Chris,
I purchased plenty of tubes from Andy. He thoroughly test his tubes.
I have plenty of Mullard 5ar4 tubes, fat base, older double o getters. They are very robust, but are a little cool sounding compared to something like a Mullard gz32.
In my preamp I like the sound of the Brimar and Philips 5r4gy tubes. They are directly heated, which can be hard on my 6sn7's on start up.
Thats why I'm interested in the 5z4gy tubes which are indirect heated.
