Beers 2P4T Analogue Switch

Beers 2P4T Analogue Switch

2-pole 4-throw binary-addressed bidirectional analogue switch.

Loosely intended to mimic the functionality of the 4052 CMOS multiplexor/switch IC but each channel can be individually addressed (yay!) and there is no inhibit function (boo!).

XA, XB, YA, and YB are the control inputs and any signal patched to them that crosses approx. 0.5V will be converted to a 2-bit binary word and decoded into one of 4 positions for each switch.

The control inputs XA and XB will control both switches at once with nothing plugged into YA and YB.

I initially looked into using solid state relays or dedicated switch ICs to achieve this design (would have been nice) but instead went with a cheaper discrete MOSFET switch circuit using parts I already had loads of.

Caveats:

It can cleanly switch eurorack signals at ±10V or more, although as the input signal/s approach the power rails they may be clipped at 10.5-11V or so, and 'off' legs of the switch may leak/be forced on.

You may observe a 'click' or switching artifact when using the COM jack as an output and a throw with nothing patched in is selected. If this bothers you try patching unused inputs to a source of 0V in your system, or use the common jack as in input instead.

The switches have an effective 'on' resistance of approx. 1kohm. This can be lowered at your own risk by replacing the 470R resistors with something much lower (10R?) or direct shorts.

While the 3P2T version of this analogue switch was already on my list of unfinished ideas, I have Richard Brewster to thank for getting in touch to ask about a 4052 module. Gave me an excuse to get both done!

6HP +12V: 10mA -12V: 7mA

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On Demand Info

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