Hi Don,
I found a blog post in which a guy added a noise knob to his EX800. He doesn't say how well it works or anything. But he apparently just replaced VR3 with a full-sized pot. Not sure what value he used, though.
Click here to see pictures of the mod. Aaron
--- In korgpolyex@yahoogroups.com, "backshall1" <backshall1@...> wrote:
>
> The filter FM needs a lot of harmonics to work with, so playing an interval
> like a fifth really works well. You can do that with the chord memory, or in
> double mode you can set the DC0 2 interval (parm 31). I don't think the
> internal sequencer works when you are using chord memory so if you need the
> sequencer you will have to use a double mode patch to get the interval. Set
> the cutoff way down low, the resonance way up, and add a touch of FM.
>
>
>
> I have also been thinking of adding a noise level knob, mostly because if
> interactions with the external input I added. There seem to be three choices
> when it comes to where to inject the external input signal into the VCA/VCF
> (DCO1, DCO2, Noise). I currently have it connected to the DCO1 input but was
> thinking of moving it to the noise input. In that case, I believe parm 33
> would need to be up high to let the external sound through but then I would
> get noise too, so a separate knob for noise level would be essential. I
> would be very interested in hearing from people who added an external input
> to see how they did it. There are definitely tradeoffs among the choices.
>
>
>
> As for adding the noise knob, it might be as simple as replacing VR3 with a
> full size potentiometer. It would take some testing to determine the exact
> value to use, and R34, R35 might need to be changed so you can get the
> minimum noise level down closer to zero. The current value of VR3 (1 Meg)
> will take the noise level well above the factory spec of 0.3V p-p, so you
> have to be careful there. It might be easier to put the pot from IC2 pin2 to
> ground. Like I said, this needs some testing unless someone else has already
> done it.
>
>
>
> Don Backshall
>
>
>
> _____
>
> From: korgpolyex@yahoogroups.com [mailto:korgpolyex@yahoogroups.com] On
> Behalf Of AARON
> Sent: Friday, November 23, 2012 1:48 AM
> To: korgpolyex@yahoogroups.com
> Subject: [korgpolyex] Mods complete (for now, anyway)
>
>
>
>
>
> After thinking about it for a long time, I finally did it. Or "them," to be
> more accurate. Within the last couple of weeks, I've done mods to two of my
> Poly-800s: the Moog Slayer, 12/24 dB, FM-800, and battery backup on one
> machine, and just the Moog Slayer on the other.
>
> Obviously, these mods really open up the sound-making capabilities of these
> machines. At first, I didn't understand what the FM-800 was capable of until
> I did some reading. Then, once I figured it out, I was blown away with what
> it can do, and really glad I did it.
>
> The only other thing I'm thinking about doing is putting a knob on the front
> panel to control the noise level (parameter 33). Has anyone done it?
>
> Aaron
>