Replacing a momentary switch with a jack...?

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MrDys
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Replacing a momentary switch with a jack...?

Post by MrDys » Tue Feb 23, 2010 1:56 am

So, I have my eye on the new Electro-Harmonix Deluxe Memory Boy pedal that's about to come out any day now. Tap tempo, BBD delay, selectable timing divisions, expression pedal (CV) input for controlling rate, depth, feedback, or delay amount, feedback loop for inserting external effects, square/triangle LFO modulation for chorus/vibrato...so yeah, awesome looking pedal.

I'm wondering if I can take out the momentary switch that controls the tap tempo and replace it with a jack, such that I can just feed it a clock from a sequencer or whathaveyou. Has anyone ever tried such a modification? Anyone have any ideas on what may be involved if I were to try to perform such a modification?
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A Dingleberry Monstrosity
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Post by A Dingleberry Monstrosity » Tue Feb 23, 2010 2:03 am

NO!!!!!

you could rig up a transistor switch and relay though.
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Post by meridic » Tue Feb 23, 2010 3:04 am

NO!!!!!
You sure about that? There is a fair chance the switch is just feeding logic, logic that could be just as happy with a gate or trigger signal as the +V from the switch. A switch debounce into the micro or logic they use to devise the tap tempo.

But the relay is the safest way for anyone who is unsure about electronics.

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Post by A Dingleberry Monstrosity » Tue Feb 23, 2010 3:16 am

I wouldnt try it, you really have no idea what that switch does.
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Post by money bags » Tue Feb 23, 2010 3:55 am

I wouldnt try it, you really have no idea what that switch does.
I would say try it and find out! you only live once, on that note :guinness: :drunkbanana:

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Post by meridic » Tue Feb 23, 2010 4:10 am

I would say see what the switch is connected to and make an educated choice

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Post by fonik » Tue Feb 23, 2010 4:30 am

i think the chances are more than good that it is just a debounced switch connected to +5V. use you DMM and tell us more.
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Post by MrDys » Tue Feb 23, 2010 1:02 pm

When it arrives, I will do some DMM probing...and then rely on y'all to tell me what to do next.
darenager wrote:I wonder how many people with Maths don't know it can file a tax return, or that Plague Bearer can indeed give bears the plague
suitandtieguy wrote:STG IS ALL ABOUT THE PLUR.

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Post by sduck » Tue Feb 23, 2010 1:55 pm

A Dingleberry Monstrosity wrote:I wouldnt try it, you really have no idea what that switch does.
If everyone had that attitude all the speak and spells in the world would still be unmolested and the world would be a safer place. :eek:
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Post by bwhittington » Tue Feb 23, 2010 2:07 pm

sduck wrote:
A Dingleberry Monstrosity wrote:I wouldnt try it, you really have no idea what that switch does.
If everyone had that attitude all the speak and spells in the world would still be unmolested and the world would be a safer place. :eek:

:lol:

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Post by falafelbiels » Wed Feb 24, 2010 8:46 pm

The Memory Man with Hazarai has has a very simple push to make switch affair going on. That should be easily accompanied by a CD4066 and some comparator opamp. Plenty of space in there!

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Post by A Dingleberry Monstrosity » Wed Feb 24, 2010 9:25 pm

sduck wrote:
A Dingleberry Monstrosity wrote:I wouldnt try it, you really have no idea what that switch does.
If everyone had that attitude all the speak and spells in the world would still be unmolested and the world would be a safer place. :eek:
With an external power supply you could seriously hurt yourself doing this if you screw up. Theres a reason why 99.9% of all circuit-bent instruments run on batteries.

feel free to stick your dick in an electrical socket it you want, but Im not going to.
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Post by sduck » Thu Feb 25, 2010 10:05 am

A Dingleberry Monstrosity wrote:
sduck wrote:
A Dingleberry Monstrosity wrote:I wouldnt try it, you really have no idea what that switch does.
If everyone had that attitude all the speak and spells in the world would still be unmolested and the world would be a safer place. :eek:
With an external power supply you could seriously hurt yourself doing this if you screw up. Theres a reason why 99.9% of all circuit-bent instruments run on batteries.

feel free to stick your dick in an electrical socket it you want, but Im not going to.
Didn't know it was externally powered. Be careful! (does that exonerate me?)
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Post by RF » Thu Feb 25, 2010 11:18 am

A Dingleberry Monstrosity wrote: Theres a reason why 99.9% of all circuit-bent instruments run on batteries...
'Cause that's the way the designer made them to run?

I'm not urging every 10 year old to start bending and modding things blindly - but, come on people - You really don't need to be scared of something just because it works on mains voltages. Even less so if it's using a wall wart supply.

On something with a wall wart supply it would take the 'perfect storm' of malfunction and/or stupidity to hurt yourself even slightly.

Use some common sense and you will survive the ordeal.

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Post by falafelbiels » Thu Feb 25, 2010 2:00 pm

why not take the power off while you are poking inside the echo? This is no bending so no need to keep it on. problem solved?

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Post by A Dingleberry Monstrosity » Thu Feb 25, 2010 2:06 pm

RF wrote:
A Dingleberry Monstrosity wrote: Theres a reason why 99.9% of all circuit-bent instruments run on batteries...
'Cause that's the way the designer made them to run?

