Audio input is the easiest way to acheive this, you will need a rectified voltage doubler
with the positive output connected to the middle terminal of the CUTOFF pot you have
installed for the MOOG SLAYER mod. You certainly could use another pot to control
the amount of the external audio modulation and it can be done either by using a
switch to select the audio input destination (VCF AUDIO IN or VCF MODULATION)
or you can add a second audio input exclusively for modulation. Now don't try
to split the same signal or the modulation will suffer with severe voltage drop,
use a stereo input instead. Schematics for a rectified voltage doubler can be found
here: http://www.muffwiggler.com/forum/viewtopic.php?t=14328&highlight=voltage+doubler
It's easier to use a external noise source fo either VCF AUDIO IN and VCF MODULATION.
About FM keyboard track I believe it is already tracking the first voice of DCO1 using pin 7
of IC4 , first voice of DCO2 should be at pin 7 of IC5, the problem is the Poly 800 has
only 1 VCF for all the voices so if you play more than 1 note at the same time it
will keep FM at the first note rate.
My Poly 800 II have a rectified voltage doubler for CV input already installed but
I use it for inputing LFOs from Silent Way, it's basically a VCF CV IN with a voltage
doubler, I never tried to use it as an envelope follower of the audio input source
but I'll give it a try today when I get to the studio, in theory it should work like a
champ.
PS: Take care with the level of voltage you send in the VCF, a regular CV source
should never be connected to the voltage doubler as the maximum voltage the
VCF can take is +8V, the voltage doubler circuit should give you a 0 to +5V slope
using a regular audio interface.
Em 22/07/2011 06:23,
7yash < josh.nursing@... > escreveu:
Here is my first test with the FM-800 mod. Needless to say that after the Moog Slayer and 12dB mod, this is supremely interesting as a simple way to extend the timbral capabilities of this 80's synth:
http://www.youtube.com/watch?v=ZcUj3xzt3YE
The sounds you can get with the FM mod, in cooperation with the Moog Slayer mods are fantastic as they are: lots of resonant blips and growls and many other effects. It's best used as either a source of new timbre when arpeggiating in mono mode (or full-octave poly) or as special effects. Or you can also use it as a type of distortion. Some fifths sound great too.
Now, the questions are:
1. Can this FM pot mod be made to track the keyboard so that chord plays are not that dissonant?
2. What would be necessary to rewire this mod so that I could use it with either DCO2 or the internal noise/External Audio Mod as modulation inputs? Is a simple multi-way switch enough or there needs to be other parts?
I am also interested in the particulars of this mod, i.e. the details by which this DCO1 FM effect is realized. It will help me understand more of the schematics and the architecture.