I thought I would bump my old thread with a report on rolling the 845's. I have compared the standard Cary supplied 845 with the Shuguang Psvane 845T, and the KR Audio 845's.
Cary no-name 845's: rather thin sounding with the most lacklustre tone of the three. Good dynamics, especially good microdynamics.
Shuguang 845B: AVOID! DO NOT USE THIS TUBE IN YOUR CARY! I have tried this tube on two occasions and each time, the amp blew up. The first time, it actually burnt out a resistor and the bias pot. The second time, the fuse exploded and took out the fuse holder. That's right, the fuse did not just blow - it exploded. I had to remove shards of glass from the fuse holder. It was not a faulty tube - these were 845B's supplied by different people. The base is physically thicker than any of the other 845's, and it is a bit of a tight squeeze to get it into the socket. The internals look to be better built than its more expensive cousin, the Psvane 845T.
Shuguang Psvane 845T: sounds horrible out of the box. Needs 100 hours of burn-in, then this tube REALLY opens up. This is an exciting sounding tube, with excellent dynamics and a wide, deep soundstage. Tonally it is richer than the Cary 845's in the midrange, but the top end can be a little glaring. This is an impressive looking tube - it is physically larger than most 845's, is heavy, and glows very brightly.
KR 845: also sounds horrible out of the box, and needs 100 hours of burn-in. Tonally the best of the lot - the bass, midrange, and top end are incredibly lush and rich, with no hint of the brightness of the Shuguang Psvane. The sound is simply beautiful - going back to the Psvane after listening to this tube is a bit of a jarring experience. Dynamics are not as good as the Psvane. These valves glow very dimly - the Psvanes shine like a 20W lightbulb. The KR 845's emit a dull orange glow.
Best tube of the lot: KR 845 if you like tone, Psvane 845T if you like dynamics.