Damper&Expression Pedal Guide
This dossier explains the function of Sustain, Expression and Volume Pedals .
Sustain (Damper) Pedals
A Sustain (or ‘Damper’) Pedal has a simple on/off switch, keyboards are designed to respond to the switch being open or closed and sustain the sound while the pedal is pressed. Unfortunately there is no single common standard and using a switch of the wrong type may mean the keyboard doesn’t respond as expected (sustaining when pedal not depressed and releasing when it is).
There are basically 3 types of switches : Normally Open (NO), Normally Closed (NC) and Universal as shown below. (Note: Half Damper pedals not covered as Roland VR doesn’t provide this function)
|In a normally open (NO) pedal, in the pedal up state the switch is open (off), pressing the pedal closes the switch and completes the circuit between the two terminals in the plug. A normally closed (NC) pedal works in the opposite way, pedal up it is closed (on), pressing the pedal opens the switch and breaks the circuit between the two terminals in the plug Universal pedals are able to change the action of the pedal to be either NO or NC as required. This is achieved by using either a dual pole or two individual switches with a selector switch to chose how it works.|
The Roland VR needs a normally closed (NC)pedal, i.e. opens (or switches off) when you press it. Using a normally open pedal will make the VR sustain when the pedal isn’t pressed and stop sustaining when you press the pedal. It is the type of the switch inside the pedal that is critical and not the wiring within the jack plug or cable, it’s not polarity, changing over the wiring will make no difference.
|Typical universal pedal with 2 individual pedal switches|
Universal switch is a good choice as it will work with any keyboard as long as it’s adjuster switch is set the right way – normally closed for the Roland VR.Some keyboards are able to auto detect the state of the pedal when powering up and work accordingly so can be used with either NO or NC pedals, this is why you should never press any pedals when powering on a keyboard. However, the Roland VR does not auto detect – you must use the right type of pedal.
Expression pedals are used to control the volume of a keyboard – and, in the case of ‘organ’, also act like an organ swell pedal: the more the volume increases the more ‘tube saturation’ of the internal overdrive is added (see below, expression vs. volume pedal)Expression pedals or to give them their correct name Continuous Controller (CC) pedals have a variable resistor (potentiometer) linked to the pedal. A reference voltage is sent from the keyboard and the position of the pedal determines the voltage returned to the keyboard. This is then converted by electronic trickery to a MIDI control message which the keyboard uses to control whatever parameter is assigned to it – usually Expression but depending on the capabilities of the keyboard could be one or more of many things.Connection is (usually) via a stereo (TRS) cable and the way this is wired is important.
|TRS compatible pedal
For most instruments the reference voltage is sent via the ring connection and the control signal returned by the tip connection. The sleeve completes the circuit as ground connection.
RTS compatible pedal
The alternative arrangement is for the reference voltage to be sent via the tip connection and the control signal returned by the ring connection. Again the sleeve completes the circuit as ground connection.
Many of todays Expression Pedals have a ‘polarity inverter’ switch to change between TRS and RTS
The arrangement (or polarity) matters, wired the wrong way it will not work. On pedals without ‘polarity inverter switch’ it is possible to change the polarity of an expression pedal from RTS to TRS (or vice-versa), either:
- Open up the pedal and change over the wiring by switching tip and ring connections at the socket or cable
- Buy (or make) an adapter cable with the wiring reversed at one end
- Buy a custom made adapter
- Use (easy) two stereo to twin mono splitter cables and connect as below
|To use two splitter cables, connect red to white and white to red to switch the polarity. Connecting red to red and white to white allows it to be used as a normal stereo cable.|
Other than Expression Pedals, which regulate the internal volume setting of the keyboard, Volume Pedals are added into the AUDIO SIGNAL PATH after the keyboard line-outs, reducing the voltage of the VR audio signal before it enters the mixer (PA, etc.).
Volume vs. Expression Pedals
For a Hammond-Clone like the VR, the difference between Expression and Volume Pedals is fundamental:
|Expression Pedals modify the keyboard volume and push the internal (organ) overdrive into saturation
Volume Pedals modify the keyboard volume but leave the amount of of internal overdrive unchanged
When using an EXTERNAL Leslie-Sim with ‘Overdrive’ (like Ventilator, Lester-K etc) or even a real Leslie, Volume Pedals behave like the Expression Pedals and push the overdrive
Roland VR needs:
- Sustain pedal – Normally Closed (NC) or Universal set to NC
- Expression pedal – Wired TRS or with “polarity inverter switch”. Any resistance 10kOhm, 20kOhm, 50kOhm, … will work (or rather ‘not work’: see below….)
If you wonder why your expression pedal reacts like an ‘on-off’ switch: VR09/730 have a wrongly calibrated voltage detection of expression pedals. This is the “VR expression pedal bug” and involves ALL types of pedals. You can solve this by modifying your pedal: Expression Pedal Mod
For a list of recommended sustain and expression pedals, see GEAR
To fix the ‘VR expression pedal bug’, see