The Moon Modular M 504 is a 24dB Transistor Ladder Filter that’s inspired by the classic Moog 904A filter, an iconic sounding circuit which defined the sound of early R.A. Moog modular systems.

Moons M504 provides three distinct switchable slopes at 12/18 and 24dB per octave, with full voltage control over the cut-off frequency and also rather uniquely, the regeneration (resonance).

At high regeneration settings, this filter will self oscillate, creating a very usable sine wave tone, which can be placed under voltage control and used a sound source if desired.

Dual frequency control inputs means that if your envelope doesn’t have an amplitude control, you can adjust the amount of envelope control at input one using the provided attenuator, or apply an audio rate source at input once and get amplitude control over FM of the filter cut off…pretty handy.

 This is an iconic, classic, tradition circuit that has been incredibly well implemented in Moons ecosystem, giving you the classic tone of a 904a in a slimmer single module space.

The main features of the Moon Modular M504 Transistor Ladder Filter include:

• Classic RA Moog inspired 24dB transistor ladder filter
• Three distinct response curves at 12,18 and 24dB slopes
• Single MU unit wide
• .com power connector