The Korg Ex/Poly-800 is a hybird of digital and analogue technology.
It features two digital controlled oscillators, envelopes and one LFO [or motion generator, as it is called here] that are fed into analoge filtering. As additional effect there is an onboard chorus [or delay in the MK2 version] that adds characteristical colours to the device.
The EX-800/Poly-800 has possibly been one of the most modded Synthesizers in the last decades…
The EX-800/Poly-800 has been one of the most modded and bent Synthesizers in the last decades.
There are mods that replace the whole digital core of the engine with updated electronics that gives far more sound sculpturing possibilities than it was made for [see Hawk/Automahawk]
Other more easy to do Mods are the „Atom-Smasher“ Filter mod, the „Moog Slayer“ resonance mod as well as the „FM“ mod. These give the user the possibility to control filter and resonance and some kind of Filter-Crossmodulation by knob. Also a Miniswitch to choose between 12db/24db Low-Pass-Filtering is a simple to Install upgrade.
As i did research on the EX-800, i discovered that the Chorus Rate is another good target for tweaking. Higher Rates can produce very interesting and thick effects.
Also individual Volume-contols for the two oscillators and Noise are very easy to install und provide instant access to these Parameters.
As these signals are present as audio sources before they reach the filter and the VCA section, i also experimented with a Ring-Modulator/Fuzz-Circuit to manipulate the sound. The idea is simple but effective: bend the audio path, modulat the signals and feed them back into the VCF and VCA. I choosed to build a DIY kit of a MS-20 style ringmod: oscillator 1 of the EX-800 is used as its source signal and an onboard oscillator provides a controllable modulation Source. It’s also possible to blend between ringmodulated signaland fuzz. These Signals are fed back into the filter of the EX-800 via the Noise path – which includes an inverting OP-Amp Buffer that makes it to induce signals here. Opening up the signal path and modulating the signals there is a very interesting start of expaning the sounds of the Ex-800/Poly-800. There are plenty more ideas how this could be done. and i just did the one which seemed to be the quickest and easyest version…