best 5-20K speakers for high-end tube amp?

May I suggest build your own speakers?
Since you are in China, finding the right folks to build speaker cabinets for you would be quite easy.
For starters, I would recommend the vintage EV 12TRXB and Jensen CX-120 coxial drivers.

This is what I build for myself:
http://mysite.verizon.net/vze7qf7h/cx120.html

Here is a link on the ev 12trxb

http://www.geocities.com/tadgesualdo/12trxbmanifesto.html

One of the most sought after coxial is the Jensen G610 drivers.

With these speakers, you don't even need expensive audiophile speaker cables any more.

That's a great suggestion. I can't access your site from China (geocities is censored) on this computer, but I'll check it out soon.

I don't wanna put a lot of time into it though, this recent 'hifi obsession' is dominating all my free time now, seriously eating into other priorities..

I'm surprised those cables wouldn't still be useful. I guess you mean that with sensitive speakers, it wouldn't matter so much if the speaker cable degraded the source signal?

I've been experimenting madly with power cords on my CD player and preamp, and find they make a remarkable difference. I know there's huge debates about impact of power cords, and this is my first experience A/Bing them, and I find it hard to imagine people wouldn't notice the difference given a revealing enough system. My Isoclean Focus cables are practically unlistenable they compress the sound so much (maybe i shouldn't have said that, now i plan to hawk them on audiogon :-)...ok, we could say they add a certain rough texture/flavor to the sound, which actually sounds better on some instrumentation through exaggeration..plus synergy counts right?), I'm so glad I got these Siltech G6 cables on a risk, they really open up the sound. I've discovered now that without them, along with the Kondo speaker cables, my system doesn't have its magic.

btw, i think i'm gonna change my username, not that i'm hiding anything. i wanted to change it a while ago, but had all these threads going. since i might start transacting on audiogon, i don't wanna get stuck with a username i don't like...it's plainly obvious i'm an audio slouch compared to everyone around here...

Hi been away.

Sold my Avantgarde Duos and bought a pair of Hyperion 938, my budget was $15000 but got these as an interim prurchase for $4000. Never regretted selling the Avantgardes once. Suddenly I had bass I had TONAL COLOURS with great inner detail NOT JUST WARMTH. A soundstage was suddenly once again apparent. It was quite plainly very involving musically. I owned the Avantgardes for two years so I did like them. Had valve amps, solid state amps had the Jadis JA 80's etc. No way does it compare to a good cone design.

Exiting and can be electrifying when set up right, but not a great all rounder and not the most natural sounding by a long margin in my opinion.

If you want it to be electrifying dyanmic and exciting you have to give up a little of the tonal riches which to me make music special. You use a Jadis and yes you get warmth but you lose transparency and a little of the electrifying presence. Their bass is one of the worse I have come across from any speaker and I have owned which include Audio Physic Avantis, Harbeths, Quads, etc.

Just look at the two two intermnet reviewers Steve roachlin and Sjragen, I believe they have both given up their duos for paper cones.

http://www.horninghybrid.com/agathon.htm

No_slouch,
If you like the tube sound, try the Dan a Digital speaker (www./danadigital.com). I'm lucky enough to live in Australia to hear it out ( Aussie made speaker), but not rich enough to have one :(. Don't know if it's available in China, but absolutely you MUST listen to them. Hearing is believing. I never heard any kind of sound that comes as live concert from speakers. Don't laugh but I would have one when I win the lottery.