Hasse, just about every tube preamp I have listened to has a slight bit of hissing noise in the background but usually only noticeable if you place your ear up to a speaker. I noticed this with CJ PV-12, CJ PV-14, and AR LS16 but once I back away from the speakers its gone. I believe this is normal background hiss generated by the tubes. If its a real loud hissing sound, there might be something wrong. Otherwise I think its normal. My solid-state preamps had no hiss or noticeable background noise but done of them has that magic tube sound either.
In addition to the tube preamps listed above, I have owned Classe CP-45, Classe CP-35, and Adcom GFP-750 solid state preamps. As you can see, none of these are real "high-end" preamps although the AR LS16 is the most expensive (LIST).
Here's a brief summary of my findigs as they apply to my system.
CJ PV-14: Nice warm smooth midrange with good sound stage but slightly rolled off frequency extremes, top and bottom. I won't mention the CJ PV-12 because its been so long since I've owned one I barely remember what it sounds like.
AR LS16: Not as sweet in the mids and compared to the CJ PV-14, it barely sounds like a tube preamp. Good sound stage and air, much more neutral sounding, recovered some of the top and bottom end I felt I lost with the CJ PV-14 in my system.
Adcom GFP-750: Better than either of the Classe preamps I've owned. Doesn't sound at all like a tube preamp because its not a tube preamp. Compared to the AR LS16 it has very solid bass slam and extended highs, maybe just a little "bright" especially compared to the tube preamps and no midrange warmth at all, not quite the soundstage or the ability to separate the instruments like the AR LS16. I am still very impressed with the Adcom but I wanted more of a tube sound and even though the AR LS16 is fairly neutral, it still has some of that tube magic. For my system, it is currently my top choice but the modest Adcom GFP-750 is a keeper.
Main system components: Cary CD-306/200 192/24 CD player, AR LS16 pre, Conrad-Johnson Premier 11a tube amp, Thiel CS 1.5 speakers. I like the more neutral AR LS16 combined with my CJ Premier 11a for this setup.
In addition to the tube preamps listed above, I have owned Classe CP-45, Classe CP-35, and Adcom GFP-750 solid state preamps. As you can see, none of these are real "high-end" preamps although the AR LS16 is the most expensive (LIST).
Here's a brief summary of my findigs as they apply to my system.
CJ PV-14: Nice warm smooth midrange with good sound stage but slightly rolled off frequency extremes, top and bottom. I won't mention the CJ PV-12 because its been so long since I've owned one I barely remember what it sounds like.
AR LS16: Not as sweet in the mids and compared to the CJ PV-14, it barely sounds like a tube preamp. Good sound stage and air, much more neutral sounding, recovered some of the top and bottom end I felt I lost with the CJ PV-14 in my system.
Adcom GFP-750: Better than either of the Classe preamps I've owned. Doesn't sound at all like a tube preamp because its not a tube preamp. Compared to the AR LS16 it has very solid bass slam and extended highs, maybe just a little "bright" especially compared to the tube preamps and no midrange warmth at all, not quite the soundstage or the ability to separate the instruments like the AR LS16. I am still very impressed with the Adcom but I wanted more of a tube sound and even though the AR LS16 is fairly neutral, it still has some of that tube magic. For my system, it is currently my top choice but the modest Adcom GFP-750 is a keeper.
Main system components: Cary CD-306/200 192/24 CD player, AR LS16 pre, Conrad-Johnson Premier 11a tube amp, Thiel CS 1.5 speakers. I like the more neutral AR LS16 combined with my CJ Premier 11a for this setup.