Dave Smith Instruments Mopho x4 (2013–2018)

Name: Sequential Circuits Mopho x4
Brand: Sequential Circuits

A 4-voice analog synthesizer with 44-key semi-weighted keyboard, produced from 2013 to 2018

Overview

The Dave Smith Instruments Mopho x4 is a polyphonic analog synthesizer with four voices and a 44-key semi-weighted keyboard. The signal path is 100% analog, and it works for both studio and live use. Each voice has two analog oscillators and two sub-octave generators, which makes for a thick sound. It was introduced in 2012, officially produced from 2013 to 2018, and then discontinued.

Specifications

Polyphony	4-voice
Oscillators	2 analog oscillators per voice, 2 sub-octave generators per voice
Filter	Lowpass filter
Envelopes	3 x 5-stage envelope generators
LFOs	4 LFOs
Arpeggiator	Relatchable arpeggiator
Keyboard	44-key semi-weighted
Signal Path	100% analog
Dimensions (W×D×H)	640 mm × 282 mm × 91 mm (25.2″ × 11.1″ × 3.6″)
Weight	6.2 kg (13.5 lbs)
Original Price	C$1,399.99
Production Years	2013–2018

Design

The Mopho x4 comes from earlier Dave Smith Instruments models including the Mopho, Tetra, and Prophet '08, and shares design and synthesis architecture with them across the line. The signal path is fully analog, with the oscillators and filter in the lower-right section of the panel. It is known for oscillator and filter bleed, which gives it a characteristic analog warmth. Some users note that the filter does not completely close.

Context

The Mopho x4 was introduced in August 2012 and produced through 2018. It filled a niche as an affordable, compact polyphonic analog synth with professional-grade sound. It was positioned as a performance and studio instrument, and it was praised for durability, sound quality, and value. The model was discontinued by 2019.

Market

The Mopho x4 has been listed at prices around $600 in standard market tiers, with earlier listings showing $690 in 2013. Units in excellent condition are reported to work perfectly. Some users have noted the filter's inability to fully close as a known behavior. Replacement parts and service information remain limited.