Two Switch Things in Schematic

Started by Nobisayzhoi, July 19, 2018, 12:52:43 AM

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Nobisayzhoi

Hi, I'm very new to making pedals, and I've been coming across schematics like this with two or three symbols for a switch writen. Could someone please tell me what to do in both these cases?




diffeq

These are dual throw switches. An arrow depicts a switch's contact throwing between either one of those dot points.

Regular 3PDT stompswitch that you see as bypass has three of those. Hence the name - 3 Poles Dual Throw.

duck_arse

[pedantic] hrm. the first drawing actually implies two separate switches, because a) they don't have a dotted line linking the two halves, b) they don't have an explicit name like SW1A and SW1B, and c) they are drawn opposite sense, that is one is up while the other is down. c) is plain bad drawing practice, as it requires the reader to translate the schem to the mechanical and the mech isn't possible. if that isn't a double pole double throw switch, the previous doesn't apply.

the second drawing is acceptable within these <pedant> delimiting tags, tho I seem to recall there are bad sense switches on one or more kitrae schems.
[/pedantic]
don't make me draw another line.

merlinb

Doesn't have a little arrowhead but it's the same thing:

Mark Hammer

On rare occasions, "two switch things" can be uncoupled.  For instance, the classic EHX Small Stone pedal uses a DPDT slide switch (toggle in more recent issues) to accomplish several tasks at once: increase/decrease feedback, and change the LFO so that the speed range is altered and the LFO waveshape is altered to better suit the speed range.  Schematics may show the two switch halves as ganged, but there is no reason why they need to be.  The one switch could be easily, and productively turned into two SPDT switches.  I've done it, and it provides more options.

Just make sure that you understand the circuit, however, before attempting something like that with other circuits.  Sometimes it can lead somewhere useful...and sometimes not.

Nobisayzhoi

So for the second schematic,I should use a 3pdt?

idy

Yes, the second schematic shows one typical 3pdt bypass stomp. Two poles to control the signal, one to turn on the LED.