Hi Kiwi,
Yes, I am pretty sure but as I said, I was flabbergasted to hear any difference. In theory, there shouldn't be but there it was.
Playing Sonny Rollins with the FIR filter brought on more body and weight to his tenor sax. With solo classical piano, notes were more fleshed out with the FIR filter. With the SLDY filters, piano highs sound leaner and a smidgen more glassy or tinkly.
If you have the K-01, you owe it to yourself to check out the difference but only after at least 600 hours of break-in. I must emphasise that the differences noted for SACDs are to a lesser degree than for CDs.
Fact is truly stranger than fiction.