I'm not urging every 10 year old to start bending and modding things blindly - but, come on people - You really don't need to be scared of something just because it works on mains voltages. Even less so if it's using a wall wart supply
batteries cant provide enough current or power to hurt you, worst case scenario you feel a tingle even that is a little unlikely I think. With an external PSU you could seriously zap yourself, yeah I doubt you could get killed but the possibility is there. There are caps in there that can hold quite a charge and if you touch them you will get zapped.

you ever heard the joke about charging up a giant ass capacitor then tossing it to someone like it was an apple? ZAP!!!!!

Im an electrical engineer btw, not bragging at all but I know what Im talking about.

Im not saying you CANT do this and you will definitely die, but the potential for getting seriously hurt is there and the chance of getting killed isnt zero.

*edit*

yeah all of this pertains to bending, if you check out what is going on while its powered up and you know you can wire it up for an external clock source and do the required modification while its powered off, yeah you will be fine. Worse case scenario you release the magic smoke.

just kind of went on a "bending tangent" there, my bad. :omg:
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Post by meridic » Thu Feb 25, 2010 2:14 pm

I think you are overly complicating things. To begin with, the mains voltage is not something you need to worry about, just unplug it first, you will not be playing with the mains voltage. Also the push button probably feeds a deboucer, which are very tolerant of what sort of signal they see. It is very likely you can just feed the debounce with a trigger, perhaps a diode on the input depending on what the debounce actually is.

If you want to do this and not wait for someone else to figure it out just go ask google about switch debouncing and spend an hour or two reading about it until it makes sense. Then open it up and trace out the circuit the switch feeds, then you can make an intelligent decision about how to proceed. This is easily in the grasp of even those without knowledge of electronics, you just need a little ambition and stubbornness. It may not work at first and you may fry something, this is where the stubbornness comes in, figure out why it did not work or what you killed and fix it. Ultimately you learn far more fixing your mistakes then you do when things just work right off the bat.

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Post by meridic » Thu Feb 25, 2010 2:20 pm

There are caps in there that can hold quite a charge and if you touch them you will get zapped.
Those caps are not holding mains voltage, they are holding the supply voltage, so maybe 15 Volts, likely less, and yes they can discharge and zap you, but these are probably caps of 1000uF at best, not 1F. If you are worried about such things just discharge the caps before poking around. If 15 Volts from a 1000uF cap is enough to kill you, you are in a very fragile state already.

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Post by JP » Thu Feb 25, 2010 2:29 pm

"batteries cant provide enough current or power to hurt you,"

Clearly never been tazered. ;-)

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Post by meridic » Thu Feb 25, 2010 2:33 pm

JP wrote:"batteries cant provide enough current or power to hurt you,"

Clearly never been tazered. ;-)
That is not quite being shocked by a battery, That is a battery through a DC-DC converter to get a high voltage to charge up a very very hefty sized capacitor. Capacitors dump their charge instantly, this is why they can be so nasty at high voltages.

There are batteries that can kill you, but not many people circuit bend diesel electric locomotives so we do not need to worry much about that.

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Post by JP » Thu Feb 25, 2010 2:53 pm

My point was that assuming "it's a battery it can't kill me" is not something I would live by.

Having being shocked by camera flash caps, I can tell you it hurts at the very least.

Just test everything with a multimeter. No one should be condoning touching anything electrical without first knowing what's on the other end of the wire. Multimeters are $20 these days, just poke around and see.

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Post by meridic » Thu Feb 25, 2010 3:02 pm

I know, my point was just to elaborate on what you said and try and avoid more assumptions.

Having being shocked by camera flash caps, I can tell you it hurts at the very least.
I did that once, trying to run a triode off of the DC-DC converter/reservoir cap from a disposable camera. Never returned to it after I shocked myself, it would not have worked anyways, at least not how I wanted it to.

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Post by A Dingleberry Monstrosity » Thu Feb 25, 2010 3:33 pm

JP wrote:My point was that assuming "it's a battery it can't kill me" is not something I would live by.
ok, replace "batteries" with "B, C and D batteries"

happy?! :tu:
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Post by A Dingleberry Monstrosity » Thu Feb 25, 2010 3:43 pm

JP wrote:Having being shocked by camera flash caps, I can tell you it hurts at the very least.
I worked with some bio med profs from my alma mater after graduation. The first project they had me do was to take apart this broken digi cam to get after the CCD array.

when I saw that giant ass cap I was like "...fuck.... um let me just short the pins with this screwdriver..."

BOOOOM!!!!!!!

screwdriver flew across the room and melted a little bit where it made contact with the pins. I started giggling my ass off because I wasnt expecting such a loud explosion. Thank god I looked away, I might have damaged my eyeballs.

I chopped the cap off and placed it on the table and continued working. A grad student came in to check out my progress and she was like "woah! You took out the cap? Did you shock yourself?!", "...no", ".....really? How did you do that?", "I shorted the pins.", "....what? man we keep shocking ourselves (her AND the bio med prof) on the other cameras..."
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Post by sduck » Thu Feb 25, 2010 4:14 pm

meridic wrote: There are batteries that can kill you, but not many people circuit bend diesel electric locomotives so we do not need to worry much about that.
But now that you've put the idea in my head...
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