although i don't care about this little bleeding or little hiss from the bucketbrigade at all
(and if so i would noise gate it when recording)
i copied this here from the - very informative -
soundonsound review:
"...Of course, nothing is perfect and, early on, I discovered that the MatrixBrute suffers from audible bleed from the oscillators through VCF1, even when all of the Mixer levels are at zero and all of the routes to the filters are defeated. I raised this with the engineers at Arturia who told me, “We had made the decision to pack the MatrixBrute with lots of features, which meant a lot of circuitry. So, when it came to the board layout it was difficult to avoid crossing the filter area with pitched signals such as the VCOs. To give you an idea of the complexity of the problem, this board has around 6000 components so, while it wasn’t something we wanted, choosing to implement a 24dB/oct Steiner Parker filter — which is sensitive to bleeding from nearby PCB tracks — led to this issue. But if you push the VCOs to very high frequencies you can eliminate it.” I tried this, and it worked. So did turning the output from VCF1 to zero when it wasn’t needed!..."
my recommendation is: play the matrixbrute over a fat bass amp and not with a headphone.