I've been running these amps about 4 hours a day on the weekdays and 8 hours a day over the past 2 weekends for about 50 hours total. I sat down this morning to have my joe and turned it on. I haven't really sat down and listened over the past week, just had them on for some music.
The Mac guys over at AudioKarma said to give them about 35 -40 hours. I really wasn't sold on this burn in idea since my gear was used until I purchased the mono's new. I had thought my 352 was a little warmer, which I like and the 501's a tad bright. This morning was like a light switch was thrown. The 501's sound much warmer than a week ago and the bass which was somewhat thin has locked on and I am quite suprised by the bass reproduction without the sub turned on. The mids are very smooth and crisp, just to my liking. I never quite heard the definition as I'm hearing now as in guitar notes and chords. The congestion has cleared up and the seperation is just stunning.
This is my first attempt at a review. I'm very happy with this purchase. For those that like McIntosh, the 501's are something else compared to my 352. I usually have buyers remorse no matter what I buy. Not this time. I would buy them again in an instant. Although a pair of 275's may be nice also!!
Gordon