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Projects => General Questions => Topic started by: Tuxedo3 on February 02, 2017, 01:32:32 AM

Title: Junction box that sums to mono?
Post by: Tuxedo3 on February 02, 2017, 01:32:32 AM
Hey guys, I have a friend who was a sort of junction box for his board so he doesn't have to plug in and out of pedals to go to his amp. His last pedal is a BigSky, so he wants to run stereo from there to this box I'll make that has 2 inputs and 2 outputs. I was wanting to put a 1pdt switch on it so in one direction it sums both inputs to mono and the other it runs in stereo. Does this design sound like it would work?
Title: Re: Junction box that sums to mono?
Post by: jumokiezt on February 02, 2017, 09:25:08 AM
How wud that be done if so draw a diagram pleaze..

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Title: Re: Junction box that sums to mono?
Post by: jumokiezt on February 02, 2017, 09:25:45 AM


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Title: Re: Junction box that sums to mono?
Post by: sturgeo on February 02, 2017, 12:02:05 PM
Its not that straightforward, you need a circuit like this:

(http://i62.tinypic.com/sccbgl.jpg)

Info here: http://www.diystompboxes.com/smfforum/index.php?topic=112093.0 (http://www.diystompboxes.com/smfforum/index.php?topic=112093.0)
Title: Re: Junction box that sums to mono?
Post by: Tuxedo3 on February 02, 2017, 02:32:55 PM
Quote from: sturgeo on February 02, 2017, 12:02:05 PM
Its not that straightforward, you need a circuit like this:

(http://i62.tinypic.com/sccbgl.jpg)

Info here: http://www.diystompboxes.com/smfforum/index.php?topic=112093.0 (http://www.diystompboxes.com/smfforum/index.php?topic=112093.0)

and those resistors are 470ohm? That's interesting, but yeah I get it. Still not very difficult. Thanks for the schematic and info.
Title: Re: Junction box that sums to mono?
Post by: rumbletone on February 03, 2017, 03:14:11 AM
Have you tested summing it to mono? I am always hesitant to sum stereo effects to mono without testing - can create unexpected comb filtering/cancellation depending on the device and how it creates the stereo image. May be totally fine, but also may be better to just take the mono output when running mono.


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Title: Re: Junction box that sums to mono?
Post by: alanp on February 03, 2017, 05:56:24 AM
Passive mixing can be iffy. Probably be a better idea to have a simple op-amp mixer with some switches attached.
Title: Re: Junction box that sums to mono?
Post by: Tuxedo3 on February 03, 2017, 04:14:31 PM
The Goodwood Interfacer is basically where I got this idea. It has way more than just what I'm attempting to do though. It's an input/output function, buffer, kill switch, and has a tuner out, etc. But if you look, it has a switch that either sums the inputs to mono or runs them as stereo. I'd love to be able to do that, even if I had to run power to it, that's fine by me.

https://goodwoodaudio.com/product/theinterfacer/
Title: Re: Junction box that sums to mono?
Post by: Tuxedo3 on February 03, 2017, 04:24:52 PM
http://www.analogendeavors.com/product/custom-patchbay
This is the exact design I had in my head as well, that looks like a SPDT switch, I wonder how this one works?
(http://images.bigcartel.com/product_images/192344338/IMG_0943.JPG?auto=format&fit=max&w=2000)

http://www.analogendeavors.com/product/custom-patchbay
Title: Re: Junction box that sums to mono?
Post by: Tuxedo3 on February 16, 2017, 02:30:59 PM
In regards to this question, in case anyone ever is wondering in the future, I made this box to fill my needs. It's very simple (4 mono jacks and a SPDT) but the switch determines if the signal is summed to one jack or sent stereo.

(http://i.imgur.com/oeZH0R7.jpg)
Title: Re: Junction box that sums to mono?
Post by: AntKnee on February 17, 2017, 03:54:38 AM
Why doesn't someone offer a utility pcb for a pedalboard interface like this?
...or does someone?
Title: Re: Junction box that sums to mono?
Post by: sturgeo on February 17, 2017, 09:57:52 AM
Quote from: Tuxedo3 on February 16, 2017, 02:30:59 PM
In regards to this question, in case anyone ever is wondering in the future, I made this box to fill my needs. It's very simple (4 mono jacks and a SPDT) but the switch determines if the signal is summed to one jack or sent stereo.

Do you mean SPDT or DPDT? have you got a basic wiring diagram?
Title: Re: Junction box that sums to mono?
Post by: sturgeo on February 17, 2017, 10:09:19 AM
Quote from: Tuxedo3 on February 16, 2017, 02:30:59 PM
In regards to this question, in case anyone ever is wondering in the future, I made this box to fill my needs. It's very simple (4 mono jacks and a SPDT) but the switch determines if the signal is summed to one jack or sent stereo.

I've just noticed, you've not used isolated jacks on any of the ins/outs, do you get any issues with ground loops?
Title: Re: Junction box that sums to mono?
Post by: Tuxedo3 on February 17, 2017, 03:29:47 PM
Quote from: AntKnee on February 17, 2017, 03:54:38 AM
Why doesn't someone offer a utility pcb for a pedalboard interface like this?
...or does someone?

Working on it now actually  ;)

Quote from: sturgeo on February 17, 2017, 09:57:52 AM
Do you mean SPDT or DPDT? have you got a basic wiring diagram?

Nope it's just SPDT. I can take a photo of the inside if that helps. I never made a wiring diagram is just whipped one up with alligator clips and the jacks to make sure it worked first.

Quote from: sturgeo on February 17, 2017, 10:09:19 AM
I've just noticed, you've not used isolated jacks on any of the ins/outs, do you get any issues with ground loops?

I'm not actually sure what isolated jacks are, but nope, it's been working exactly how I imagined.