Cannot replace Boss-type stomp switch with a 3PDT?

[Psychophonic]

I am still learning about mods and such. I do try to google and read before posting my questions here. If I understand my googler correctly, I cannot simply replace a Boss-type stomp switch with a typical 3PDT switch. Am I correct?

I have a Boss SD-1 knockoff in a plastic housing. My plan is to attempt a few of the SD-1 mods, and re-house the guts into a metal housing. I  would like to move/wire/replace the jacks and stomp switch away from the pcb. I am not trying to make this a true bypass unit. I just want to use a standard 3PDT switch when I make the move.

I seem to recall, but cannot find, a similar thread where someone suggested adding a remote 3PDT switch/enclosure and wiring it to 2 points on the original switch/pcb. Will this work? Would you need to make sure the original onboard switch is always "on" in order for the remote switch to work properly?

[bluebunny]

I cannot simply replace a Boss-type stomp switch with a typical 3PDT switch. Am I correct?

Yes, more or less.

There's a pair of JFETs in the Boss circuit that control what gets through to the output: either the effected signal or the dry signal.  The Boss switching turns either one of these on or off (and its counterpart off or on).  Read "The Technology of Boss/Ibanez bypassing" at Geofex for details.

So, with this in mind, you need to remove the JFET that would switch the dry signal.  And you need to jumper (drain and source) the JFET that would pass the effected signal.  This makes the original circuit "always on".  Then you can wrap the whole thing in a common-or-garden 3PDT switch circuit.  Note that this switches out the whole circuit (aka "true bypass").  It you want to keep the Boss buffering, then it's a little more involved.

[bluebunny]

In case it helps to understand what I wrote, here's the Boss schematic:



Q1 is the JFET that allows through the effected signal; this is the one to jumper.  Q2 is the JFET that passes the dry signal; this is the one to remove.  The flip-flop circuitry that would normally be controlling these JFETs is everything in the bottom-right quadrant.

[idy]

You have options. You can remove and jumper and then add a true bypass 3pdt;
or 2pdt and no LED
or 2pdt and Milenium or Rat "trick" LED switching...

Or use a new mechanical momentary contact stomp, 1pole switch. Taking the place of the tiny plastic switch thing pushed by the little plunger on the old pedal (or however they did it.)

Second way you keep your buffers and LED from the old.

But you are saying you want a mechanical 3pdt switch but not true bypass. Are you sure?

[Psychophonic]

Thanks guys, very much appreciated. Ok, the Geofex link is the one I had mentioned reading but could not find again. I am still struggling with much of the terminology due to lack of experience thus far. I will read and re-read it.

True bypass isn't a must but I suppose either way is fine by me. I've read that the buffer circuit isn't necessarily a bad thing if the pedal is placed at or near the beginning of the pedal chain?

After going back thru the Geofex article, I'm going to look for YouTube videos to see if anyone has made one for this purpose. It might help me better understand the Geofex info. I don't know the science behind baking a cake but I can follow a recipe well enough to produce a tasty cake, if that makes sense. For example, I followed the Stinkfoot Crybaby mods and eventually got it right. I was able to move my Crybaby into a desktop enclosure for my parked wah project.

"Just tell me how to do it" isn't what I'm after of course. I want to learn this stuff. For some reason it's just a bit of a struggle for me. The Crybaby mods were a great hands-on learning experience for me.

[antonis]

I've read that the buffer circuit isn't necessarily a bad thing if the pedal is placed at or near the beginning of the pedal chain?

It ideally is a good thing..

But single BJT simple buffers, like Q5 & Q6 in schematic posted by bluebunny above, are far away from been classified as ideal..
(the days of such effect bypass configuration utilized, 3PDT were both expensive & hard to find, compared to 2PDT ones..)

[Psychophonic]

In case it helps to understand what I wrote, here's the Boss schematic:



Q1 is the JFET that allows through the effected signal; this is the one to jumper.  Q2 is the JFET that passes the dry signal; this is the one to remove.  The flip-flop circuitry that would normally be controlling these JFETs is everything in the bottom-right quadrant.

The attachment isnt appearing on my end. SD-1 pcb diagram?

[antonis]

The attachment isnt appearing on my end.

