is it possible to add a external switch for switch the "mode" of T-Rex Tremster?

[hendry-324]

hey guys!
"new" here, i've learn a lot here but this is my first post.
i love the tremster, and it stay on my board for a loooooong time.
and i just want a footswitch which can do the same job as the button "mode".
is it possible? i can't find any schematic of tremster. and it have tons of room inside the enclosure.
btw, i made lots of looper type switch and mod a few pedal, so, i think i can do some simple thing.

is it possible the add a footswitch or a foorswitch jack like morning glory red remote type thing on tremster?

thanks!

here is some shots inside the pedal, just in case.

[ElectricDruid]

Welcome Hendry!

It sounds like it should be possible. What we need to know is what type of switch the Mode button is. Then we'd find a footswitch that can do the same job and wire it in instead.

Can you find a schematic or take a photo of the switch on the PCB? (both sides, please!)

[hendry-324]

Welcome Hendry!

It sounds like it should be possible. What we need to know is what type of switch the Mode button is. Then we'd find a footswitch that can do the same job and wire it in instead.

Can you find a schematic or take a photo of the switch on the PCB? (both sides, please!)

hey! ElectricDruid! thanks for your reply!

SURE! it's take some time to take apart this pedal. the in/output is just squeeze in the hole.

here is the close-up shots(a lot), hope these would help. i can't find any schematic online. the only thing i got is the manual.

[idy]

The switch, is it latching? I.e you push it in and it stays in until you push again and it pops out?

Do you want to keep the old switch in and also have a foot switch? Or are you willing to sacrifice the push button?

just curious: The mode change is between tremolo and vibrato?

[hendry-324]

The switch, is it latching? I.e you push it in and it stays in until you push again and it pops out?

Do you want to keep the old switch in and also have a foot switch? Or are you willing to sacrifice the push button?

just curious: The mode change is between tremolo and vibrato?

hey! idy! thanks for your reply!
it is latching, once push down and it stay until push again;

i'd love to keep the old switch and also have a foot switch, but if it need to be sacrifice, i'll take it;

actually, it switch between a soft and hard tremolo like the 'depth' control. because I leave it always-on in 'soft' mode, but I need to use the 'hard' mode in a few song for slide solo part. so, the idea of 'foot switch' control comes to mind. and I have the morning glory on my board. the red remote is pretty handy. the red remote is also latching switch. so I think it's kind of same thing.

but, the switch on tremster looks like a DPDT. so I have no idea how to add a foot switch to control that button.

[Kipper4]

Welcome hendry t the forum.

[idy]

Welcome to the forum.

With newcomers we never know what skill level we are talking to. The mod you are thinking of is a cool idea, but maybe not trivial. (but see**** below)

I think you would (might) have to remove it... you will definitely want to think this through before destroying your favorite pedal...

May be possible to remove it from PCB and then put  substitute switch in its place in the box, but you may not have much room in that solid block of pcbs and components.

You can look at the PCB and see how many pins the switch has. DPDT means 6 pins, it may have extra that are just for strength, and those may even go to the ground plane or something... Without a schematic we don't know much. This might require six wires to your remote switch, possible with some kind of multi-pin cable, not just a 1/4 TRS. (but see **** below!)

But I hazard the guess that it is not possible w/o removing the switch. You are going to have to break the contacts it is making and then remake them with the remote. Some kind of switching jack where when the remote is not plugged in things return to normal, and when it is plugged in the old switch is out of the picture. Bare possiblity of breaking a (few) track(s) on the PCB and then running wires from both sides of the break to your remote switching jack...not trivial.

If you are willing to give up the old switch, you still need to figure out how many wires you are talking about.

****On the bright side, if it is only a depth adjustment, it may be a SPST really, a resistor being cut in and out!

[hendry-324]

Welcome hendry t the forum.

thanks, mate! \m/

Welcome to the forum.

With newcomers we never know what skill level we are talking to. The mod you are thinking of is a cool idea, but maybe not trivial. (but see**** below)

I think you would (might) have to remove it... you will definitely want to think this through before destroying your favorite pedal...

May be possible to remove it from PCB and then put  substitute switch in its place in the box, but you may not have much room in that solid block of pcbs and components.

You can look at the PCB and see how many pins the switch has. DPDT means 6 pins, it may have extra that are just for strength, and those may even go to the ground plane or something... Without a schematic we don't know much. This might require six wires to your remote switch, possible with some kind of multi-pin cable, not just a 1/4 TRS. (but see **** below!)

But I hazard the guess that it is not possible w/o removing the switch. You are going to have to break the contacts it is making and then remake them with the remote. Some kind of switching jack where when the remote is not plugged in things return to normal, and when it is plugged in the old switch is out of the picture. Bare possiblity of breaking a (few) track(s) on the PCB and then running wires from both sides of the break to your remote switching jack...not trivial.

If you are willing to give up the old switch, you still need to figure out how many wires you are talking about.

