Ufaders

    The 24 input, and 8 output, quadrent faders were all made my Painton (of Northampton, UK). (Elcom, again of Northampton, also used to made a similar type of fader. These we used in our first desk in Chelsea. They were cheaper than Painton, but most customers insisted that we supplied Painton.)
    The essential characteristic of these faders (potentiometers) was that they presented a constant impedance (both in and out) of 600 ohms. Transformers need to always see a constant impedance.
    The picture above shows two versions. The earlier model on the right has beryllium studs, each stud representing a fader position of (precise) attenuation. The picture on the left has a PCB with the fader positions just being pads on the PCB. The sliding arm still has beryllium studs moving across the PCB pads. In use, the pads don't seem to have worn.
    In the top left and right, just under the curved perspex bezel, are two LES 12V lamps - now all broken. One was red, the other green. They were used in boradcast applications for cueing artistes. These will be replaced by LEDs.
    Note (in the bigger version) that the gold on the 15 way edge connector, again made by Painton, has corroded. Also, the rust on the steel locator pins.
    If you listen to 1Khz tone via one of these faders, you hear a click as the arm is moved. This is because there is a definate step between each fader position because of the studs. This can sometimes be a problem with bass instruments. We experienced few promlems as all faders were fed from transformers - hence no DC could be present.