I just purchased the HD preamp and have had similar experiences to John. I came from an Aesthetix Callisto signature with a bunch of NOS tubes. I really liked my Aesthetix and had it for many years. I listened to the Classic pre with MPS power supply (a must for this preamp IMHO) and really loved it. I was able to compare and preferred the Classic/MPS to the Koda and the ARC ref10. The Classic was more resolving with greater texture and color. It had a certain ease and beauty that none of the other preamps possessed.

I made the the mistake of borrowing the HD..... it’s a game changer. Everything the Classic did the HD not only did better, but took the show to some other planet.