Roland JP-8080 Clipping?

Title link takes you to an interesting post by Don Solaris on Harmony Central regarding the Roland JP-8080 and clipping of its 12db filter. MuzikB was able to reproduce the behavior on a JP-8080, and I was able to somewhat reproduce it on a JP-8000. However, when I did, I was able to tame it by lowering the AMP Level on the JP8000, and I did not hear a difference in regards to clipping between the 12db and 24db filters. Also it only happened on one particular patch for me. Overall I do not get any clipping. My first thought was this kind of makes sense, but then I realized how much I had to turn the amp level down for the particular patch. If you have either a JP-8000 or JP-8080, try it yourself. Check out the thread for more detail.



Some of MuzicB's thoughts (read the thread for more):

"I mentioned the AMP level adjustment to Don earlier but also note that the signal is pretty tame with the occasional amplitude increase into clipping across certain frequencies. You can adjust the AMP level but the jumps still occur. The more I think about it, the more I believe that this isn't a bug or a mistake on Roland's part but that it was made to react this way.

I'll mess around some more tomorrow as it's getting late.

Keep up that great blog matrix!"

I especially like that last thought. : ) Thanks MuzicB!

Update via Don Solaris:
"I would like clear out some things. AMP setting has not much with this issue. The AMP level was at standard 64/127 value. The only thing we can do with AMP is introduce more distortion due its own nonlinearity, but that has nothing to do with the filter overload issue i am talking about. If we take a value of 64 as a standard 0dB gain, when we set it to 127 we are pushing Amplifier into its own nonlinear area which introduces new distortions (due to additional positive gain).

It is a normal thing when you reduced AMP that distortion got lower. But this is true just for values above 64 (say, reducing from 127 to 70). Below 64, you can't reduce the distortion. If you don’t believe me, do the following: Reduce AMP level below 50 and increase the main volume. You will hear distortion is still present. Or try another one. Put AMP level to max and Main level to low, play a note, you will hear distortion. Now put AMP level to low and Main level to high value - distortion is still here. (Please use headphones).

I think this should be also stated in Matrixsynth blog (which i enjoy reading) as people might think they can solve this issue by reducing AMP level. Unfortunatley that is just not possible as AMP is located post filter. And we should not confuse AMP's own distortion (due to its own nonlinearity), with this filter overload issue.

Keep up the good work Matrix, and thanks for putting this on synthblog."

No problem. Thanks Don.