Need help from Quad ESL 63 owners.

Recommendations on phono cables for the above system?

Could you describe what you experience musically as the system is now? Do you have any problems you want resolved, or just hoping to find a way to upgrade? I have about a hundred questions that can be important to results you may be getting. What are you loading the Ruby 2 at, what is your current speaker wire, interconnect, power cables and tubes in the ARC?

Thanks, Albertporter. I just bought these speakers not too long ago, the rest of my gears have been around for a long time. I love the sound of Quad 63 with classical music, but I find it too forwarding when I first got them. I have since put in a pair of MIT MI330 CVTII from Preamp to the Amp and it made a big improvement. The rest of the IC's are all Ameralds (phono and from phono to Preamp). I have been using MIT MH 750 speaker cables for years and I didn't change them with the new speakers. I wonder if the MIT MI330 CVT made such a difference, should I get all MIT IC replacing my old Emerald IC? The loading for the Ruby 2 is factory-set loading, I believe is 49. My Ruby 2 is MC (0.35), but I am using the MM mode on the phono stage, because I find the volume level is not as big between each division on the volume knob. The tubes on my Classic 60 are Tesla KT-88. Power cords on the speakers are just factory power cords.
Musically, I am looking for natural sound of instruments. I don't listen to big orchestral music, just chamber music, instrumental and voice solo. Thanks again.

I would change the load on the Ruby 2. Begin with 28K and use a good quality resistor. Next, check the VTA on the Ruby, this cartridge should be slightly down in the rear when viewed from the side. If it is too high in the rear, the soundstage is forward as you describe and bright in tonal balance, there is also a lack of focus and dynamics in the deep bass. Power cords on Quads make a big difference, If you can afford to replace them with aftermarket, do so. Also, I do not understand about the MM input on your phono. Moving magnet input usually requires a much higher output cartridge than your moving coil produces. Does this preamp offer both options? On wire, is the AQ Emerald the older version that is all copper? If so, I would not be too quick to change, it's most likely not the problem. Last, what are the input tubes pushing the Tesla KT-88's?

I had a fair bit in common with you - ESL63s,Classic 60,SP-9. I was very happy with the change on going to Goertz MI-2.
Best interconnect (pre/power) I used (of many) was Siltech FTM-4. Also Audio Note worked really well(less detail, but maybe more natural). Dont use my turntable much, but got good results from my Sony CD player after doing LCaudio mods. There really is beautiful bass in those Quads(if limited in volume).