[sdiy] Buchla 257 is an extremely strange circuit

[Jerry Gray-Eskue]

<<That makes "joystick-centre" silent!>> no...
<<"centre = 33%">>

The center = 33% is correct.
Assuming the level of the three signals are the same and ignoring phase
cancellation the output level is approximately constant.

- Jerry


-----Original Message-----
From: Needham, Alan [mailto:Alan.Needham at centrica.com]
Sent: Wednesday, December 16, 2009 9:45 AM
To: Jerry Gray-Eskue; Synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Buchla 257 is an extremely strange circuit


That makes "joystick-centre" silent!
I follow the three sliders, just make them "centre = 33%"
I wonder if light beams would be better, given that there will be some
side-loading as you move the joystick at 90 degrees to the slider's
travel?


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Jerry
Gray-Eskue
Sent: 16 December 2009 14:03
To: Synth-diy at dropmix.xs4all.nl
Subject: RE: [sdiy] Buchla 257 is an extremely strange circuit

A second thought if you do not like the resistive triangle..

Use three slide pots arranged as the triangle with signals on the points
and
ground in the center.
Add a plate with 3 slots at 90 degrees to each slide travel with the
matching wiper through each slot.
Add a central control knob to the plate and allow free movement of the
plate
but prevent rotation.

- Jerry

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