UPDATE on the Journey: I received my amp with Groove-Tube 6550 tubes and put it in my system. It sounded great, but like many I was itching to Tube Roll. I sent Email to Andy, but never received a reply. I read about and watched the Upscale Audio site but never called to order anything. My Amp Tech recommended some UOS (Used Old Stock) Sylvanias stamped as AMPEX on Ebay, so I bought them for $325 for (4). Put them in and Amp sounded great. Sadly it Red Plated on one tube, and had to go back to the Tech. Now I am told the Tubes are VERY Used, and likely will return to the Groove Tubes. I Called Andy at VTS, and had a delightful conversation. I am considering a NOS set of Tung-Sols or GE Pre-Microwave Division (Per Andy) for about $800. I also have ordered a set of British Military 6550 equivalents the 12E14 tubes for a song (Less than $200), as NOS. I plant to have my tech review and install/bias them to optimal settings here soon. I am hoping the 12E14s will really shine and might keep me from spending the big $$ for NOS GE/Tung-Sol.
jeff in Detroit