300B for LS3/5A?

Their impedance should make the Rogers an easy load on the amp, but unless you are wearing your speakers as headphones I don't think your going to be very happy with the volume levels that you are going to achieve. Just my humble opinion.

Some die hards were claiming they are actually a good match! Are there owners out there?

I drive my LS3/5A's with 2A3 SET (3.5W) in a small room with very good results.
If you have a small to medium listening room,300B amp would have no problems.
Bass control and dynamics will not be comparable to a good SS amp,however you will have all the midrange magic of LS3/5A's.
As Mcfarland mentioned above,with 300B you won't be able to go very loud.
All this IMHO.

Will run them but best to match loudspeakers to amp at 11ohm great but 82db 1 watt. Your at the bottom end or far past of what a SET can drive. Might be great for nearfield but dynamic range will suffer. If your sold on the wee BBC monitors and SET look for a 845 or other higher power SET. I see many running loudspeakers that are at the xtreme of what a SET can drive most give up on SET after. Or on forum they go saying SETs distort, have no bass,can not produce much SPL etc etc. Best to SET ;0 up system right from the start. Make sure amp loudspeakers are a good match.

I have heard 300b driving the 15ohm version with very good results even in a living room! But not sure if 11 ohms would make a different?

My personal memory of LS3/5a's (20 years ago) is that they are very colored, in a beautiful way. They emphasize midrange and present it wonderfully. They are shy in the treble "air" and also they have a bump in the upper bass region to compensate for lack of lower bass.

This is kind of also a description of a 300B SET amp, or at least the typical one. Midrange emphasis with great beauty, lacking in air, great presence. Bass might be deep but lacking in control.

SO, on paper this is not a complementary match, but a match with similar biases.

BUT my own experience is that audio gear matching often achieves counter-intuitive results.

I would not have high expectations of this match but have no doubt it would be fun to try :)

And it might work well, quien sabe?

Art

best with push pull.....in many ways, still incomparible.

In my office system I run Harbeth LS35a s with a Tektron 300b SET amplifer (Linn Ikemi and Logitech internet radio/server as sources). The space is quite small maybe 10 x 12 ft. I rarely go past 1/3 volume and it has plenty of power. The sound is beautiful to my ears. Obviously not as much clout and bass as a heavy duty system but that's nit the point - hard to beat for an aria!