will one SPDT switch work for multiple inputs?

[acehobojoe]

If I am thinking of this correctly, a momentary soft touch switch just connects for a relay to be sent from your particular pedal. Could I use 2 mono jacks connected to the same momentary switch to bridge both of their connections, or would it cause some sort of mayhem in the current?  .. 

[mth5044]

Maybe a picture would help. I can't seem to divine what you're doing.

[acehobojoe]

yep, one second

[acehobojoe]

Like that, it's for a tap tempo with dual out.

or just click this

http://imgur.com/RgvnLGh

[R.G.]

That's a solid "maybe".

It depends not on the switch or the jacks, but what is connected to them. Some things will work fine, others will fight.

The only safe thing to do if you don't know exactly what will be connected is to use a double pole momentary switch. If you are making this for your personal rig and have the only two pedals that will be connected, you can try it with a single pole switch. You may get lucky.

[acehobojoe]

Alright . I'll just use a double.

[aion]

If you're doing it for tap tempo (which is usually pulling 5V to ground) you should be fine with multiple signals connected to one switch - just isolate each input with a diode.

One thing to mention ahead of time: you probably know this, but Boss delays need a normally closed switch, which is the opposite of literally every other tap tempo out there. So the tap tempo is tied to ground by default, and stomping the switch breaks the ground connection. So the following assumes that your taps require the same polarity.

Next: it's pretty simple, both input jacks should be wired to a diode with the cathode (banded side) facing toward the switch, then a wire to the switch. If you're in a small enclosure, the diode can act as your whole wire to save space.

Input jack 1 -> diode -> lug 1
Input jack 2 -> diode -> lug 1

Then lug 2 of the switch is wired to the ground of one of the input jacks.

Basically what you're doing is making it so the tap tempo jacks are isolated from each other. The diodes turn it into a one-way street, so both tap tempo outputs are connected to the tap switch (and to momentary ground) but not to each other.

[R.G.]

If you're doing it for tap tempo (which is usually pulling 5V to ground)

It's the details that get you. As I mentioned, if he has two pedals on his own rig he wants to work with one tap switch, he should just try it. Might work.

Delay pedals sometimes use 5V. Today, the DSP and uC world is moving to 3.3, even 1.8V, so what you get for a pullup is pot luck; depends on the pedal. You sure don't want to short a 3.3V pullup to a 5V pullup - especially in someone else's pedal. If he's getting ready to open his own cottage industry effects business, then he needs to be very careful about what pedals *might* be plugged into the switch, hence my question about whether it was for his rig or otherwise.

There are several other ways to organize a tap switch than open circuit closure to ground, as well as the issue that connecting the grounds through the tap switch and also through the signal shield conductor needs some careful thought.

On the other hand, if you have to pick luck or skill, pick luck. 

[aion]

Today, the DSP and uC world is moving to 3.3, even 1.8V, so what you get for a pullup is pot luck; depends on the pedal. You sure don't want to short a 3.3V pullup to a 5V pullup - especially in someone else's pedal.

Wouldn't the diode setup prevent any trouble with this? If there's a one-way path to (momentary) ground, there's no crosstalk between the pedals, at least outside of the tap enclosure.

That's not to say it would always work, e.g. with non-standard tap setups, but it at least should prevent any issues specifically caused by doubling up... right?

[R.G.]

Wouldn't the diode setup prevent any trouble with this? If there's a one-way path to (momentary) ground, there's no crosstalk between the pedals, at least outside of the tap enclosure.

That's not to say it would always work, e.g. with non-standard tap setups, but it at least should prevent any issues specifically caused by doubling up... right?

You're right, it will work for cases where the two pedals are close, with only different pullup voltages.

One possible solution to all (well, OK, much) of this is to use a transistor-output opto isolator for each tap output. That changes the task from fancy switch configurations to driving the input LEDs. Only down side is the need for power in the pedal and the current/voltage needed to drive the LEDs. Transistor-output optos are pretty cheap, perhaps cheaper than fancier switches.

[acehobojoe]

I'll just try the diode deal. I'm pretty sure both are just 5v. one of them is a strymon delay, and the other is a jhs panther. One will be this weird stereo setup, in which I believe you connect the sleeve and tip, and the ring does nothing.. I'll do a few tests.