Tuesday 20 February 2024

Mun - Build notes - NLC Vocoder - part 1

These are my build notes for the nonlinear circuits Mun module.
tHIS eurorack 22HP module is a 10 channel vocoder based on the Syntovox 222


The word Vocoder is a combination of two words.
Voice + Code = Vocoder
Vocoded signals were essentially a form of data compression for voice.

Links
Wiki
+ BOM

The module is more easily understood if you divide it into 3 sections : Voice, Carrier & noise

For the Voice section, there is a TRS/mono 6.35mm input for mics, a stereo/mono 3.5mm input for line level sources (like a tape/CD player or phone with a jack output) and 
a synth level input (+/- 5V).

The Carrier section has a synth level input only.

The Carrier input expects a +/-5V synth level signal. One tip - the
vocoder output is only as good as the carrier signal, so mix a few
signals together via phasers, filters or wave-folders to get interesting
sounds……or drum hits are fun too.






Noise:
This is a transistor based noise source with pots for level and colour (white/pink). 
The noise signal is mixed with the carrier signal on channels 9 and 10. 
The level pot determines how dominant it is. 
This is simpler than voiced/unvoiced switching seen on some vocoders but I found
it sounds good and like having the option of patching the envelope inputs so the noise turns
on a lot more frequently than it should. Of course, you can turn the level pot down to 0 
and have no noise too. 




It basically works this way:
You plug in your mic a one end where you voice is converted into control voltages.
(in this case CV envelopes, that exit from the envelope out jacks).

Those CVs are plugged into the envelope in jacks (of the carrier section). 
They are used to control the synth plugged into the carrier input.








The filter and envelope outputs can be used without affecting the main
vocoder operations. Patching into Envelope In, disconnects the
internally generated envelope. A 0-5V signal is expected.



Shall we have a little talk? .... Robert Sheckley
It's the title of a Neubla Award nominated novelette which originally appeared in Galaxy Magazine, October 1965.

The story can also be found in the collections The People Trap (1968), The Wonderful World of Robert Sheckley (1979), The Collected Short Fiction of Robert Sheckley: Book Three (1991), The Masque of Mañana (2005) and Store of the Worlds: The Stories of Robert Sheckley (2012).



The name of this module "Mun" comes from this novelette.
It's a unique novel as it explores communication & specifically linguistics in science fiction.

Basically, the Alien society's language mutates so fast that a Earth linguist attempting exploitative First Contact is barely able to keep up and retires defeated when the latest iteration reduces the entire language to inflections and stresses of a single syllable: "Mun, mun, mun-mun." ......................Quite an appropriate name  for a vocoder.

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"Mun," said Erum, shaking his hand enthusiastically.

"Same to you, kid," Jackson said.  He had no idea what the word meant.  Nor did he care.  He had plenty of other Naian words to choose among, and he had the determination to force matters to a conclusion

"Mun!" said the mayor.

"Thanks, pop," said Jackson.

"Mun!" declared the other officials.

"Glad you all feel that way," said Jackson.  He turned to Erum.  "Well, let's get it over with, okay?"

"Mun-mun-mun," Erum replied.  "Mun, mun-mun."

Jackson stared at him for several seconds.  "Erum, baby, just exactly what are you trying to say to me?"

"Mun, mun, mun," Erum stated firmly.  "Mun, mun mun mun.  Mun mun."  He paused, and in a somewhat nervous voice asked the mayor: "Mun, mun?"  (pp. 64-65)

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Parts
There are lots of caps and resistors ... Its a big build.
Though parts are all pretty common ... nothing rare.
TL072 or TL082 x 16 Soic Tayda: A-1139... cheaper from mouser
TL074 or TL084 x15 tayda A-1137 or A-1140 ..... cheaper from Tayda
BC857 10 tayda A-1345
BC847 3 Tayda A-1339
LL4148 24 sod-80 Tayda: A-1213






5V1 zener 20 Tayda A-6014 (5V6 but ok).... order these




LM13700M or V13700M x5 Mouser Part No 926-LM13700MX/NOPB 
or
V13700M at synthcube (cheaper)

i USED 
Mouser Part No 926-LM13700MX/NOPB 


I've run out of op-amps.
To be continued when they arrive................... mun, Mun, munmun MUN

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