500 Series Ladder Filter

The Ladder - Moog Music’s first 500 series module!

"That thing is endlessly deep. You could use it on about every instrument to make it more interesting or give it it’s own character… I could play with it for days"  -Michael Wagener

"Its a really powerful tone shaping tool. While I thought I would be using it like one would use a filter in a modular synth, I found more varied positions for it to play as an EQ and subharmonic helper.  It's great for helping anemic drums explode, creating dub bass sounds and modern guitar textures.  Pretty awesome and a great companion to my old Moog 3 band Parametric EQ!"  -Ryan Hewitt

"The Moog Ladder filters manage to marry the tone and tactile advantage of analog hardware with the flexibility of plugins. They have immediately become indispensable tools for shaping my sounds on the way to the DAW." -Fabrice Dupont


The Ladder is a Dynamic Transistor Ladder Filter that is based on Bob Moog's original ladder filter designs. Don't be fooled by its small size, The Ladder is a powerful and fantastic sound sculpting tool that allows for creative and unique sound shifting and shaping. By design, The Ladder sports the smoothest all analog Low Pass and High Pass filter section. Simply adjust the Cutoff knob to add vibe, warmth or tonal adjustment.  Choose LP to add analog vibe and warmth to a sound or select HP for sweetening and relieving the heft of a sound.

 The Envelope section of The Ladder is where things get really cool:

 -       Variable Attack and Release controls allow you to perfectly dial in the behavior of The Ladder's envelope section. Use these controls to open and close the envelope as fast as lightning, or slow as molasses.

 -       Use the Amount control in Positive or Negative mode for mild to extreme sound shaping and manipulation. From slight timbral excitement and voicing to extreme compression-like behavior. Even reversed filter action is achievable!

 -       The Resonance control used with The Ladder’s other features allows for the creation of sweet, dynamic and even speech like behavior. Use it to tune The Ladder to a sound source… or not. You can excite or accentuate specific frequencies as well as create completely new unique and wild sounds.

NOTE: The Ladder's Resonance control will push the unit into self-oscillation. This can be used for effect if desired.

The 2Pole/4Pole switch allows you to select how aggressive your filter slope is. 2 pole is equal to 12db per octave which is smooth and sweet, while 4 pole is 24db per octave which is hard and aggressive.

You also have a hard wire Bypass for totally transparent routing and A/B comparison

The Ladder isn't your average filter. It's a big step up


Audio I/O: Balanced line level via 500 rack. +19dBµ to -16dBµ input accepted.
Filter Type: 2 and 4 pole dynamic low-pass & high-pass transistor Ladder Filter
Envelope Type: RMS detector, bi-polar with variable attack & release
Attack time:    Better than 250µS to 2.0 seconds depending on program material and level.
Release time:  Better than 150mS to 2.0S depending on program material and level.
Envelope Control: Positive and Negative Modulation
Input Impedance: Nominally 24KΩ balanced differential, 12KΩ unbalanced single ended.
Output Impedance: Nominally 50Ω  differential 25Ω single ended.
Max. Output Level: Better than +22dBµ, balanced.
Drive Gain: 36dB Range of control
Output Gain: 36dB Range of control
Frequency Response: Better than +/-0.5dB 20Hz – 20KHz pass band.  Better than +/- 1.5dB 5Hz – 24KHz pass band.
Bypass: Hard Relay True Bypass
Power Consumption: Less than 105mA +16V, less than 75mA -16V.


*Specifications subject to change without notice

500 Series Ladder Filter

Synths With The 500 Series Ladder Filter

500 Series Ladder Filter (Electronic Drums)

500 Series Ladder Filter (Acoustic Drums)

Category Name Added Format Description Download Link
Manual The Ladder Manual 2012-01-30 PDF Ladder_Manual.pdf
Introducing the Ladder
See video
Michael Wagener on The Ladder
See video
Ben Lindell on the Moog 500 Series Ladder Filter
See video

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