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ANATOMY OF AN EXPRESSION CONNECTION

NOTE: This is explicitly for Ramble FX pedals, but it is also the most common configuration for other pedals. Check the manufacturer's specification first.

 

Kismet’s expression input is a ¼” TRS, or stereo jack. TRS stands for TIP, RING, SLEEVE, and describes the three connections of the plug. Kismet sends a constant 5 volts out through the RING connection and measures the voltage that returns on the TIP connection. That voltage is corresponds to the expression pedal's position.

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Constant 5 volts is supplied by Kismet (or other pedal)

A voltage is returned (0-5V) that corresponds to the expression pedal's position.

Ground

DO NOT inset a TS mono connector into the expression jack

Expression input is for PASSIVE devices only. All devices NOT powered, like most volume and expression pedals, are passive. If it requires a power connection for gain, buffer, etc., it is NOT compatible. A specific exception is a pedal that uses power only to vary internal resistances via an opto-coupler and has an entirely passive signal path (some Morley pedals). For control voltage (CV) device instructions, go HERE

CONNECTING A VOLUME PEDAL FOR EXPRESSION CONTROL

A volume pedal is a foot-controlled potentiometer with separate input and output connections. A voltage enters one jack and a fraction of that voltage is sent out the other jack. It usually has a logarithmic (audio) curve, or sweep. Most volume pedals can be used as an expression controller, but a special cable, such as the HOSA STP-203, is required.

POTENTIOMETER

INPUT

OUTPUT

INTO KISMET'S (or other compatible pedal) EXPRESSION INPUT

STEREO -to- DUAL MONO CABLE

HOSA STP-203 or similar

CONNECTING AN EXPRESSION PEDAL

An expression pedal is a foot-controlled potentiometer with only one stereo jack. A single cable contains both the input and the output wires. A fixed voltage enters on one wire, and a fraction of that voltage is sent back on a separate wire. The taper, or sweep of most expression pedals is linear. Most expression pedals can be used with Kismet.

POTENTIOMETER

NOT POWERED

REQUIRED: TIP-to-WIPER POLARITY

REQUIRED CONNECTION POLARITY:  Tip-to-wiper. This is probably the most common, but not all pedals use this polarity. Expression pedals with the wrong polarity can be made compatible with a polarity-reversing adapter, available at here. 

COMMON EXPRESSION PEDALS

This is a chart of the polarity and sweep of some common expression pedals. All are directly compatible with Kismet except for the Zoom FP02M, which requires the "1/4" Stereo Polarity Changing Adapter," available from Ramble FX, and shown above. Kismet's "Expression Sweep" toggle switch should be set to match the "SWEEP (taper)" of the expression pedal.

PEDAL

Moog EP-3/EP-2


Zoom FP02M


Dunlop DVP4 Mini/DVP3


EHX Expression


M-Audio EX-P

 

NOTE:  Line 6 pedals that use a TS, mono cable are not compatible.

POLARITY

Correct with switch set to 'OTHER'

Wrong. Correct if used with “Polarity reversing adapter” (buy at www.ramblefx.com)

Correct with switch set to TIP


Correct with TRE +/- Button 'out'
 


Correct with switch set to ‘M-Audio’

SWEEP (taper)

Log (audio) - must have knob turned all up

Linear



Linear - set minimum knob to fully counter clockwise

Linear - set range to '10'


Linear

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