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DIY Stompboxes => Building your own stompbox => Topic started by: kitschead on April 13, 2014, 01:14:16 AM

Title: Momentary switch cuts out signal
Post by: kitschead on April 13, 2014, 01:14:16 AM
Hi guys. I built a switch pedal with a momentary and a latched DPDT.
The momentary switch seems to cut out the signal when its only half pressed which I'm finding really irritating cause it means I have to always remember to press it down quickly. Is this a fault which is inherent to the switch itself? If so how can I order a different switch and know that it won't do the same thing?
Thanks

Title: Re: Momentary switch cuts out signal
Post by: armdnrdy on April 13, 2014, 01:45:24 AM
I think you are going to have to give a bit more information than that if you want someone to help.

Do you have a drawing of the circuit?

If so, post it.  :icon_wink:
Title: Re: Momentary switch cuts out signal
Post by: kitschead on April 13, 2014, 01:54:04 AM
Sure
(http://i.imgur.com/ippgGfk.png)
The switch is based off this circuit
Title: Re: Momentary switch cuts out signal
Post by: armdnrdy on April 13, 2014, 02:00:56 AM
So one of these switches (S1 or S2) is momentary?

Is this so you can engage whatever effect on the fly by stepping on the momentary or engage it latched with the other switch?
Title: Re: Momentary switch cuts out signal
Post by: kitschead on April 13, 2014, 02:20:27 AM
Yep thats the idea. So either one of these switches is momentary. I use it with a delay pedal so I can briefly send the signal to a delay with the momentary switch or I can just engage the delay normally with the latched switch. Essentially its a circuit where one switch reverses the other. So whatever state the latched switch is in the momentary switch reverses it when it is engaged. In my setup the two paths are mixed with a behringer line mixer which fits nicely on my pedal board.
Title: Re: Momentary switch cuts out signal
Post by: merlinb on April 13, 2014, 07:52:43 AM
Sounds like you need a make-before-break switch. Either that, or a more sophisticated circuit. Your choice!  ;D

It's possible you could make something "good enough" by connecting resistors (470k say?) from the input to each of the two outputs, bypassing the switching as it were. So when the switch is half way, both paths are "on" to some extent, rather than both muted. Might require experimentation to find the best resistor values for your setup though.
Title: Re: Momentary switch cuts out signal
Post by: amptramp on April 13, 2014, 09:16:29 AM
You have invented the unburst box.
Title: Re: Momentary switch cuts out signal
Post by: kitschead on April 17, 2014, 12:26:11 AM
Ok cool thanks for the help.
Would you mind going into a bit of detail explaining that concept. I'm just trying to understand the logic of it.
Also could this result in a bit of signal spilling into the other output?
Title: Re: Momentary switch cuts out signal
Post by: merlinb on April 17, 2014, 03:51:48 AM
Quote from: kitschead on April 17, 2014, 12:26:11 AM
Also could this result in a bit of signal spilling into the other output?
Only during the split second when the switch is half way between contacts (which is the whole point really).
(http://i81.photobucket.com/albums/j207/merlinblencowe/ippgGfk_zpsbcf86dbf.jpg)
Title: Re: Momentary switch cuts out signal
Post by: ghostsauce on April 17, 2014, 09:34:52 AM
Very cool! You gotta tell us what effect you've got in that box though, for a strange use like this
Title: Re: Momentary switch cuts out signal
Post by: kitschead on April 18, 2014, 09:26:24 PM
I just use this as a momentary send to a MXR carbon copy  :)
Title: Re: Momentary switch cuts out signal
Post by: kitschead on April 18, 2014, 09:33:50 PM
Also would those resistors result in a much quieter sound?
Title: Re: Momentary switch cuts out signal
Post by: merlinb on April 19, 2014, 05:50:40 PM
Quote from: kitschead on April 18, 2014, 09:33:50 PM
Also would those resistors result in a much quieter sound?
Uh no... most of the time they're shorted out or shorted to ground. They only time they're "in circuit" is while the switch is in the process of moving from one position to the other.