Zoë Blade's notebook

Behringer 900 Series

900 Series tech specs

Behringer released the 900 Series in 2020. These modules are clones of the Moog modular synthesisers, and as such have been nicknamed Boog by some fans. As with other Behringer clones of the era, they're conveniently shrunken down to Eurorack format.

The general consensus seems to be that it sounds like a Moog modular, but doesn't act like one. Recommended modifications include replacing the rather erratic pots with more consistent ones that allow smooth operation,[1][2][3] and replicating the original's trunk lines (multiple CV and gate busses) to reduce the need for micromanaging connections.[4] There's also a rather nice 904A mod that makes it sound like a 1967-era original.[5]

The main thing to watch out for is calibrating the oscillators. They're not temperature compensated, so they drift as they warm up — not just their offset, but also their range.[6] At time of writing, Nina and myself just spent several hours getting them spot on outside of the case, and now that they're back in the case, their ranges are all perfectly off by the exact same amount.


Model Type HP Description
902 Module 8 VCA
903A Module 4 White and pink noise
904A Module 8 Lowpass VCF
904B Module 8 Highpass VCF
911 Module 8 ADSR envelope generator
911A Module 8 Dual trigger delay
914 Module 28 Extended range fixed filter bank (12 bandpass, 1 low, 1 high)
921 Module 14 VCO (Doubles as LFO)
921A Module 8 Oscillator controller
921B Module 8 Oscillator
923 Module 8 Highpass and lowpass filters / White and pink noise
960 Module 56 Sequential controller
961 Module 21 Interface
962 Module 8 Sequential switch
992 Module 8 Control voltages / attenuator
994 Module 4 Multiples
995 Module 8 Attenuators
CM1A Module 6 MIDI to CV converter
CP1A Module 4 Power supply
CP3A-M Module 14 Mixer / multiples
CP3A-O Module 8 Front trunklines / attenuator
CP35 Module 21 Attenuators / dual CV sources / multiples


  1. Re: Behringer System 55 SkyWriter, Oct 2020
  2. Re: Behringer System 55 SkyWriter, Oct 2020
  3. Re: Behringer System 55 SkyWriter, Oct 2020
  4. Moog Modular Routing Rob Keeble, Dec 2021
  5. Behringer 904A Rewinds to 1967 Rob Keeble, Nov 2020
  6. Re: Behringer System 55 BowserB61, Sep 2020




Modular synthesisers: Behringer 100 Series | Behringer 900 Series | Doepfer A-100 | Moog Modular | Roland System-100M