Footswitch Building

[David Root]

Because commercial footswitches are grossly overpriced, and not all that roadworthy either, I decided to build a footswitch for my next build, 2-channel dedicated tubes design. It will have a short to ground SPST on each channel, before the tweed mixer stage, and a rolled off short to ground tonestack defeat gain boost SPST. The TS immediately follows the tweed mixer.

I bought a cast aluminum box and three Carling SPST footswitches from Lord Valve. The box is the same size as the old Phase 100. So I have tough enough components so far.

Now I need some suggestions/experience on connecting these three switches from the box to the chassis. I have been thinking XLR or DIN as I want only one cable.

[mhuss]

Most buildable-DIN plugs suck, they are not at all robust and reliable. You could use standard MIDI DIN jacks and then use a heavy-duty molded MIDI cable to connect it. I don't like any connector that doesn't withstand being stepped on, though.

Another option is to use a 3-pin XLR, male on one end and female on the other, then any bog standard mike cable will work both for normal use and in a pinch.

Oddball custom cables are a pain to replace (particularly when you notice you left it home after arriving at a distant gig! )

--mark

[David Root]

I think I agree with you. I had a Peavey Classic 50W I bought new in '75 that had a 9-pin DIN connection from a four switch box, so DIN has been used for a long time, but XLR just seems so much heavier duty, pro grade stuff. (And yes, I am an old fart).

I also agree with you that stuff should be able to withstand being stepped on. Y'day in my shop I almost crushed a reverb tank while working on getting its amp chassis into its cabinet. (While I'm at it, anyone got a foolproof method for drilling combo amp chassis strap bolt holes in the cabinet so they all always line up with the chassis holes? I had three perfect ones but the fourth was off a bit, and I was struggling with it when my foot hit the edge of the reverb tank).

I think I'll call Lord Valve again, he has lots of XLR stuff and he knows a bit about footswitches too.

[UR12]

Stereo 1/4" TRS (Tip ring sleve) also works great.

[David Root]

I didn't know there was such an animal. This is in 1/4" phono jack/plug size, right? Not miniature.

[mhuss]

Stereo 1/4" TRS (Tip ring sleve) also works great.

But not for *three* foot switches, as he described in his original post. On second thought, a stock mic cable only has 2 conductors plus shield too, duh.

Oh well, back to MIDI DIN or oddball (4-pin XLR, etc.)

--mark

[David Root]

Thanx for the help folks, I'm going to look up XLR stuff on the Switchcraft website, then talk to LV.

[Tonegeek]

Because commercial footswitches are grossly overpriced,

If price is a concern go with DIN and build two. The plugs are around 1$ and change, even cheaper for the chassis piece. I have used them for years with no problem. Even if you step on it, you can most likely get through the gig as the part that breaks is just the housing. you can still plug it in with no housing. Also, if you do get the 5 pin DIN in the semi-circular pattern, this is the same as MIDI and you can use a pre-made MIDI cables. If you are really cheap (like me!) you can use phone line extension cable. Just cut the ends off and solder the plugs on. They are tough/cheap although they don't lay flat on the floor due to the plastic is a bit stiff/light. I bundle mine with my send/return cables so it is not a problem. Somthing else to consider - if you put a plug on the footswitch, it is more likely to get stepped on. I usually hard wire mine with a plug only on the amp side. drawback to that is if the cable breaks on a gig, you have a different dilemma...

[Mickey_C]

a LAN cable?

Probably a dumb idea... they don't like being stepped on. Easily replaced though, and widely available.

[drz400]

Stereo 1/4" TRS (Tip ring sleve) also works great.

But not for *three* foot switches, as he described in his original post. On second thought, a stock mic cable only has 2 conductors plus shield too, duh.

Oh well, back to MIDI DIN or oddball (4-pin XLR, etc.)

--mark

You can do 3 mutually exclusive switches with TRS
So you use ch1, ch2, ch2with boost
Or with 2 buttons you can do A/B and have boost separate
If you add a 5 pin XLR you could add another separate boost as well
You could then have mutually exclusive A,B,C and a separate switch
for instance either 2 or 3 is shorted to ground and that channel is on, when neither is shorted the channel 1 is on. You can do this with two footswitches or with some simple logic you can do ABC

You can also have one swicth do A/B and the other switch something else
You can also do a voltage comparator to get a bunch more options.

[David Root]

Thanx for all your suggestions. I talked with Lord Valve but he had full-size XLR or DIN. The DIN stuff I have looked at was NOT roadworthy, and LV agreed. The full size XLR stuff obviously IS roadworthy, but a bit too big for this application, I think.

So I looked over Switchcraft's website and came up with what they call "TINI Q-G", which is sort of a half-size XLR system, nice solid metal construction, using a male chassis mount receptacle and female plug. I will hard wire the cable to the footswitch box with a strain relief, so no plug & receptacle there (these things are $10.00 each).

Where I'm at now is I would also like to have individual LEDs associated with each switch, soooo, (please correct me if I'm wrong) I will need 3 "signal" conductors for the footswitches, plus a common ground, then a fifth conductor paralleled to the LEDs, and a sixth conductor for the LED common ground, and the footswitches have to be DPDT. (Note that I'm not using relays here, all three switches are shunts to ground, so I can't connect the LEDs on the switch side of the relay). The LED power is a tap off the 12.6 VDC preamp tubes heater supply, (nod to drz400 there, this is a 4-stage preamp).

[drz400]

[quote="David Root"]

[drz400]

The LED power is a tap off the 12.6 VDC preamp tubes heater supply, (nod to drz400 there, this is a 4-stage preamp).

So back up here
The goal is 4 mutually exclusive buttons on the floor?
For instance, step on ch1 the previous channel goes off?
remember that you can have a light on the floor for lets say channel 1 but have the logic in the amp default to lets say channel 1 when nothing goes to ground
So 3 control lines can control 4 channels, then you need power and ground so you could do a 4 banger with a 5pin XLR.

Only trick is you need some active logic in the pedal but no big deal, there are a number of ways to do it.

[Funkalicousgroove]

Use a Ring-Lock Din, they are solid as it gets and come with up to 8 pins plus a ground connection, so you could have up to 4 buttons and 4 LED's

Mouser PN# 164-9380 for the 8 pin.

Belden makes non-shielded 22awg multi-conductor in as many conductors as you need.

[David Root]

Sorry drz400, I didn't mean to mislead you. There are only three footswitches and three LEDs. I mentioned the 4-stage design because in another thread you recommended 12.6 VDC heaters in hi-gain designs.

I did go ahead and buy the 6-pin half-size Switchcraft TINI Q-G XLR type female plug and male chassis receptacle, before coming back here. I pick them up today, so I guess I have a vested interest in using them now!

I wish I could upload the schematic I've drawn out but I don't have a scanner.

Basically I think I now need three DPDT footswitches which I would wire as DPST (not seen any DPST footswitches anywhere), with one pole for each ground shunt connection, the other pole for each LED, and two separate common grounds, one for each set of 3 poles. Total six conductors.

Now I have not used LEDs before. I have looked in the TUT books and there's tons of stuff about LEDs with all kinds of electronic switches that is way more complex than what I need. I believe LEDs need a resistor in series with them in the cross-line connection to prevent them burning out, and I have done that with neon HT pilot lights, putting 150K in to get the HT down to the 100V or so that the neon lamp needed.

Somehow I have the feeling I'm reinventing some kind of wheel here, and need some advice.