suddenly slipping into a position and getting stuck there.  When you step on the switch, you basically provide some play so that the plunger can move around and move the rocker contacts inside.  Those rocker contacts are little see-saws/levers that pivot on a fulcrum provided by the common contact in the center.  The play provided allows the plunger to slip into whatever position it isn't in at the moment, and when it suddenly slips and bangs into place, you hear a click and feel it.  You should be able to do something inside that allows the plunger to move the rocker contacts but not become lodged in the position.  Depending on the innards of the switch itself, that could be simply removing something, deforming the plunger in some way or perhaps some other physical feature inside.  You have to take it apart to see.  happily, they CAN be reassembled in most cases, if you keep all the parts and are able to crimp the tabs properly during re-assembly.

[gez]

Thanks Mark.  It seems that mine are intentionally made to click.  Weird!

[Ardric]

they´re using two DPDT´s as SPST´s???

man, what a waist!!

They could have at least wired the two sides of the switch in parallel.  Free redundancy.

[gez]

Can anyone direct me to where I can buy them and how I would wire/make them work.

You need extra circuitry to make them work.  The pedal needs an input buffer for starters.  Then you need a latch/flip-flop and a few other bits and pieces to control your switches, which will either be FETs, CMOS switches or Relays (additional circuitry required).  My advice would be to look at schematics of commercial pedals - Boss, Ibanez etc - to see how it's commonly done.*

Mark mentioned that Small Bear sell them.  I tend to go for 'DJ supplies' places in the UK as they sell them cheaper than Maplin, and they're the same switch (nice, heavy-duty, silent switches).  Google 'momentary footswitch' and check data sheets (if available).

*Edit: I think RG gives an overview of momentary switching in his Technology of the Tube Screamer article.  There's also some info about 4053 switching (used in Dano effects) at geofex.  Andrew (tone God) has some stuff about latches and switching.  Get reading!

[ambulancevoice]

http://www.smallbearelec.com/Detail.bok?no=23

according to the small bear guy there quieter than your average switch

[Stu Diddly]

I guess that I have my reading and research cut out for me.  I just took one of the switch out of my T-Rex and took pictures of it.  It looks like it's a Maplin Switch because of the "M", but it also looks like an "Alpha" switch because of the engraving on the other side.  What type of switch is this?

[slacker]

They're Alpha switches. Maplins do sell them, but I guess the M stands for momentary, because I've got some latching ones of the same type and they've got an L stamped on them.