The MOTM-485 is a recreation of the Yamaha GX-1 LP/HP filter.

The GX-1 was a massive organ/synth hybrid, costing over $60,000 in the late 1970s. The best example is the Emerson, Lake, & Palmer song "Pirates," but the GX-1 was was also used by Stevie Wonder and Led Zepplin.

The GX-1 used a pair of these filters to form a bandpass response (the same method used in the MS-20 and the CS-80). There is a HP filter set to "half tracking" followed by a LP at "full" tracking. However, you can still use a single MOTM-485 as yet another distinct tone in your setup, or use two to recreate the exact sound of the GX-1.

  • Two audio inputs
  • Voltage-controlled frequency and resonance
  • Switchable HP/LP response
  • Switchable half/full tracking of the 1V/Oct input
  • Fully temperature-compensated using TEMPCO resistor and matched pairs
  • Not a "clean" filter, has higher distortion than other MOTM filters due to the GX-1 design