****On the bright side, if it is only a depth adjustment, it may be a SPST really, a resistor being cut in and out!

wow! thanks for your time! you are so kind!
well, i notice that it's lot more complicated than what i think.

yep, you're right, it's very difficult do anything without schematic.
here is what i got, i use the multimeter(analog) to measure the DPDT, i don't know this would help or not, no matter this 'mod' can be done or not, I just wanna learn something.

and again, thank you guys so much! here is just amazing!

[idy]

So your little map tells us the switch is working as a single pole. Many times builders use a double switch for single pole for two reasons:
1)they only buy one kind of switch for both purposes, and
2) by using a double pole and soldering both poles together they make a more reliable switch. Ever have pedal where the toggle sort of works when you wiggle it, and sort of doesn't? Redundancy means reliability.

You would be better to number the terminals like this, the convention is:
1  4
2  5
3  6
Here the two poles are 123 and 456. 1 and 4 are soldered together. 2 and 5 are also soldered together. When plunger is down, 2+3 and 5+6 are connected. When up it is 1+2 and 4+5.

It is possible 3 and 6 go nowhere.... you would have to poke around and "trace" a bit of circuitry to find out. We see that when the plunger is down there is 300k between the top terminals and the middle. When the plunger goes out they are shorted. That could be enough to change the depth of the tremolo. It *might* be that simple. That would only mean two wires to a remote... But we need to be more sure. Can you see if the bottom two terminals are attached to anything else on the board? I mean, sure they are soldered in, but do the traces lead anywhere? Ground?

[hendry-324]

So your little map tells us the switch is working as a single pole. Many times builders use a double switch for single pole for two reasons:
1)they only buy one kind of switch for both purposes, and
2) by using a double pole and soldering both poles together they make a more reliable switch. Ever have pedal where the toggle sort of works when you wiggle it, and sort of doesn't? Redundancy means reliability.

You would be better to number the terminals like this, the convention is:
1  4
2  5
3  6
Here the two poles are 123 and 456. 1 and 4 are soldered together. 2 and 5 are also soldered together. When plunger is down, 2+3 and 5+6 are connected. When up it is 1+2 and 4+5.

It is possible 3 and 6 go nowhere.... you would have to poke around and "trace" a bit of circuitry to find out. We see that when the plunger is down there is 300k between the top terminals and the middle. When the plunger goes out they are shorted. That could be enough to change the depth of the tremolo. It *might* be that simple. That would only mean two wires to a remote... But we need to be more sure. Can you see if the bottom two terminals are attached to anything else on the board? I mean, sure they are soldered in, but do the traces lead anywhere? Ground?

got it! and here is 'corrected map':



**************************************************

here is the '6', there is a little 'wax' thing between the '6' and the hole beside. not 100% sure they're connect or not.



**************************************************

and '3', i can't find any 'trace' from '3'.

**************************************************

and '1', it looks like connected to a cap, here is the photo:





**************************************************
hope these would help.
big thank! mate! it's lot of fun doing this! \m/

[idy]

The little hole is called a "via." It serves to run a trace from one side of the board to the other. A wormhole. Keep looking. Trying to prove/disprove... pins 3 and 6 connect to nothing. Check ground. Are they connected to ground?
Yes it looks like pin 1 goes to that cap...but that could mean a lot of things. Maybe the cap is ground...or 9v. Which end of the cap? The side marked "-"?

I am also thinking a quick and dirty, and safer way to do this. Leaving the switch where it is and just "tack soldering" wires to pins 1 and 2. These would run to your remote... the remote would only work when the button in pushed in...but maybe that would be Okay?

That you could also test without doing any violence to your pedal.

[hendry-324]

The little hole is called a "via." It serves to run a trace from one side of the board to the other. A wormhole. Keep looking. Trying to prove/disprove... pins 3 and 6 connect to nothing. Check ground. Are they connected to ground?
Yes it looks like pin 1 goes to that cap...but that could mean a lot of things. Maybe the cap is ground...or 9v. Which end of the cap? The side marked "-"?

I am also thinking a quick and dirty, and safer way to do this. Leaving the switch where it is and just "tack soldering" wires to pins 1 and 2. These would run to your remote... the remote would only work when the button in pushed in...but maybe that would be Okay?

That you could also test without doing any violence to your pedal.

copy that! 
i'll keep checking the '3' and '6', try my best to prove it! also the 'cap'.
um.... i have no idea what is 'tack soldering', is it mean solder just a bit just for testing? if it work, then make a solid soldering, right? i'll google and youtube about it!

update:
ok, here is lot more complicated.
A, pin 1 is going to the 3.3uF (+) side.
B, after cleaning the '6' a bit, then show up that pin 6 IS connect to 'something' which include a BC546 and goes to 68k resistor and seems also another BC546(the 'trace' is across the bottom but I can't make sure that it is the end of this trace or still going to somewhere.)
C, pin3, i'm pretty sure it going nowhere.

here is the photo: