$3500 floor standing speakers used. What would be your choice ?

Everyone will have their favorite speaker brand. Mine is Tannoy. There are frequently lots of tempting (to me) used Tannoys for sale.

I’ve used Tannoys with lots of VAC components for many years now. In the bigger system I have Canterbury GR with VAC Master monos & preamp. In the office I’ve used Glenair 10’s (I swap these in/out with Canterbury SE), with VAC Statement 450S amp. It’s quite a price disparity, but a great match. I got these Glenairs used from TMR several years ago for $2000. For $3500 you’re not quite to Kensington money, but maybe close-ish (SE). Turnberry SE should be in range (current line is GR; prior SE models are very good). Maybe you could swing modern Legacy Cheviots. Avoid the DC10A, which are frequently heavily discounted - great looking model but I don’t know WHAT the engineers did to that poor speaker (crossover)? There are older 90s / 2000s models which are exceptional for the money too - e.g. D700. And of course the many vintage options, which Tannoy is known for!

It’s either your sound, or not. The other speakers I’ve heard and liked (but not enough to change!) are much more expensive than 3500 even used: Magico S1, S5, Acora, Sopra 3, Von Schweikert VR55-Aktive, Audio Physic (forget the model but it was $14K+ and had a cone tweeter). I didn’t like Magico A3. Nor the really expensive Vons or Focals. The Magico S1, ueven Mk 1 used doesn’t quite get to 3500. Maybe some of the Audio Physics would get there.

Maggies are notorious for soaking up power - op's tube amp is doing 60 Watts / ch on a good day (fairly optimistic for a push-pull pair of EL34).

But no one so far describes the sound of their recommended speakers.

At the end of the day, people choose their favorite speakers because it sounds most like "music" to them. Which means different things to different people.

In the case of Tannoy, it’sa bit complicated becasue the actual sonic balance can vary wildy from model to model - you’ll have some that are dark & thick, others bright, and everywhere in between. At its core, the "dual concerntric" driver is their claim to fame, and for me, IT WORKS. You get a 2-way "point source" driver that is wholly coherent and symmetric in the uber-critical critical midrange. You can cover "full range" sound (or almost, at least) from a single 10", 12" or 15" dual concentric driver alone - and this is a true "point source" approximation. Though, some Tannoy models add a dedicated woofer.

Look, I waded into speakers over from head-fi / headphones as a young man, circa 2000s, and it was hard for me to like most of the multi-driver speakers I was hearing. Compared to the perfect coherence of headphones (which are generally full range single-drivers), many of these speakers sounded a complete mess on complex music (especially loud rock / metal) - with imperfect combination of the drivers in critical midrange, and with completely separate woofer sections you could always pick out (side firing, down firing), etc. Room issues added on the the problems, but here too - Tannoy’s controlled dispersion makes them much more room friendly. The old trope of playing Diana Krall / etc to demo expensive speakers was true - you HAD TO play that kind of material, to hide the mess on anything more busy.

When I first heard a Tannoy DC it was just a compact floorstanding model (Eyris DC3) but it blew me away. It sounded much more real, natural, coherent. And the imaging was wonderful - 3D and holographic (my first taste of what that meant).

With a good Tannoy implementation I get perfect coherence and "musical flow", from bass all the way through treble. Bass in particular, is always perfectly integrated for the single-DC driver models. (like the larger Prestige series). Other high-end speakers have gotten a lot better about presenting a coherent, integrated sound, but Tannoy will always be my love. And sometimes I still hear a discombobulation in other high-end speakers, and cringe (happened to me with Magico A3). I’ve also never liked the super-large Vons or Focal Utopias - I guess that’s just too much space for the drivers to be spread out over, for me (I like some of the smaller models).

Anyways, within Tannoys they have different themes:

• Pepperpot / Alnico DC (upper Prestige) drivers have a much more vivid, vibrant sound quality, especially in midrange. Extremely detailed. However, the older versions before GR series struggled a bit in upper treble, hence the supertweeters. GR series went a long way to extending and smoothing the treble. These drivers are MUCH more expensive.
• Tulip Waveguide - these drivers are more affordable, and still very good. They’re not as vivid and brilliant and articulate as pepperpots, but their upper treble is typically more smooth and extended.
• Big 15" DC gives a LARGE image size and a very impressive, tactile sound
• 10" DC is a smaller size image but perhaps sharper / tighter, and can be a little lightweight in bass without an extra woofer.

@mulveling - I am genuinely curious about your post concerning phase errors in multi-driver speakers. I was reading Floyd Toole's book on Sound reproduction and he makes a point in that book that phase errors in normal full range systems are not usually bad enough that it has a noticeable impact on the sound quality. 

I am not good to explain this, as in the end it really boils down to "I like what I hear with Tannoys". Phase coherence (at the crossover) is only a theory or possibility for why some of us particularly gravitate  to Tannoy DC sound - Tannoys are NOT time aligned, and only phase coherent at the crossover point, but this may be enough? Its symmetric, controlled dispersion is another possibility - this can reduce the impact of a room's acoustics on resulting sound. I also like a "mid-field" arrangement with my Tannoys, which reduces the room's impact even further. With large multi-driver speakers you cannot get so close or the image "pulls apart"! Tannoy's image is clean and lifelike at almost any distance. The supertweeters can sacrifice a little bit of this coherence, but that's another topic and set of pros/cons. 

The key result is that when I listen to something "busy" like hard rock or metal, it has to maintain the musicalilty and a natural "flow", without feeling like it's falling apart or the musical elements are fighting each other. When I do like other companies' speakers, they tend to be simpler, smaller arrangements like a 2-way with the tweeter and smaller woofer close together. An example would be than Magico S1 and Acora SRC-1. These have great, liquid musical "flow" and I really enjoyed listening to them. Sure, I'd love if they had better bass extension and impact, but when you go to larger models - I hated the A3 and did not really enjoy the larger Acoras (including the $200K one) that much. That A3 in particular sounded like it had a Home Theater sub in it (thumpy, out of time, easy to localize), and I hate that - this always punches me out of being able to enjoy music. Yes, room interactions can cause this but I've never heard anything at all like this from a good Tannoy model (to be sure, some are better than others). I did like the S5 (heard it back when it was an Mk 1), but still the S1 may have been more musical. 

phase errors in normal full range systems are not usually bad enough that it has a noticeable impact on the sound quality. 

"Usually" leaves a lot of gray area, and we are all individuals to "some" extent :)