ARC SP9 MK2 tubes

I have just upgraded, or thought I did, from a Counterpoint SA3 running through a B&K PT3 series 2 pre into a B&K Ref 4420 amp. I replaced the Counterpoint and B&K pre with a ARC SP 9 mk 2. Speakers are Vandersteen 2CE Signatures. CD is the Adcom 600. TT is a Thorens 160 with a Linn Basik arm and Goldring 1012 cartridge.

I really liked the warmth and lack of grain when I ran the Counterpont through the B&K. I used the loudness switch on to gain bass as my room does not yield solid bass response.

When I put the ARC in its place last night, the sound changed quite a bit. When playing te CD I detect some grain and hardness but the imaging and detail are good. Since the ARC has no tone controls, the highs seem to roll off a bit so I will probably increase the highs on the speakers a bit. The tubes are "Grand Dragon" which I guess must be Chinese tubes. Never heard of them.

For you ARC 9 users, what tubes have worked for you and has anyone heard of Grand Dragon Tubes.

I am thinking maybe the B&K and ARC are not a good match. I experienced similar results when I ran a Sunfire reference pre through the B&K. Do B&K amps only sound good with B&K Preamps?

Looking for advice and opinions..

Eagleman