Tube amps

Tube amps are usually not as good at handling low impedance speaker loads due to their high output impedances. A typical tube amp output impedance is about 0.5 to several ohms, while solid-state amps can have impedances down to 0.01 ohm, depending on many factors including global negative feedback. Because of this, SS amps usually have more control in the bass frequencies.

I have been using a Music Reference RM200 for over four years with my WP7s and have found it to be an outstanding combination. The RM200 has an extraordinary ability to deliver power to relatively low impedance loads, such as the WP7s. In addition, it has proven itself to be extremely robust and trouble free. They can be found on Audiogon for $1.7k to $2.2K.

I have paired WP 5.1 with SF Power 3 before. Despite the power rating, SF Power 3 was not able to drive the WP 5.1 without clipping. WP6 might be an easier load than 5.1, but I doubt it is very different. But if you want to go the tube route, I will suggest SF Power 2 over ARC VT-100 II if you want to stay within your budget.

Tarsando is correct about WP 6 is why the sound lacks warmth. If your goal is to have warmer sound, start with new speaker search.

Of the original options,the PL gear would be the first choice.A VAC Ren series amp is a good match and has adjustable feedback,so damping of the woofer can be controlled.

A few comments in response to the above posts ...

I owned a VAC Renaissance 70/70 Mk. III stereo amp and have owned continuously in my main system for the past six years VAC Renaissance 140/140 Mk. III monoblocks. Even the stereo 70/70 is a very powerful amp that can drive 2 Ohm loads (it is totally dual mono, all the way down to separate power cords and on/off buttons), and all Renaissance amps have very high quality output transformers and beefy power supplies, which are the two things needed for high current delivery. That said, I respectfully beg to differ from the above post on one crucial issue: while the Renaissance amps do have a variable feedback control, if you have to use it, then buy a different amp. Triode amps don't sound right when run with feedback (or more accurately, they sound like just another amp when run with feedback).

As for the PrimaLuna, not even their monoblocks will work properly with WattPuppies because, at 37 lb. per chassis, they do not have anywhere near the kind of output transformers and power supplies required to drive low impedences properly. VAC's Renaissance amps weigh 135 lbs. each and CAT's amps weigh 192 lbs. each for a reason -- very heavy-duty, high-quality output transformers and lots of power supply capacitance. With the possible exception of Antique Sound Labs, all of these cheap Chinese tube amps are indeed too good to be true.

With speakers that need a lot of current like WattPuppies, it is possible to do solid-state amps on the relative cheap and still get good sound and proper bass control. With tube amps, however, there is no way around spending a lot of money because the output trannies and power supplies needed to do the job are extremely expensive (for example, the 70/70 cost $14,000 ten years ago and the CAT stereo amp costs about the same).

Will a given tube amp work on a given pair of hard-to-drive speakers? If it takes two people to pick it up and it costs as much as a new Honda Accord, the answer is yes.