Inline Attenuators

When patching to CV inputs on Ciat-Lonbarde instruments (Cocoquantus, Plumbutter, Sidrax) it can be useful to add some attenuating ability.  For example, if I want to control the frequency of a Sidrax oscillator from a Castle output of Cocoquantus, I want to vary the depth of modulation.  There’s no attenuator on the CV input.  Hence:  Inline Attenuator in a small box with two banana jacks.

inline-attn-front

inline-attn-back

The little box comes from Small Bear Electronics, part number 1090NS.

This is not a potentiometer, i.e. there is no ground connection.  It is simply an inline variable resistor.  It also works well for patching a CV coming out of the modular into a Ciat-Lonbarde instrument.  The CV inputs on Ciat-Lonbarde are very high impedance (often 1M ohms).  And they expect a relatively high output impedance (10K ohms) to drive them.  If you patch a very low impedance CV (like the 1K standard for modulars) or a pot with a grounded end, the current is pulled down so much that control can be ineffective.  So here I have used a 1M audio taper pot as a series resistor.  It can go down to zero resistance.  It’s wired so that as the knob is turned clockwise, the resistance decreases.  Full anti-clockwise does not shut off the CV, but only maximizes the inline resistance to 1M.

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