Tube newbie, Audio Research questions?

Give the Nagra VPA 845's a try on your 7's before you commit to anything. The sound runs in between that of the "high definition" ARC's and burnished euphonics of the C-J's. Dynamics up there with the Krells. A particularly syngergistic match with the Wilsons. I'm using them on Sophias and your speakers are more efficient.

WVICK

Why not go in increments. You haven't specified which Krell you have, but why not go with best of breed. Certainly you will probably miss the control, slam, and overall ease and effortlessness of the Krell if you go to low powered tubes for amps, though you most certainly will make up for it in other areas, like naturalness, rounded more 3 dimensional images, etc. It's been my experience that with more (quality) tubes in your system you will experience a new dimension where you get less ss compression in the soundstage and start to hear more of what your WP7 I'm sure is capable of-rendering very believable images not only in a huge side to side stage but front to back with rounded, full form, and "action" as well as bloom and color. Be careful, since not all tubed equipment is created to the level of the Wilsons.

I have to say I stumbled upon a rather awesome combination, with Krell 750 monoblocks in my system last year, I decided to try out a tube preamp, the VTL 2.5, a rather inexpensive tubed preamp that I didn't expect much from. In fact, it completely and dramatically altered what I was hearing in my room with some very high end SS, and Dynaudio Temptations. In fact, many of the comments from above are helpful in relating what is possible once tubes enter your system.

If you go in steps, you can still benefit by keeping your amps, try a preamp (like ARC REf 2, VTL 7.5 or even 2.5, Hovland, Wyetech, and Atma-Sphere etc.) Obviously,the Krells are great amps and though sometimes not considered true high end are very true to what they are fed. Your WP while efficient have a rather rough impedance curve, so power does not hurt in that application.

Also be careful with certain preamps, like the ARC ref 2MkII which sounds almost like the Krell preamps and has a distinctly solid state signature, with some of the benefits of tubes. If you can keep SS devices out of your preamp, all the better. ARC recently introduced FET's to the input stage of that pre in its latest iteration, so again, tread carefully. Also, beware of very tubey sounding equipment as well. Some of the less well designed gear can tend to the overly warm, noisy, grainy, wooly euphonic, sweet (VTL 2.5, CJ,) while some of the newer more expensive pre's like CJ ART, Atmasphere, and the like have minimized much of the negative potential that tubes can bring to the table. The better tubed pre's sound clear, balanced and natural without being fat, slow and losing detail and speed.

Sorry to ramble. Feel free to email me if you want more specifics, as I've played around with Krell a lot and know where you're coming from. If you go with a tubed preamp and keep the Krell, stick with best of breed and have your cake and eat it too. If you want to go further, then take that step when you're ready.

I've spent a lot of time with AR products. I currently have a Ref Phono driving early model Ref 600's through a home brew passive Pre. I found this to be even better than the best Pre. I have also trialled both the Hovland and AR Ref Mk II and slightly preferred the AR, but both were veiled in comparison to my Passive setup. Mind you this only works because the Ref Phono has a very low OP impedance and you need a relatively high input impedance in your amps. Of course if you are running CD then that's another factor.

Bottom line? If you can run Passive Pre then you won't regret it, next best in my experience is AR Ref Mk II ...

However, you will get a HUGE improvement going to good tube amps, for starters real, musical, immediate, 3 dimensional sound (I originally had serious class A SS Monoblocks in the system). As good as they are even the AR Ref 600's are only half way to where you need to go but you don't need to spend a fortune (done that). I've modified the heck mine and improved them out of sight. First you need Chokes in your power supplies and then you have to triode strap the output tubes, the difference is day and night. If you want even better sound then you can't beat good DHT triode amps. I personally like 845's. I bought a pair of 2nd hand Chinese amps and rebuilt them (a cheap way out if you have some technical expertise). The power supplies, driver circuit and OP trannies are everything! Good Luck!