Make Noise Maths Revisited

The Make Noise Maths has been around for a long time.
This is one of the first modules I ever bought. It's often described as an analog computer.

It's basically two function generators & two attenuverters in one module. 

The circuits are loosely based on the Buchla 257, 281 and the Serge DUSG.

It has many uses. It can be used as a VCO, a mixer, an envelope follower, a slew limiter, 

an inverter, and do some basic logic functions.

One of my friends is going to buy one and wanted to know the difference between the two.
I have the "classic" (original) version on the right. It's pre 2013.
(Sometimes referred to as the Lighting Bolt version)

I've read that the two versions sounds different when used to process sounds as a filter or mixer.
If anyone out there has both I'd love to hear your opinion.

There are some obvious external differences between the two such as the different knob layout
and the addition of LEDs to indicate +ve & -ve voltages and to show the state of the (EOR) End Of Rise and (EOC) End Of Cycle.
You will  also see there are 13 outputs on the update & just 10 on the classic.

One important difference is the Function output (or Unity Output on channels 1 & 4) of the new module. 

The Signal OUT Multiple (from the original MATHS) has been changed to a Unity Signal OUTput which is the non attenuated output of the

function generator (different from Ch 1 & 4 outs)


This non-attenuated out is a good output to use when you do not require attenuation or inversion or when you want to use the signal both independently and within the SUM/OR Bus.

And an INVerted SUM OUTput has been added for greater modulation possibilities.

Finally, the new MATHS has added +/-10V offset range (CH. 2). User has choice of +/-10V offset at CH. 2 or +/-5V offset at CH. 3. (The original only has a +/- 5V offset on both channels 2 & 3),

According to the Make Noise manual
MATHS revision 2013 is a direct decendent of the original MATHS,  sharing the same core circuit and generating all the fantastic control signals that the original was capable of generating, but with some upgrades,
additions and evolutions:

The new Maths has a Cycle input (24)
This allows for voltage control of the CYCLE state in Channels 1 and 4.
On Gate HIGH, the MATHS will CYCLE.
On Gate LOW MATHS will not CYCLE (unless the CYCLE button is engaged).

It's useful to think of this module as a processor of equations.
There are 4 inputs: CH1, CH2, CH3, CH4.
The two outer channels are function generators. The 2 inner are basically simple inputs that are normalled to a DC offset using attenuverters.

 Each channel has a coefficient which multiplies the value by +/- voltages (using the associated attenuverters).

 

The outputs can be OR/SUM/Inverted.

The inverted is only present on the new version.

OR = MAX ie it takes the largest value.
Eg. if the outputs from channels 1-4 are 1V, 3V, 5V, & 5.2V , then OR will output 5.2V.
It does not respond to negative voltages, therefore it could also be used to rectify a signal.

SUM adds the outputs from all the channels.
Depending upon how the Attenuverters are set, you could add, invert or subtract voltages from each other using this circuit. This is a good output to use for combining several control signals in order to generate more complex modulations.

INV = inverted SUM. It allows you to modulate backwards!

When utilizing the SUM, INV and OR OUTputs, set any unused channels to NOON to avoid unwanted offsets.
The output jacks 1, 2, 3 & 4 are normalled to the output jacks OR, SUM & invert.
That is, if you plug a cable into any of those 1,2,3,4 jacks, that voltage is subtracted from the OR, SUM & invert output jacks.

Using the Function Generator:

Its different to a standard LFO in that the rise and fall knobs sculpt the envelope and set the frequency.
They determine the rise & fall times... that is the time it takes for the envelope to rise to the peak (10V) and then fall to 0V. Also you can use the Log/linear/exponential knob to determine the shape of the rise & fall. Longer cycles will be achieved with more Logarithmic response curves. The fastest, sharpest
functions will be achieved with extreme exponential response curves.

This style of envelope generation is classic "west coast" and follows in the footsteps of the Serge DUSG and the Buchla 281. It's so very different to the ADSR type envelope generators of the "East".