• Wish list
  • Choose your store
    All countries
  • 0

5. Pedal Action

Both the Vox and Crybaby pedals use a mechanical system called ‘rack and pinion’. The linear motion of the pedal is translated to rotary motion, as shown in the diagram. This in turn rotates an ordinary potentiometer (variable resistor) which is connected to the filter electronics, thereby affording control of the wah effect.

Rack and Pinion

This is a very popular system and is used by many wah pedals, both vintage and contemporary. It does however have a well-known disadvantage - general purpose potentiometers were never designed to work in this repetitive manner, and with constant movement, the internal carbon tracks wear down and become uneven. This can introduce a scratching noise when the pedal is operated. In fact the ‘pot’ can degrade over time even if the pedal is not used for a while, as the track is liable to oxidization and the oxide is non-conductive. With models based on this principle, the only solution is to replace the pot if and when the problem arises. It should be noted though that some players favour the ‘grit’ of a slightly worn track as it can lend an edge to the sound. Unfortunately, just like a valve amp or a worn plectrum, it will only be at its subjective prime for a limited time! Some modern replacement pots use a conductive plastic track instead, which is far more resilient.

Replacement potentiometer

In an attempt to overcome the wear-and-tear problem, some manufacturers introduced new techniques. Morley developed their ‘electro-optical’ system, which is currently employed in all varieties of their wah pedals. The light from an LED (light emitting diode) shines onto an LDR (light dependant resistor). These two components are separated by a small gap, and a shutter-strip connected to the pedal is placed between them. The strip is transparent at one end and opaque at the other, with a continuous change from clear to dark along its length. As the pedal is moved, a varying intensity of light falls on the LDR, which in turn controls the wah filter. This unique design with only one moving part ensures smooth control, without the inevitable unwanted noise that is typical of potentiometer designs. Some other manufacturers now also employ the optical approach in one form or another.

Electro-Optical

An alternative technique, which isn’t seen so much these days, is based on the so-called ‘Hall-effect’. A small magnet is secured to the underside at the ‘toe’ of the pedal. As the pedal is moved forward, a Hall-effect device - whose electrical characteristics change smoothly with the increasing proximity of a magnetic field - detects the change in position and controls the wah filter proportionately.

Hall-Effect

Either approach renders the unit completely maintenance-free, which is certainly worth bearing in mind.

Your Contact People
Phone: +49-9546-9223-20
FAX: +49-9546-9223-24
Get Your Free Copy of our Hot Deals Catalogue!

More than 7.900.000 musicians are avid readers of Thomann's Hot Deals catalogue. Get your free copy now! More than 500 current offers!

Hot Deals
Question!
Question! Give the right answer and win 1x the t.bone SC 440 USB worth 58 €.
What instrument is powered by steam?
Conditions of participation
Terms and Conditions for participation
in online competitions

Note: Participation in an online competition runs independently from any purchase at Thomann GmbH. The following Competition Rules apply when participating in any online competition run by Musikhaus Thomann:

  1. Competition

    1. The competitions are organised by Thomann GmbH, CEO: Hans Thomann, Hans-Thomann-Straße 1, 96138 Burgebrach, Germany.
  2. Participation

    1. Competitions are only open to persons of full age.
    2. To take part in the competition you must answer all questions correctly, fill in the registration form and submit your entry to Thomann GmbH by pressing the "send" button.
      By pressing the "send" button the participant accepts the aforementioned terms and conditions.
    3. The participant is responsible for entering their email and/or postal address correctly. Entries to the competition will be logged electronically.
  3. Qualifying Entrants

    1. Staff of Thomann GmbH and any cooperation partners and their dependants are excluded from participation.
    2. Should these conditions of participation be violated, especially by using illegitimate means, Thomann GmbH reserves the right to exclude persons from the competition. In case of such violations prizes can be withdrawn and claimed back subsequently.
  4. Announcing the winner

    1. The winners will be notified by Thomann GmbH by email or in writing and their names may be published on the homepage www.thomann.de. The winner accepts this form of publication explicitly.
      Should for whatever reason the winner not claim their prize, then a new winner will be drawn.
    2. The prize presented to the winner may not be identical to the item description. There can be deviances regarding the model, colour etc.
    3. The merchandise prizes will be sent by Thomann GmbH or by one of its contracting delivery companies, per freight forwarder, courier or postal service to the postal address indicated by the winner.

      The delivery is free of charge. Only extra transport costs and customs/duties must be covered by the winner. In the case that the delivery has to be made through a freight forwarding company the freight forwarding company will contact the winner to arrange delivery timings.
    4. An exchange, cash alternative or replacement prize is not possible.
    5. The claim to the prize or replacement of the prize cannot be assigned to a third party.
  5. Data protection

    1. The participant accepts explicitly that Thomann GmbH saves all necessary data for the duration of the competition and forwards them exclusively for purposes related to the winning process to the respective cooperation partner, who is also permitted to save the personal data only for the duration of the competition. The participant is free to withdraw his entry at any time. Please direct the withdrawal to:

      Thomann GmbH
      to the data protection officer
      Hans-Thomann-Straße 1
      96138 Burgebrach, Germany
    2. Thomann GmbH is obliged to consider the regulations for data protection according to the Federal Data Protection Law (BDSG) valid at the conclusion of the competition. In this context the general data protection regulations under notes regarding data protection should be noted.
  6. Liability

    1. Thomann GmbH will be released from any obligations by handing out the prize.
    2. Thomann GmbH is not liable for the insolvency of a cooperation partner and the resulting consequences for the implementation and processing of the competition.
  7. Other

    1. Legal proceedings are barred.
    2. The law of the Federal Republic of Germany applies exclusively.
One of our Fan
Always satisfied with Thomann!
bilxxxs@yaxxx.fr, 16.02.2017

Wah Pedals overview

(14)
(1)
(3)
(1)
(2)
Feedback

Found an error or want to give us feedback about this page?

We're looking forward to hearing from you and aim to solve any problems as soon as we can.

cancel