We listened to the Korato on the Quads, with the Mac C220 preamp which sounds better than Cary on SE output, still with RCA tubes, groverS graphite ICs, balanced Equitech power, with Black Sands Silver Ref 5. It was improved since last time, a little more body, and quieter, darker background. Playing on the quads with 79dB sensitivity the tone still gets a little shrill on dynamic peaks which demand more power. Playing it on my far easier load and more veiled Legacys I thought it sounded OK, the improvement was obvious to me and Sol who have been working on it and noting the gradual improvements in before and after comparisons, but still not what we had hoped. I'm sending it back to Bryan so he can see about further investigation by someone intimately familiar with the DNA. It never reached the smooth satisfying powerful sound that I heard it make at RMAF with ACI Sapphire XL, so I can only think that there is still an errant part in there or something. I really look forward to hearing it again in good health at BSP Audio's next show exhibit. Thanks for the loaner Bryan! Sorry it was such a weird ordeal. But you got our honesty and best effort!
Today Bryan asked me to listen to the Korato on different speakers, especially the Ushers where we listened to it during the last meet. Thinking that the inefficient Quads were giving it grief. He is so confident in the Korato that he is unwilling to rest with a negative audition sitting out there. I don't blame him. I have felt awful during this whole ordeal, because it sounds pretty good on my system, then we play it at a meet and it sounds unexpectedly and frustratingly "less good."
So on his request I tried it with Usher Be-20 again, sounds good! Whats up with this? Why does it sound bad at meets and better after the meet? I remembered that we used the McIntosh C220 preamp for both Korato demos, at both meets. I use the EE Minimax in regular listening at home, preferring it to the Mac. We all agreed before the first meet that the Mac was the best choice considering its "fine heritage," made even better with its new NOS RCA tubes. The pre sounded 100% better with the new tubes than with the old Chinese tubes on my Snappers, and everyone felt the most comfortable with it, over the minimax. I have never preferred the Mac, but didn't think it a big deal since the differences between it and my EE Minimax were so slight - ON MY LEGACYS - which are rather 'musically veiled' anyway. On the Quads and Ushers the Mac preamp has not been played much, the Minimax advantages are more obvious with those hi rez speakers - and so too with the Korato.
Playing Korato with Minimax on Ushers had none of the peaky, harsh and gritty, overly dynamic stabbing peaks that we heard with the C220 at the meets. The Korato with the Minimax were very listenable. It was not perfect though; there is a slight ringing 3rd/4th harmonic overtone, maybe -30dB (I'm estimating based on the sound, but could be wrong) that happens with upper midrange instruments (1kHz) like flute, trumpet, piano using the Minimax. Everything below 1kHz is perfect, beautiful. The ring could be a reactance of the output tube to the Korato input or some other kind of ringing, I don't know if that's even possible? But I do know that the Korato is somewhat sensitive to its preamp. It sounded near perfect with the Korato preamp in front of it at RMAF. I can understand better now how that great TNT Audio review and others are so positive about this little amp when they have a good complimentary preamp in front of it.
The frustrating thing is that we had one of the world's great tube preamps here at the last meet, Hantra's Cary Audio SLP-05, but we didn't use it on the Korato. The equipment stand was jammed full of heavy hot amps with tangled wires, so we just said fuck it, the Mac worked on it last time (flawed reasoning) so we'll use the same preamp again to see if indeed the amp is better now (more flawed reasoning.) The correct audition would have been to insert the Korato into the system that we had been listening to so we could minimize variables and judge it by itself. Switching to the Mac preamp out of convenience added an extra variable and was a mistake. At least at the previous meet, the Mac served as the main act for the whole meet, and of course it sounded fine with it's brand mate the MC402, so we didn't suspect it as being a problem. We shold have fought for the little Korato harder and tried whatever we had on hand to help it play its best. I was sensitive to complaints that previous meets had too much swapping and not enough music playing, so I was trying to avoid too many pauses for rewiring.
When bigfish8 auditioned it at his house, he used Candella with some nice cushy tubes which the Timpieces enjoy. The Korato sounded good there, and we attributed it to the bias adjustment, but it was really the nice preamp that made the difference. The Korato kept up with the Oddysey Monos pretty well. A slight bit more grain than the Odysseys, but still well within the high end bracket and a pleasure to listen to, at a lower price.
Sorry for the confusion everybody, especially Bryan, Korato fans and customers. We all thought that the Mac pre was the way to go for the Korato audition, so it was just one of those things. I encourage anyone who is interested in the Korato to audition it. Hopefully it will be at RMAF again this year, as part of a well matched system. Hearing it in MS at BSP Audio would be ideal, with the Korato preamp, or any really good quality pre. It is a good amp that deserves a great front end.
Rich