I'm using the groove tube mullard reissues too. They vary in sound from one tube to the next. Some sound unbelievable, others can be thin sounding or fuzzy sounding. I went through five tubes to find three to get the sound I wanted. I tried out RCA blackplates, Telefunken smoothplates, plus the originals. You could take the best properties of all these tubes and combine them into one tube and the Groove Tubes is still better. The originals compete well against the NOS tubes, but its no contest against the groove tubes. It's important to get the good ones. Combine them with a wilson benesch tonearm and the accuracy is amazing.
thanks for all your responses.
I use Philips JAN 5751 in V1, 12AX7 Tele in V2 and 12AT7 GE in V3.
Mingles, Dan Meinwald is the EAR USA rep. To my knowledge, Mitch does repair work.
Telefunken 12ax7s, but also tried the JJs and they are great too.
I'm using Groove Tube Mullard reissues and like what I hear, but many people say Telefunkens are the best. Mitch Singerman (EAR U.S. rep) recommends JJ's.

Here's an old forum worth reading: EAR 834P tube swapin