Non-mechanical switching device?

[Hermansonsc]

Hey guys

I was playing with my band last weekend and I came up with a great organ effect using three separate effects and a volume pedal. The problem is, it's hard to stomp on three switches and get my foot on the volume pedal in the space between a chorus and a bridge.

I was reading about Neil Young's gear and how he controls all his effects from a separate switch box, and I decided to build a quadruple bypass box that will bypass up to four non-adjacent pedals on my board  with one stomp. My plan for this is to have a regular on/off stomp switch that controls a 9v current which goes to four non-mechanical (transistor?) on/on switches (one before each pedal) that will divert the signal to a bypass lead when the 9v current is on. This way I can kill the pedals that are plugged into the box without killing the ones between them.

So my two big questions are: is this a solid plan, and if so, what component am I in search of  for the non-mechanical switch operated by the 9v current?

Many thanks,
Stephen

[Plexi]

Do you mean some relay switch system?

[Hermansonsc]

That's exactly what I mean I knew there was a term for it, but I couldn't remember.  As you can tell, I'm very close to electronically illiterate.

Would that work? What's the name for that type of relay?

[ElectricDruid]

Relays would be one way, CMOS switches like the 4053 or 4066 would be another. More expensive and more modern alternatives of electronic audio routing switch also exist.
Relays is probably simplest, since it's essentially exactly the same as mechanical switching, but can be controlled from one switch. Electronic switching requires a bit more thought about biasing, and making sure DC blocking caps are in place and so forth. But R.G. has a good page about all this stuff over on his site.

http://www.geofex.com/Article_Folders/cd4053/cd4053.htm

Do you really need a quadruple bypass? None of these pedals are connected directly together?

HTH,
Tom

[EBK]

Do you really need a quadruple bypass?

Are you suggesting that, with proper diet and exercise, this probably could have been prevented?

[ElectricDruid]

That's right. Back off on the deep-fried mars bar and chips and get off the bus a couple of stops early and you'll be fine!

Trust me, I'm a doctor*

Tom

*This statement is purest fiction

[Hermansonsc]

Do you really need a quadruple bypass? None of these pedals are connected directly together?

Well I don't need four  this time, but I like to plan for unforeseen events.

I actually did a little research once plexi pointed out I was looking for a relay, and I came across cmos switches. That seems like a better fit than a relay. The 4066 looks good, from what I can tell. I'll definitely study up on that material. Thanks for the tip.

[Mark Hammer]

The contemporary fix for your problem is called a "loop selector".  All three effects are in the loop, and treated as if they are one big effect.  Hit the stompswitch on the loop selector, and all three effects come into play.  Hit that switch again, and they vanish.  You can just leave them all on, set the way you want.

Is that what you want, or have I read you wrong?

[Hermansonsc]

The contemporary fix for your problem is called a "loop selector".  All three effects are in the loop, and treated as if they are one big effect.  Hit the stompswitch on the loop selector, and all three effects come into play.  Hit that switch again, and they vanish.  You can just leave them all on, set the way you want.

Is that what you want, or have I read you wrong?

You read me right, except I'd rather build something quirky myself than buy a big ol' console for the front of my board. I'll probably spend more time and money on this than it's worth, but to me  that's basically the fun of it.

[Rixen]

Photmos relays also exist, which are the closest thing to mechanical contacts you can get in solid state for signals..

[PRR]

> a big ol' console for the front of my board.

For this purpose: one stomp-switch, four jacks. LED and power optional.

[Mark Hammer]

In fact, one can buy single-loop selectors in 1590A-sized enclosures.   If that's not small, I don't know what is.

[Joe]

I think relays would work really well for this, only need a single 2n3904 transistor to drive each one. I've used Kest DPDT relays for channel switching in the past, but I'm not sure what the ideal part would be for this application.

[Juan Wayne]

For the mechanical solution, add my vote on relays, and allow me to suggest the EB2 series from NEC/TOKIN, which I've done unspeakable crap to and are yet to let me down.

Not the cheapest ones (not crazy expensive either), but they're some sturdy, long living mother@#$%ers (spec'd at 10 million non-stop cycles) with a 2ms max switching time. You've got non-latch, single-coil latch and double-coil latch versions on a variety of voltages. And as Joe said, a simple transistor can drive them. I'd look into a proper driving circuit though, with fly-back diode and whatnot to prevent future (and likely on-stage) failure.

And while we're at it, another wild idea since the title asks for non-mechanic: how about copying Boss' buffered bypass as an alternative, non-mechanic solution? I know this is a love-hate thing for most people, but a buffer is always a good thing in a long chain, and if there's a time-tested solution out there, it's that one.

[Hermansonsc]

Lots of great suggestions, unfortunately the more technical stuff is Greek to me. As I understand it, the 4066 cmos switch is a pretty simple solution, so that's what I'm gonna shoot for. I may try a different option if I rebuild it in the future.

I'll post a chicken scratch schematic for input when I get it drawn up 

[digi2t]

I'll go out on a limb here, and recommend a (gasp!) non diy angle...

One of these,



With one of these,



Should be more than adequate to get the job done, and much more.

[Hermansonsc]

That's kind of using a shovel to swat a fly in this case. I don't have much interest in running my whole board this way, and I'm definitely not willing to spend over $400 on it. Plus, a big part of the diy route is using it as a learning experience.

[Quackzed]

as long as each of the 3 boxes you need to turn on/off together use momentary switches (most do unless they're 'true bypass')
you can simply add some sort of small 2 contact jack (dc jack is easy and 'drill hole' round) to each of the 3 pedals, wire each jack to the 2 pre existing momentary switch contacts inside each pedal, then wire all 3 to an outboard momentary switch via 3 more dc jacks... done.
you step on the external momentary switch and it switches all 3 as if you stepped on them all at the same time. done and very simple.
so it'd be (one small box for a momentary switch and 3 dc jacks)--->1,2,3, dc plug to dc plug wires going to the 3 repective dc jacks installed on the 3 respective pedals and wired to each pedals internal momentary switches contacts.
the separate pedals will still stomp on and off, when there is no dc plug connected.

actually it can be even simpler, no external box needed. if you just connect all 3 pedals momentary switches to each other via dc jacks stepping on any one of em will turn em all on/off. just make sure they're all off or all on when you plug em in... super easy, as long as they're not true bypass... (as long as they each use momentary switches to turn on/off  )

p.s. credit where credit is due; i believe this basic concept was suggested by Mr Mark Hammer as a simple remote effects switcher for commercial effects boxes in the past...

[Hermansonsc]

So I'm just now getting around to drawing a schematic (I got all the parts in the mail this week) and I realized the 4066 chip, of which I now have 5, is a quad SPST switch, not a quad SPDT. My original plan was to control the four switches in the chip with a SPST stomp switch in a 9v circuit to the chip. Now I'm thinking I'll use two 4066 chips, one for each signal path, and a SPDT stomp switch to select which chip has the 9v current.

Thoughts?

[amptramp]

You might want to design it as a make-before-break circuit so there is no time at which nothing is connected.  This connects both inputs together briefly so there is no audible switching noise when transitioning from one state to the other.  This is done by adding R-C networks that delay turnoff but not turn on.