The M25 is one of two Swiss Army Knife processors that, along with it's counterpart, the Model 26 Control Signal Processor, provides a bank of essential audio synthesis functions within a single module: a Manual Attenuator, a Waveshaper, a White/Pink analog Noise Source, a Dual-VC Linear VCA and a DC coupled Ring Modulator and Fuzz Distortion -- all under a single 10HP faceplate.

The functionality of the M25 is broken down into three sections:

1) Wave Attenuator / Waveshaper / Noise Generator

With it's Mode switch set to the right, the top section of the Model 25 provides an often overlooked audio synthesis function - Manual Attenuation of both audio and control signals. It's range travels from full attenuation (no signal), through unity gain to +6dB, so that signals can be amplified from their input level by a factor of 2.

With the Mode switch thrown to the left, the M25's diode-based Waveshaper is put into the signal path. The level pot at that point effects both the signal amplitude and the amount of folding. Along with the manual pot, the Waveshaper has a dedicated voltage control input.

WIth no input present in the Attenuator/Waveshaper, the output of the returns a manually-adjustable analog White Noise source. When the Mode switch is thrown to left , the White Noise is shaded Pink. There is also a dedicated unity gain noise output. .

2) Linear VCA

The center section of the M25 hosts a standard linear VCA. Unlike the M13, no filtering is applied to the signal path and both AC and DC sources may be gated. There are two control voltage inputs provided - the first will take the output from full attenuation to unity gain. The second VC input is preescaled for the velocity output of a midi to CV converter.

3) Ring Modulator

The bottom section of the M25 is a 1496-based balanced dual sideband four quadrant multiplier - a Ring Modulator. Boasting over 65dB of carrier suppression, it features a unique corss-modulation Feedback switch not found in other Ring Modulators that introduces harmonic content with minimal sidebanding.


Fuzz Distortion

By running the same signal through both the X and Y inputs of the M25 Ring Modulator and engaging the Feedback Switch, the output is fuzzed (in a very big way). Have a listen to sound sample 3 below.

Click HERE or scroll down for the Model 25 calibration/set-up procedure

Audio Examples

1) The following soundbite consists of two sine VCOs, both controlled by the same M24 output, which are run through the M24's Ring Modulator with the FEEDBACK SWITCH being turned on and off at regular intervals. click

1) There's another example of the Ring Modulator's Feedback option, this time with the same signal (two Ramp VCO's) being fed into both the X and Y inputs. The Feedback is engaged throughout. A second voice is added halfway through the soundbite, then a third with a shorter envelope. click

3) Fuzz Distortion - This sample gives an example of using the M25 to produce Fuzz distortion. The identical signal is run through both the X and Y inputs of the Ring ModulatEDDBACK switch is engaged. click

4) 2 examples of the Waveshaper on a single sine wave VCO. The first is a manual sweep of the attenuation pot click, the second is the effect from a fixed setting of the pot when the sine is gated through a VCA prior to being being run through the waveshaper click

5) One patch, four rmodules involved -- none of them filters: Two Model 15's (both sine) into the M15's Ring Modulator set with a closed feedback loop, then through it's VCA with that output routed through the Model 25's Waveshaper, them to the speakers (with a little TC4000 reverb added). One Model 10 controls both the VCA and Waveshaper. Again...no 'filter' in this patch. click

6) An even simplier patch, but no less interesting: Sine into Waveshaper, one hand on the VCO freq knob, the other on the Model 25 attenuator, which is opening and closing the wavefold function click

Model 25 Demo's from REwire:

Model 25 Demo's from REWIRE:

Sine to Waveshaper - LFO to WS CV input click here

Saws to Waveshaper - Theremin Control of WS CV click here

Sine to Waveshaper - Fast LFO to WS CV click here

Waveshaper Noise - Triangle to WS CV click here

Ringmod - Flip Feedback Switch click here

Ringmod Sequence - Env to Freq of Sine click here

Ringmod to Waveshaper click here

Ringmod to Waveshaper - Sync LFO to WS CV click here

Ringmod to Waveshaper - Repeating Env to WS CV click here

Ringmod to Waveshaper - Env and LFO to WS CV and OSC CV
click here

Ringmod to Waveshaper - Theremin Control of WS CV click here

Ringmod to CV input of Waveshaper - Triangle to WS Audio Input click here

Ringmod to Waveshaper - Env to WS CV - Flip Feedback Switch click here

Sine to Waveshaper - WS to Ringmod - LFO to WS CV click here