The mk4 builds on the previous mk3 and adds these new features:
- a dot matrix display, making menu navigation, parameter selection etc. a breeze.
- a front panel accessible MicroSD card slot.
- compatibility with the Macro Machines Storage Strip.
- an internal precision clock allowing new algorithms such as a tuner, and pitch and frequency references.

The new version is largely software-compatible with the mk3, and the intention is to continue releasing new features for both the mk3 and mk4 in parallel.

X & Y inputs, A & B outputs:

• ADC: 24 bit, THD+N -93dB, Dynamic range 99dB, SNR 99dB
• DAC: 24 bit, THD+N -94dB, Dynamic range 105dB, SNR 104dB 
• Sample rate: 75kHz
• Z input sample rate: 75kHz

CPU: Microchip PIC32MX at up to 50MHz, hackable, open source code framework available.

Functions
There are currently 5 'banks' of algorithms. The first 16 ('classic disting') are:

• Precision Adder with integer voltage offsets
• Four Quadrant Multiplier with integer multiply/divide
• Full-wave Rectifier
• Minimum/maximum
• Linear/Exponential Converter
• Comparator with adjustable hysteresis
• Sample and Hold with noise source and adjustable slew rate
• Slew Rate Limiter with linear and exponential slew
• Quantizer with selectable scales
• Pitch and Envelope Tracker
• Dual Waveshaper - wavefolder and triangle-to-sine shaper
• Clockable Delay/Echo
• LFO with through zero frequency control and waveshaping
• Clockable LFO with multiply/divide and waveshaping
• VCO with linear FM sine and saw outputs
• VCO with waveshaping (saw/triangle and pulse outputs)

The second bank contains: 

• Precision Adder with fractional voltage offsets
• Resonator for drum synthesis
• LP/HP Filter 
• LP/BP Filter
• BP/HP Filter
• BP/Notch Filter
• State Variable Filter (smoothly variable filter type)
• Voltage Controlled Delay Line (vibrato/chorus/flange effects)
• Tape Delay with voltage controlled tape speed 
• Clockable Ping Pong Delay (with or without with input pan control)
• Vocoder (12 band)
• Phaser (up to 10 stages)
• Bit Crusher

The third bank contains:

• Single and Dual AR Envelopes (with or without push)
• AR Envelope & VCA (with or without push)
• Clockable AD Envelope (with mute, gate or trigger) 
• Clockable AD Envelope & VCA
• Shift Register Random CVs
• Shift Register Random Quantized CVs
• Shift Register Random Triggers (single or dual)

The fourth and fifth banks contain:

• ES-1 and ES-2 Emulation
• Pitch Reference
• Frequency Reference
• Tuner
• Crossfade/Pan
• Audio Playback (16 bit WAV, mono or stereo)
• Clocked Audio Playback
• Audio Playback with V/Oct, Z Speed or End CV 
• MIDI File Playback (Clocked or Free Running)

• 4hp
• 51 mA +12V
• 19 mA -12V
• 0 mA 5V
• 42 mm deep