At 21.25" x 7.43" the desktop module sheds more than ten inches in width and five inches in height when compared to the keyboard version. However, it manages to maintain the same performance controls and internal components as the original, thanks to some thoughtful design choices and judicious use of space. All you lose is the keybed, pitch and modulation wheels, transpose control and the Prophet-6 metal badge, but most MIDI keyboards contain these features, (aside from the badge of course). The same jacks and ports are available on the back of the P6M, including stereo audio out (unbalanced, unfortunately), a headphone jack, MIDI in/out/thru, and a USB jack for MIDI. You'll also find expression pedal inputs hardwired to control volume and the low-pass filter, and footswitch jacks to control sequencer start/stop and sustain.
The P6Ms voice architecture is built on a foundation of discrete VCOs. Each of the six voices carries two oscillators with continuously variable wave shapes that blend between triangle, sawtooth, square, and pulse, along with a triangle wave sub-oscillator, and a white noise source. The signal passes through two filters: a four-pole low-pass filter inspired by the original Prophet-5 and a two-pole high-pass filter. Both filters feature velocity modulation and keyboard tracking in off, half and full settings, while the low-pass filter can self-oscillate to produce a playable sine wave oscillator. There are two ADSR envelopes, one dedicated to the amplifier and one for both filters. The filter envelope also serves as a modulation source in the Poly Mod section where you can use it to modulate a number of sources including oscillator one frequency, shape, pulse width, and filter cut-off. This is reminiscent of the original Prophet-5 Poly Mod, but adds both positive and negative modulation amounts and two new destinations that weren't available on the original.
Simpler modulation is possible through the single LFO and its five wave shapes, which can modulate the frequency and pulse width of the oscillators, the amplifier level, and filter cut-off. It can be freely clocked or synchronised to the arpeggiator/sequencer/MIDI clock tempo, and the amount of modulation is controlled by a combination of the mod wheel and an Initial Amount knob. While this design sticks close to the Prophet-5, a single LFO feels somewhat underwhelming in this day and age of modern synthesizers. This may be a bit of a downer if you were expecting the beefy mod matrix found on other DSI gear, but there's still considerable sound design potential given that oscillator two can be switched to LFO speed—though this method assumes you don't mind missing that extra tone source. One issue I noticed with the LFO is that modulation of the amp level can introduce some unwanted pops and clicks, especially when using the square wave LFO shape.
A ream of digital brains provide some valuable modern touches to the analogue signal path. The preset system is thorough, with 500 writable user program slots and 500 read-only factory patch slots. You can compare an edited program to the saved version, switch the instrument into live panel mode (where what you see on the knobs is what you hear), or initialise the instrument to a default patch at any time. There's also a capable arpeggiator, an easy-to-use 64-step polyphonic sequencer, and a unison mode for playing stacked chords. Finally, there are two 24-bit 48 kHz effect slots available with a respectable selection of reverbs, delays, choruses, and phasers. Analogue purists will be satisfied to learn that these effects are set up in a sidechain manner so that when they're bypassed, the signal path returns to being fully analogue. However, everyone should be happy about the digital nature of these effects, because they allow DSI to add new capabilities. In fact, they recently included the effects from the OB-6 in a firmware upgrade.
This combination of high-class analogue circuitry with modern technology and reliability make the P6M a compelling instrument. As a Prophet '08 owner, I was enamoured with the playability and the sound of the P6M right from the get-go. Despite the somewhat limited modulation capabilities, a spin through the presets and a day of tweaking revealed no shortage of sonic potential. This is an instrument that could easily serve as the workhorse of any studio and is definitely going on my shopping list.
Ease of use: 4.8
Build Quality: 4.1