Expression pedal issue

Pulling out your hair? Don't know what to do or where to go? Ask in here.
Forum rules
READ: VSE Board-Wide Rules and Guidelines

If your Help request has been solved, please edit your first post in order to select the Image Topic Icon to let others know your topic has been solved.
Post Reply
gcoudert
Expert Member
Expert Member
Posts: 1198
Joined: Sat Dec 29, 2007 1:24 pm
Real name: Gilles
Gear: Roland Fantom X7 with Ultimate Keys expansion, Yamaha TX802, Roland JP-8080, Tascam DP-24SD.
Location: SE England

Expression pedal issue

Post by gcoudert » Sun Dec 21, 2014 12:03 pm

I have tried to use my Yamaha volume / expression pedal with my Fantom X8 and, although it does what it is supposed to do, it doesn't return to 0 setting when the pedal is in its 0 position (when assigned to LFO pitch depth, I can still hear vibrato). I have used the pedal for years with no issues with various keyboards from various manufacturers including my very recently-sold Roland Jupiter 50. I have no other keyboard to test it with but I think the Fantom calibration may be to blame. However, there is no controller calibration function (as there was in my E-mu E4K). Any ideas?
GC

db0451
Junior Member
Junior Member
Posts: 147
Joined: Thu May 08, 2014 12:06 am

Re: Expression pedal issue

Post by db0451 » Sun Dec 21, 2014 12:59 pm

I assume you have ensured the affected voice(s) do not have vibrato programmed ‘natively’, i.e. before any controller increase?

If that is not the cause, then I am pretty sure that neither the pedal nor the synth will offer calibration. Being from two different companies, they probably would just say to buy their own controller and not approve compatibility with other manufacturers. The synth will just expect a certain range of voltages/currents from its ‘official’ pedal.

Be warned that some types of pedals can actually short the PSUs of some (not officially compatible) synths and put the main circuitry at risk. I think that results from bad design by the manufacturer of the synth, but it is worth being extra careful anyway.

gcoudert
Expert Member
Expert Member
Posts: 1198
Joined: Sat Dec 29, 2007 1:24 pm
Real name: Gilles
Gear: Roland Fantom X7 with Ultimate Keys expansion, Yamaha TX802, Roland JP-8080, Tascam DP-24SD.
Location: SE England

Re: Expression pedal issue

Post by gcoudert » Sun Dec 21, 2014 1:11 pm

db0451 wrote:I assume you have ensured the affected voice(s) do not have vibrato programmed ‘natively’, i.e. before any controller increase?
Yes, I tested it with 'flat' patches.
db0451 wrote:If that is not the cause, then I am pretty sure that neither the pedal nor the synth will offer calibration. Being from two different companies, they probably would just say to buy their own controller and not approve compatibility with other manufacturers. The synth will just expect a certain range of voltages/currents from its ‘official’ pedal.
I thought so but then it has been working fine with other Roland products I have owned over the years (D50, JP50, D70, etc.) as well my old Korg M1 so I didn't think the X8 would behave different but you may well be right.
GC

User avatar
pricklyrobot
Synth Explorer
Synth Explorer
Posts: 1742
Joined: Sun Feb 19, 2006 6:37 am
Location: Austin, TX

Re: Expression pedal issue

Post by pricklyrobot » Mon Dec 22, 2014 7:18 pm

Unfortunately expression pedal polarity was never standardized. All have a TRS cable attached to a pot (inside the pedal). But some attach the pot's wiper to Tip, while others attach it to Ring. Yamaha and Roland, notably, use opposite schemes. Hence your Yamaha pedal kinda works on your Roland, but the sweep range is off.

If you DIY, you can easily open easily swap the T & R connections, or maybe wire them to a switch for max compatibility.

This page: http://www.marichiba.com/how-to-replace ... yamaha-fc7 has a nice chart of commonly available pedals.

Also, expression pedals are passive and do not generate any voltages, they just attenuate voltages coming from the synth. I can not envision a scenario where an incompatible expression pedal could actually damage a synth.
Arturia MiniBrute -- bits o' Euro -- Sammich SID -- E-mu MP-7 -- Korg ER-1 -- Thingamagoop

User avatar
Tidda
Junior Member
Junior Member
Posts: 154
Joined: Sat Sep 16, 2006 5:30 pm

Re: Expression pedal issue

Post by Tidda » Mon Dec 22, 2014 8:14 pm

I use these two for switching the polarity of my FC-7

Image

Image

db0451
Junior Member
Junior Member
Posts: 147
Joined: Thu May 08, 2014 12:06 am

Re: Expression pedal issue

Post by db0451 » Mon Dec 22, 2014 8:27 pm

pricklyrobot wrote:Also, expression pedals are passive and do not generate any voltages, they just attenuate voltages coming from the synth. I can not envision a scenario where an incompatible expression pedal could actually damage a synth.
It can’t hurt to be cautious; can it?

and OK, it was a case of a mono footswitch being plugged where a stereo expression pedal is expected, but this well-known danger demonstrates how a passive component can risk killing a synth, in this case the Kawai K5000:
Pay attention when plugging in a sustain pedal that you *always* plug
into the HOLD jack and not into EXP. A mono plug inserted into EXP will
short the power supply to the motherboard (synth goes silent if you do
his), and left in there for more than a moment or two and you have fried
the machine--thus requiring a factory repair.
https://groups.yahoo.com/neo/groups/K50 ... pics/12566 and various other/better discussions on this. Yes, shorts are always a bad idea, the circuit shows bad foresight by the manufacturer, and users should be more careful… ;) but it’s still worth bearing in mind.

I thought I also remembered reading about a similar problem caused by differing polarities, but probably I was mistaken, seeing as the simple inversion of range you have described here (where minimum position becomes > 0 V) sounds more plausible.

Post Reply