I polished up the can caps and they can be slipped into the slots for show. But I decided to leave them out to keep the hole open for additional ventilation from under the chassis without having to break out the drill (not an option). Also, since the caps are in the "back", at least the way I have them on the shelf with the power switch and connections facing forward, and running the cages in place (but not screwed down so special guests can see them naked) you would not see the cans anyway. They are very quiet, slight hum from the amps, I don't hear any hum through the speakers until about 3/4 volume with no input, using a McIntosh C33 preamp. Regarding sound, I like them very much, I don't have experience comparing dozens of amps to each other, but did compare these head-to-head with my everyday MC-2155 (150wpc solid state) McIntosh power amp. The Dyna's had a presence and "real" sound that the Mac clearly does not (at least in comparison). Tried through Klipsch Heresey II's and 14" 2-way JBLs, with similar results. Not sure if this is a fair fight (tube vs. ss), but I would give the first round to the Dyna's And yes, the Mac is up to snuff, with relatively recent full recap and then additional check out and work done by Audio Classics. That said, I have only put a few hours on the Dyna's so still listening and learning what goodies these ~60 year olds have to give. At this point I am very happy with the "stock" sound, and not inclined to modify them further for the foreseeable future.
