1-R170 has much effect. I wasn’t looking for the right thing.
2- C287 has still no visible effect.
3- -25db bleed is still present
4- The picture above is because I messed with R170 without understanding they meant horizontal “Symmetry”. Much better now.
5- More often than not, for a brief moment, the trace gets taller as if more voltage was input...
That happens pretty often, (too often if you ask me), and the signal doesn’t seem to be extremely stable. Flickering vertically just a tiny bit too. It’s hard to explain, but my overall impression is that it’s not very healthy.
On a side note, all pots were cleaned several times over, both with IPA and a good, non lubricating, contact cleaner that doesn’t leave any residual stuff anywhere.
(OFF TOPIC) PS: I bought this contact cleaner once at an all-purpose hardware store to test It, because it was dirt cheap.
I never went back to the much more expensive stuff. It’s from the U.K., so some of you may have seen it or even used it. Here it’s part of the “3-EN-UN” TECHNIQUE (“3-IN-ONE“ TECHNIC), line of products.