Audio Research Ref 5 preamp

Compared to my old Ref 3 it has tighter bass and plays complex demanding passages more cleanly. I guess I would call it more " precise". To me it was worth it but some might prefer the Ref 3's darker character. - Jim

Kclone - I assume you mean original US-made Tung Sol 6550s, which run fine in ARC power supplies. I also think they sound better there than current Russian tubes do. The original Tung Sol puts out a bit less power than a 6550A or 6550C (35 watts as opposed to 42, I believe), but I don't think there is much question that they were the best sounding 6550's ever made.

yeah, I have the American version. I originally bought them for extra tube for a Cayin KT 88 (was using 6550s in place of the 88s). Okay, then I will drop the Tung Sol in the ARC REF 5. Thanks for the helpful response.

No, I stand corrected. My Tung-sol 6550s were made in Russia. Even so, they sure sound pretty good to my ears.

I too am a happy owner of the Ref 3 preamp, but I also intend to wait for the Ref 7 preamp which will undoubtedly be audibly superior to the not-yet-released Ref 6 preamp. :)