Joining this discussion a little late. I recently upgraded from a shelter 501 to a rebuild Koetsu black. My listening interests are mostly blues, jazz and a lot of Indian music (I have lots of LPs from the 60s/70s). The rest of the system is decent
1. Well tempered classic with JMW 12 tonearm
2. Zu Omen Mk2's and zu event cables
3. Ifi iphono black 3
4. Benchmark LH 4 preamp ( I swap sometimes with a fantastic preamp built by my friend for me
(Sridhar)
4. I also have 811 based monoblocks driving the Zu's built by my friend
If I thought that the shelter 501 was good with vocals, the koetsu black is several notches better especially in the midrange. I cannot believe how the same vinyl sounds so much better (more details seem to be easily heard). Granted my shelter was old but this is really good. I have a month to evaluate the Koetsu black and in case I do not like it, I can exchange for a kiseki or others. But so far the Koetsu has been outstanding. Have not yet listed to rock etc with it.
Also, I have heard the same records played back with Lyra Delos; the Koetsu definitely seems better to my ears. The dealer who I bought the Koetsu from was suggesting that I should upgrade my player to a Merril with a kuzma 4 pt tonearm --) way over what I can afford right now.