Dethklok: What prompted you to switch from the XA 30.5 to MC452? We have had the MC452 for a year and like it a lot, with no complaints. That said, I am wondering about switching from the MC42 to Pass X250.5, mostly to take advantage of the 15 initial watts of Class A. Please see my recent thread and would appreciate any input.
Mmurphy: I have not owned the 402 so cannot speak to it on personal experience, but have read a lot about the 402. I have owned the MA6600 and MA8000 before the MC452. To my ears (and in my listening space), the 452 is more transparent and neutral. To the extent the 402 presents slightly warm and rich, consistent with the McIntosh tradition, the MC452 does not. It is uncolored, and simply amplifies, effortlessly, what it is fed. So, for example, when running BAT 6h30s in the Act2.2 pre, the 452 accurately conveys those tubes' great sparkle, detail and highs, and the mids are true to the recording, but to my ears was somewhat lacking in mid-bass and bass -- which is the focus of your question. We recently rolled the Act2.2 to NOS 6h30 DR (circa 1970). The change was dramatic. We gave up some (not all) sparkle and separation, but the mid-range, mid-bass and bass are now in bloom. Slam to spare. The point is that the MC452 gets out of the way and does its job of amplification, and does it very well. Per my recent thread, if we replace the 452 in our main system, it will be no knock on the 452; indeed, we will be keeping it for a second system.