Does it now..??
https://www.hobby-hour.com/electronics/s/schematics/boss-sd1-super-overdrive.webp

[anotherjim]

The Boss switching isn't necessarily a bad thing. A lot of top players had them in the chain and the transistor buffers are still doing "something" even when the effect is bypassed. As mentioned, a momentary action version of the stomp switch is all you need to replicate the little Boss keyswitch.

[Psychophonic]

The attachment isnt appearing on my end.

Does it now..??
https://www.hobby-hour.com/electronics/s/schematics/boss-sd1-super-overdrive.webp

Yes I see it now, thank you.

[duck_arse]

In case it helps to understand what I wrote, here's the Boss schematic:



Q1 is the JFET that allows through the effected signal; this is the one to jumper.  Q2 is the JFET that passes the dry signal; this is the one to remove.  The flip-flop circuitry that would normally be controlling these JFETs is everything in the bottom-right quadrant.

if you wanted to keep all the buffers and do least work, I think if you clip C15 and C16 out, and then lift the ground end of R27 and tie it instead to V+, the transistors should/might come up in the same state each time you power on, one on and the other off. if the led lights, all you need is to wire your bypass switch correctly.

[Psychophonic]

Well, unfortunately I don't think I'm ready for this project. I don't yet understand much of the terminology used in the advice given here. I just plain feel dumb at this point. I am grateful, and hopefully things will eventually make sense to me.

I searched YouTube for tutorials pertaining to what I am trying to accomplish and surprisingly found nothing. Closest I found was Isaac/Mammoth installing a mini pcb that seems to somewhat pertain. I'm sure Issac is both intelligent and knowledgeable, but every sentence is broken into multiple parts, separated with "uh...". I was done after 60 seconds of that.

I have managed to complete the Crybaby mods I mentioned, and built an ABY pedal by following a YouTube tutorial. So I don't feel completely hopeless. Someday.

[Mark Hammer]

[Psychophonic]

Thanks for posting, I watched it 4 times. I love the concept, but it doesn't seem practical for what I am trying to accomplish. I wouldn't have the time mid-song to bend down, pick up a cable, and touch it to the input jack. I am also trying to make it all happen inside the new housing, without using a remote switching box/pedal. However, if I watch the video enough times, and try to think it through, I may (or may not) be able to figure it out based on the video. Great idea though. This is probably child's play for most, I realize that.

[Mark Hammer]

The idea is that one runs simple 2-conductor patch cords to a separate momentary stompswitch.  I only demoed it by grounding the tip of a short cable because it was easier at the time.  Here's what I was intending.  I built it into the chassis of an old 4-button Marshall amp footswitch that I picked up cheap.  I added two holes for an additional pair of stompswitches.  The idea is that any Boss-like pedals using a momentary switch could be modded, as per the video, and cables runfrom the pedal to a completely passive switcher unit.  There's no real limit or requirement for how many switches.  I don't have a lot of Boss and DOD pedals, but they are all now modded to be able to implement remote switching in this fashion.  I hasten to add that this does NOT change their ability to be used in the "normal" way, or with a loop-selector.  It just lets you stick them where you want on your pedalboard and be able to turn more than one on or off, or flip between this one and that, with a single footpress; something you can't do with a 3PDT unless you have an expensive controller unit.  Admittedly, it's not a solution to everyone's needs, but it does present a simple, cheap, and problem-free solution to some people's needs.

Here's the front view of a control unit I made.  The switches are arranged so I can hit multiples, or individual switches.  The pair on the back row are set higher than the front to avoid accidentally hitting more switches than I want to,while still permitting a slight tilt of the foot to actuate two, or even three switches with one foot-press.

Here's the rear panel.  It's simply a set of mini phonejacks that allows one to connect whatever pedal you want to whatever jack you want.  Remember, the extension patchcords do NOT carry any audio.  The order of effects is set by how you patch the pedals together.  This "control base" merely dictates which combinations you've made easy to control in a single foot-movement.  Note that some pedals allow for a remote momentary switch to be used for tap-tempo.  Assuming such pedals use a momentary contact with ground to do that (easily recognizable if the jacks to be used are simple TS type), the control unit could double as both tap tempo switch and pedal on/off switches.

