Roland EV-5 pedal

Don Tillman don at till.com
Sun Apr 4 21:27:28 CEST 1999


Now *this* is a good place for a little standardization. :-)

High impedance ("guitar") volume pedals are 250k-500k audio or
linear taper pots and are intended to go between an electric guitar
and amp, where they work well.  They do not work well going into a
medium input impedance (10k to 50k) like a line-level mixer input.
They may or may not work as control voltage pedals, depending on the
circuit details.

Medium impedance ("keyboard") volume pedals are roughly 25k or 50k
audio or linear taper pots and are intended to go between a preamp
level signal and a mixer input.

Control voltage ("expression") pedals can be resistance based (like
the ARP pedals, 100k audio taper) or pot based (Yamaha FC-7) or other
variations.

All the Roland volume pedals I've seen have been very low quality.
Brittle plastic, cheap pots and connectors.  I once saw one die within
the first hour of use.

The Yamaha FC-7 is pretty nice.  Medium impedance, 50k linear.  As
others have said, it's wired as a potentiometer, tip in, ring out.

(Mellotron players know that Mellotrons have two output jacks, one in
the front and one in the rear of the instrument, and the signal goes
to the front output wired as a shorting stereo jack, and then to the
rear output, so you can use either output jack as an output, but if
you use the rear output jack as an output you can plug a Yamaha FC-7
into the front output jack and it gets inserted into the circuit, and
works beautifully as a volume pedal.  Of course the original Mellotron
volume pedal worked like that, but those tend to get lost.)

The most robust units are easily the Ernie Ball volume pedals; they're
built like tanks and are recently available in medium impedance
models.  (I don't know the pot taper on the medium-impedance models.
Their mono high impedance guitar pedal is audio taper, their stereo
high impedance guitar pedal is linear taper because there's a switch
to reverse one of the pots to make a stereo pan pedal, and that needs
to be symmetrical.)

PaulP: On your EV-5, I'm guessing the reason the voltage doesn't go to
zero is mechanical -- the pedal doesn't travel the full range of the
pot, so if you open up the unit and rotate the pot mounting position a
little you should be able to go to zero.

Keep those pedal suggestions coming; I'm eager to find out if there's
something available that's better than the Yamaha FC-7 for voltage
control. 

  -- Don



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