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DIY Stompboxes => Building your own stompbox => Topic started by: Valoosj on December 22, 2012, 08:32:23 AM

Title: Series/Parallel/Order Switcher
Post by: Valoosj on December 22, 2012, 08:32:23 AM
As I am building a thingamajig to test my pedals before putting them in an enclosure, I want to add the ability to test several pedals in different configurations without messing with cables. My goal is to have two loops which can be put in series or parallel and when in series, I want to be able to switch the order around.

I came up with this diagram using a 4PDT and a 3PDT.

(http://i69.photobucket.com/albums/i45/Valoosj/Thingamajig_zps848d5c36.jpg)

For splitter and blender I was thinking of the Runoffgroove SplitterBlend.
Is this plausible, or am I missing something?

Cheers
Title: Re: Series/Parallel/Order Switcher
Post by: Valoosj on April 03, 2013, 10:26:22 AM
I've finally come round to building this, and I ran into one slight problem. Send A and Send B both receive two signals, albeit only one at a time, depending on how the 4PDT is directing the signal. When I put the switch on the series setting, the signal is very quiet. One solution would be to add a SPDT at each send (for my convenience a DPDT) and use this switch together with the 4PDT as I cannot find a 6PDT toggle. But I do not want to do this.

Could I not just put a jfet buffer between each send jack and its two incoming signals? Or should I use a blender to blend the incoming signals, even though they are never used simultaneously?
Title: Re: Series/Parallel/Order Switcher
Post by: earthtonesaudio on April 03, 2013, 02:55:10 PM
When you put it into series mode, the input impedance of SND(x) is the regular input impedance of the thing attached to SND(x) in parallel with the output impedance of SPLIT(x).  So if you used ROG's Splitter/Blend for the SPLIT then the effective input impedance of SND(x) is going to be a few ohms.

Either:
a) Make your splitter's output high impedance, e.g. open-circuit or high series resistance
or
b) put a mixer on each of the SND nodes.
Title: Re: Series/Parallel/Order Switcher
Post by: remmy on April 03, 2013, 03:44:02 PM
Quote from: Valoosj on April 03, 2013, 10:26:22 AM
One solution would be to add a SPDT at each send (for my convenience a DPDT) and use this switch together with the 4PDT as I cannot find a 6PDT toggle.

I ended up using a 6PDT rotary switch for this purpose, works great.
Title: Re: Series/Parallel/Order Switcher
Post by: Valoosj on April 03, 2013, 05:10:00 PM
I used the AMZ splitter (http://www.muzique.com/lab/splitter.htm). Thanks for the replies. I've just found a cheap 6PDT rotary, so I'll use that as I do not feel like tearing the entire thing apart again to add necessary parts. Subbing the switch is easier to do.