Hmmm. More technical-minded Audiogoners out there will be able to explain exactly why, but it can be dangerous both powering up your amp without speakers attached, and even more so connecting the speaker cables to your amp while it's powered up.
Your latest experiment is definitely interesting, but I'm not sure how much it narrows down the possibilities. IMHO, it demonstrates that:
(A) there is--as I think you suspect--some system synergy that is causing the crappy sound. Something like the build-up of a static charge or some such, which gets dissipated when you break connections and turn components off.
...or...
(B) there is--as I suggested before--some kind of partial or intermittent short, poor connection or something similar, in one of the cables or one of the components. As you suggested in a previous post, the mere act of connecting or disconnecting an IC to a RCA jack can change things, physically moving wires or solder joints and hence temporarily "curing" the problem. I once had an expensive pair of Acrotek 6 nines copper interconnect which if dressed in a certain way wouldn't pass any signal at all, and if dressed three inches in another direction worked just fine.
By the way, did you use your own original cables for this last experiment or the new ones?
Your latest experiment is definitely interesting, but I'm not sure how much it narrows down the possibilities. IMHO, it demonstrates that:
(A) there is--as I think you suspect--some system synergy that is causing the crappy sound. Something like the build-up of a static charge or some such, which gets dissipated when you break connections and turn components off.
...or...
(B) there is--as I suggested before--some kind of partial or intermittent short, poor connection or something similar, in one of the cables or one of the components. As you suggested in a previous post, the mere act of connecting or disconnecting an IC to a RCA jack can change things, physically moving wires or solder joints and hence temporarily "curing" the problem. I once had an expensive pair of Acrotek 6 nines copper interconnect which if dressed in a certain way wouldn't pass any signal at all, and if dressed three inches in another direction worked just fine.
By the way, did you use your own original cables for this last experiment or the new ones?