I love my MC240 amp. It does sound better, especially playing piano music. It is paired with APT Holman preamp, and AR90 speakers. Paid $50 for the AR90s, had to replace the surrounds.
I also have 3 sets of Adcom amps/preamps, with various speakers, (KLH, Pioneer) and they sound just fine to me.
I pretty much leave them all on all the time, even when there is no music playing, and have not replaced any tubes in the Mac in the year or 2 that I have had it. Before I bought the Mac, the seller had it checked out by a specialist shop.
I am content, but seem to have an endless curiosity about speakers. I bought some Klipsch KG4 speakers, wanted to try out those horns, liked them at first, but got weary of them pretty quickly, will sell them when I get around to it. Found out that I prefer the old KLH and even the old Pioneers, both pairs cost less than $100.
I use cheap thick speaker wire.
My source is a big external hard drive on my desk top computer.
I download torrents from P2P sites, all HD (eg flac), never bother with MP3, so it's all free.
I concede that vinyl might sound better, but I cannot be bothered trying to keep vinyl clean. I have a dog, and I live in the country, and there is lots of dust in my environment. Clean hard drive sounds better than dirty vinyl.
Also I love the convenience of finding/selecting on the computer.
Makes it easy to "stack" some music when I go the bed. Or choose a song that I am trying to learn, and be able to have it repeat without putting my guitar down. Or copy onto a cd to play in the car.
