Korg Poly800/EX800 Users

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.

Thanks for the detailed reply, Bill. I love this group and the helpful people like Mike and you :)

I am not sure I get everything you say since I've only just begun doing DIY mods, but maybe I should break it down into smaller, manageable parts first. So, Silent Way is on my To Do list, but it appears a jump in complexity for me with the potential of damage for now.

In the meantime, to simplify things, this is what I'd like to (and the circuitbenders.co.uk guy has done more than that): a simple switch to select between the External Audio In and the DCO1 for the FM mod input.

I've asked over there how he does his External Audio In and he chose to use the NJM2609's P 20 - Mixer Signal 2 In & P 21 Mixer Signal 1 In instead of the Noise pin hack (both work).

So assume I'm doing the External Audio In mod then I want to switch between DCO1 and this External Audio In mod for FM.

It looks to me that a two-way swi tch should be in order, but I am always asking because I wouldn't want to miss a protective parts and damage anything.

Let me clarify: I would like to be able to use the External Audio as FM input instead of DCO1 (as in the FM-800) at will.

Ah, I think I get you now, Bill: I was thinking External Audio as "WAV" for instance into the FM Cutoff CV IN, which doesn't work, right?

Instead, I should think in terms of External CV In into the FM Cutoff CV In, is that it?

Thanks for being patient with all these explanations, Bill, I am slowly starting to get it.

The thing is: with a single jack, will I be able to route the audio and the CV internally in two different paths?

Bill, a question about using Silent Way with the Poly-800.

Let's imagine I can use 4 different Silent Way CV signals to send to the Poly-800, and the latter does have 4 CV inputs into the VCF chip.

Do I need to be careful about the combined Control Voltage amounts and try to keep it below 7V or 8V in total?

Bill, a question about using Silent Way with the Poly-800.

Let's imagine I can use 4 different Silent Way CV signals to send to the Poly-800, and the latter does have 4 CV inputs into the VCF chip.

Do I need to be careful about the combined Control Voltage amounts and try to keep it below 7V or 8V in total?

These are the 4 CV inputs I was thinking about actually.