Forums > MaxMSP

max , dc-coupled outputs, cv

June 20, 2009 | 7:05 pm

hello forum!
i must start sayng im a total n00b in the maxmsppuredata world.
im on max 5 on a mb with a motu ultralite first version.

i also have a korg ms-20.

i succesfully built a multi-waveform lfo to send to the ms-20 via audio outputs of my soundcard.
it works a charm (but i hav no multimeter to check properly the output voltage, just pluggged, it worked, felt satisfied Very Happy )

being also unskillful in math and electricity can someone help me understand how to build a proper hzv interface in max to drive the ms-20 oscillators?

thanks in advance!
giona


June 21, 2009 | 9:12 am

first you need to work out what signal value in max produces a voltage of 1v. Start at 0. and gradually raise the signal till the multimeter says 1v

then you can use this to convert midi notes 0-128 to the right values for you ms-20, replacing the value 0.2198 with the reading you took for 1v

#P window setfont "Sans Serif" 9.;
#P window linecount 1;
#P newex 187 214 105 196617 scale 0. 1. 0. 0.2198;
#P newex 187 189 217 196617 expr (0.25 * exp(.057762265 * ($f1 – 36)));
#P connect 0 0 1 0;
#P window clipboard copycount 2;

oli


June 21, 2009 | 11:56 am

thanks oli gonna try it right now!


June 21, 2009 | 12:05 pm

by the way, you mean using a cycle~ at various frequency and amplitude values till i reach the 1v ?
and also, when you have the time, can you explain the methods of conversion you applied? so i learn some math too Very Happy

thanks again


June 21, 2009 | 6:21 pm

no, you either want to connect a numberbox to a sig~ object or use the numberbox~ object


June 21, 2009 | 6:30 pm

thanks. but i cannot see a numberbox~ object, only a number~ object. is that the one you mean?


June 21, 2009 | 8:01 pm

that’s the one.


June 21, 2009 | 8:40 pm

oli, i love you.
after messin around triyn to understand the multimeter everything worked out and now the cv to vco is PERFECT!!!!
thank you!

(who needs volta ??? Razz )


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