Interesting- I had no issues with this mod on my similar OC-2, no noise, and some obvious headroom improvement (though the headroom improvement isn't huge, it is apparent). Are you sure you got both of the correct components? The OC-2 will always be somewhat dirty, as part of the circuit involves clipping the waveform to create something resembling a square-wave before it is filtered back down to something smoother- that grit is really part of its charm. Then there can be less-desirable clipping of the op amps if you feed it too much input, which sounds harsher and more "separate" from the main signal. I almost always play my OC-2 with a compressor in front both to improve tracking (via both the compression and a tone control on my compressor) and to tame the input signal down a bit to limit clipping and rarely have headroom issues anymore, though I bought many of the suggested components from this thread some time ago to mod one of my OC-2s just to see what would happen (haven't gotten around to the mods yet)
