So why are you upgrading it? Looking for more power? If the Yamaha or Mac are of the same size, I doubt you will be moving up. Just a lateral move. If you think the Yamaha is going to sound sweeter or better, you may be disappointed. Those early B&K models had a great smooth sound to them. But an upgrade in power will give you more to work with, drive bigger speakers and fill larger rooms, but still may not actually sound better. Glad to hear you will be keeping it, so you can see how much improvement you get, or don't get.
Way back in 1986 a B&K ST140 system was driving a pair of Vandersteen 2C's with a Sota 'table, at the local salon. I was completely blown away and moved by its performance, especially at its price point. I think I could have bought it all for $1200. But I had just sunk my money into an Adcom 555 and system before I got there. Oh I was still happy with what I had, but I was very impressed to say the least. Brings back memories.
Way back in 1986 a B&K ST140 system was driving a pair of Vandersteen 2C's with a Sota 'table, at the local salon. I was completely blown away and moved by its performance, especially at its price point. I think I could have bought it all for $1200. But I had just sunk my money into an Adcom 555 and system before I got there. Oh I was still happy with what I had, but I was very impressed to say the least. Brings back memories.