Eurorack rotary switch module - 8 in 1 out

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groffcole
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Eurorack rotary switch module - 8 in 1 out

Post by groffcole » Wed Jun 24, 2020 9:34 pm

I'm looking for a eurorack module that does something like this:

- 8 inputs
- 1 output
- a switch that determines which input is routed to the output

I want to use this module to tune 8 VCOs. I want to tune the first VCO and then switch to the next, etc.

Does anything like this exist? Possibly as a DIY project?

Thank you.

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Flounderguts
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Re: Eurorack rotary switch module - 8 in 1 out

Post by Flounderguts » Wed Jun 24, 2020 10:00 pm

Super easy passive DIY project. 1P8T break-before-make rotary switch (Adafruit has them) and a bunch of jacks.
----------------------

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dubonaire
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Re: Eurorack rotary switch module - 8 in 1 out

Post by dubonaire » Thu Jun 25, 2020 12:42 am

Doepfer A-152

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Re: Eurorack rotary switch module - 8 in 1 out

Post by Rex Coil 7 » Thu Jun 25, 2020 2:03 am

dubonaire wrote:
Thu Jun 25, 2020 12:42 am
Doepfer A-152
Nice call. :)
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groffcole
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Re: Eurorack rotary switch module - 8 in 1 out

Post by groffcole » Thu Jun 25, 2020 9:37 am

I was actually thinking that I could use three spdt toggle switches to switch between the 8 inputs. I figure that three switches with two options each gives me 8 total possible configurations - kinda like a three digit binary number has 8 possible options.

000
001
010
011
100
101
111

Those can be three different switch values for each scenario, routing the input to the output.

For a simple module like this, would I need any "buffering"? I'm not exactly sure what that means, but I've seen it mentioned and used on things like multiples modules, etc.

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Re: Eurorack rotary switch module - 8 in 1 out

Post by BartBral » Thu Jun 25, 2020 10:39 am

Personally I would just stick to a rotary switch. Because that is the most simple approach. Otherwise (with the 3 switches) you are complicating yourself, because you will have to use a multiplexer, you need need powerlines, you'll need resistors and so on... While when using a switch (witch might be a bit pricey), you need just that and the in and outputs.
The switching itself is easier as well... You don't need to remember the whole binary-code where you where at... but just rotate one click.

And I think you won't need buffering if you only use it to do the tuning a you described. Because you will never have two points that will interfere with each other, because basicly a switch is just a connection the same as if you would use a patch cable, and switched/replugged the output of that.

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Re: Eurorack rotary switch module - 8 in 1 out

Post by devinw1 » Thu Jun 25, 2020 12:13 pm

Just saw your thread after replying to your email :D.

Anyway, I agree the rotary switch is probably the way to go. Even if you wanted to switch the signals "off the panel" meaning using a switch ICs, the easiest way would probably be to use a rotary switch to control the switching.

BTW what you are describing with the 3 binary numbers is exactly how a 8 (or n) channel multiplexer handles the addressing. The control lines for say a 8 channel MUX are A0-A2 and depending on which control lines are high, the signal is routed through the corresponding port to the common port. For a 16 channel MUX you have 4 address lines instead of 3, and so on.

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Re: Eurorack rotary switch module - 8 in 1 out

Post by KSS » Thu Jun 25, 2020 8:21 pm

CD4051
For how to use it, see CGS 28 sequential switch module and schematic.

Or just go with the Rotary switch.

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Re: Eurorack rotary switch module - 8 in 1 out

Post by nigel » Thu Jun 25, 2020 8:27 pm

BartBral wrote:
Thu Jun 25, 2020 10:39 am
Personally I would just stick to a rotary switch. Because that is the most simple approach. Otherwise (with the 3 switches) you are complicating yourself, because you will have to use a multiplexer, you need need powerlines, you'll need resistors and so on... While when using a switch (witch might be a bit pricey), you need just that and the in and outputs.
You could do a passive circuit with just three toggle switches, but one of them would need to be a 4PDT. A rotary switch is much easier.

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Re: Eurorack rotary switch module - 8 in 1 out

Post by groffcole » Sat Jun 27, 2020 10:45 pm

I think this solution might work pretty well:
- 2 of these switches: https://www.tindie.com/products/pmfound ... h-pcb-set/
- 1 of these toggles: https://www.tindie.com/products/pmfound ... e-pcb-set/

I can feed all 8 vcos into the two switches and then toggle between the two switches which will be connected to a tuner of some sort.

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Re: Eurorack rotary switch module - 8 in 1 out

Post by authorless » Sun Jun 28, 2020 8:07 am

dubonaire wrote:
Thu Jun 25, 2020 12:42 am
Doepfer A-152
Also Doepfer A-154/A-155 combo.
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