Finally, here's the inside.

[Psychophonic]

The idea is that one runs simple 2-conductor patch cords to a separate momentary stompswitch.  I only demoed it by grounding the tip of a short cable because it was easier at the time.  Here's what I was intending.  I built it into the chassis of an old 4-button Marshall amp footswitch that I picked up cheap.  I added two holes for an additional pair of stompswitches.  The idea is that any Boss-like pedals using a momentary switch could be modded, as per the video, and cables runfrom the pedal to a completely passive switcher unit.  There's no real limit or requirement for how many switches.  I don't have a lot of Boss and DOD pedals, but they are all now modded to be able to implement remote switching in this fashion.  I hasten to add that this does NOT change their ability to be used in the "normal" way, or with a loop-selector.  It just lets you stick them where you want on your pedalboard and be able to turn more than one on or off, or flip between this one and that, with a single footpress; something you can't do with a 3PDT unless you have an expensive controller unit.  Admittedly, it's not a solution to everyone's needs, but it does present a simple, cheap, and problem-free solution to some people's needs.

Here's the front view of a control unit I made.  The switches are arranged so I can hit multiples, or individual switches.  The pair on the back row are set higher than the front to avoid accidentally hitting more switches than I want to,while still permitting a slight tilt of the foot to actuate two, or even three switches with one foot-press.

Here's the rear panel.  It's simply a set of mini phonejacks that allows one to connect whatever pedal you want to whatever jack you want.  Remember, the extension patchcords do NOT carry any audio.  The order of effects is set by how you patch the pedals together.  This "control base" merely dictates which combinations you've made easy to control in a single foot-movement.  Note that some pedals allow for a remote momentary switch to be used for tap-tempo.  Assuming such pedals use a momentary contact with ground to do that (easily recognizable if the jacks to be used are simple TS type), the control unit could double as both tap tempo switch and pedal on/off switches.

Finally, here's the inside.

That's a very cool idea, thank you for sharing. I may be able to achieve my goal after all. By shortening the wires in your example, it seems like I could wire one of those type of switches directly to the 2 points on the original Boss-type switch. This would allow the new switch to exist within the same housing, and the original switch can be tucked away inside the new housing when I transfer everything over. Does this sound correct? If so, which type of switches are you using in your example? I don't think a standard 3PDT switch is what this job calls for, if I'm halfway understanding this.

[Mark Hammer]

The switches I show are simply SPST momentary switches. 

In terms of reliability, I doubt whether substituting one of them in a boss pedal itself will offer anything useful other than maybe one's personal preference for feel.  If the circuit is rehoused in another enclosure, however, yes, they will certainly do the job nicely, rather than having to figure out how to wire in a 3PDT of install the original Boss momentary with some sort of actuator.

Incidentally, there is absolutely nothing that would prevent you from rehousing in a Hammond-type enclosure with an onboard momentary stompswitch, AND installing a mini phonejack on the side or back for optional use of a remote switch when you feel that might have some use.  The one does not exclude the other.

But yes, you have the general idea.

[Psychophonic]

The switches I show are simply SPST momentary switches. 

In terms of reliability, I doubt whether substituting one of them in a boss pedal itself will offer anything useful other than maybe one's personal preference for feel.  If the circuit is rehoused in another enclosure, however, yes, they will certainly do the job nicely, rather than having to figure out how to wire in a 3PDT of install the original Boss momentary with some sort of actuator.

Incidentally, there is absolutely nothing that would prevent you from rehousing in a Hammond-type enclosure with an onboard momentary stompswitch, AND installing a mini phonejack on the side or back for optional use of a remote switch when you feel that might have some use.  The one does not exclude the other.

But yes, you have the general idea.

Is this the correct switch? I've seen 9mm and 15mm as the available options.
https://www.amazon.com/Guitar-Momentary-Effects-Button-Switch/dp/B00W93IWQA/ref=mp_s_a_1_6?dchild=1&keywords=spst+momentary+footswitch&qid=1596474634&sprefix=spst+momentary+footswitch&sr=8-6

[Mark Hammer]

Yes.

[Psychophonic]

Yes.

Roger that, it's been ordered. Thanks so much.