After listening to the HPA-9 as a preamp in my system for over a week, IMO it has the Rogue RP-1 beat hands down, as well as the new (i.e. post 2015) version of the Quicksilver Line Stage Preamp. It's possible I'm just not a tube guy, but both of these preamps are supposedly highly detailed, low distortion, and not "tubey" in the traditional sense. The Nuprime extracted more detail, offered a bigger soundstage, a blacker background, better instrument separation, and bigger dynamics/faster transients. It's important to note, though, that although I listed to all three of these preamps in my home stereo system under substantially identical conditions, these auditions were not performed at the same time, and I didn't have a chance to level match them.
Where the Nuprime might have met it's better as a preamp is the Hegel P20 (retailing for $2900). The Hegel threw a deeper soundstage and seems to extract more spatial information. I really would like to have a holographic sound, and although I generally like what I hear from the Nuprime, in my system with my speakers and my other electronics, I get a wide soundstage, but it's not deep. It is rather two dimensional. The Hegel presented the depth that I'm missing. But while the Nuprime lost to the Hegel it that one area, I believe it has an edge in portraying clarity, vividness and separation of instruments, especially horns and percussion, probably due to faster transients. The Hegel put me farther back in the orchestra, so to speak, for better or for worse.
At 2900, the Hegel is beyond my budget for a preamp, but there are several currently available on the used market between 1500 and 1900, which I could swing if it were hands down better than the Nuprime. While I'd really like to have its three dimensionally, I'm not prepared to give up the sheer presence that the Nuprime offers. So, I find myself asking whether the Adcom GFP-750, which I had in my stereo rig for years on loan from a friend, had this combination of attributes? I think it might have. Unfortunately my memory isn't good enough, and any differences between these pres are really just matter of degree. I know it presented a vivid sound, but can't be sure it was as vivid as the Nuprime's. If one were available at a dealer, I'd demo it just as I have these other pres, but the 750 was discontinued more than a decade ago. Also, while it's not a show stopper, any that I find on Audiogon or elsewhere are most likely in need of a recap, which besides costing a few hundred dollars, is way more of a headache than buying gear that is new or like new.
If I knew for certain that for ~1500 for a 750 recapped and shipped to me, I'd have preamp that posesses the best sonic attributes of the Hegel and the Nuprime, I'd do it. Lacking that knowledge, I'm thinking that I'll stick with the Nuprime. It's 95% of what I want for just $650, pretty amazing! Down the road, if I find a preamp that gets me closer to sonic nirvana, so be it.
If anyone else has thoughts on the HPA-9 as a preamp and can compare it to others, notwithstanding a price difference, I'm very interested in your thoughts.
