Author Topic: Leslie 60 aux outputs - impedance and voltage levels?  (Read 53 times)

Offline pgroff

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Leslie 60 aux outputs - impedance and voltage levels?
« on: February 24, 2017, 09:55:52 AM »
Hi all,

I only have very rudimentary electronics knowledge. I'm hoping one of the audio experts here can help me with a question about the Leslie 60 speaker system that was sold in the 1970s to amplify Wurlitzer and Rhodes pianos. They're somewhat comparable to the Rhodes satellite system - 2 speakers with a vibrato. But the Leslie 60 uses a "space generator" system of motor-driven variable capacitor plates.

The Leslie 60 system (60M, 60S, and controller) is designed to (optionally) also send signal to two auxillary speakers.  The controller box (designed to mount on the piano and housing volume and vibrato controls) has a male 1/4" phone plug to connect with the piano, then send the signal to the  60M (main) speaker cabinet via a 5-pin  Leslie cable. The 60M speaker cabinet includes the power supply, space generator, two power amps, and one 10" speaker. The 60S (satellite) speaker cabinet includes one unpowered 10" speaker, fed by one of the amps in the 60M.  However the 60M also has 2 auxilliary outputs for main and satellite powered speakers.  See p. 4 of the manual, linked here:
https://www.musifix.nl/Web-data/Technical%20Docs/Leslie%20Model%2060%20en%2070.pdf

Looking at the schematic for the 60 M power amps, the auxilliary outputs seem to be taken from the speaker outputs and attenuated by a simple resistor network. But I don't know enough about such circuits to guess the impedance and level of those aux outputs. See page 27 of that manual, linked here:
https://www.musifix.nl/Web-data/Technical%20Docs/Leslie%20Model%2060%20en%2070.pdf

My question is: What is the impedance and the voltage level of those auxilliary outputs on the 60M?  Are they at instrument levels (to run into the input of a Princeton for example) or line level (to run directly into a power amp)?  I can't find any clear guidance in the manual and I don't want to blow anything up.

Thanks if any of you can help, from your experience with these circuits.

Paul Groff
« Last Edit: February 25, 2017, 05:35:30 AM by pgroff »