IMG_5102 by Joe Blow, on Flickr So I finally got around to buying one of these. At $70 shipped, it was not an easy purchase, as I'm not made of money, and JJs are cheap and have always served me well. Curiosity got the better of me though. As you may have read in one of my many posts regarding 5150s/6505s of all varieties, I have found the 5751 type tube to be excellent in V1 and, to a lesser extent, in the phase inverter position. I've now tried this in V1 of both my 6505 head and my 5150 III 50-watt head. Previously, I've run JJ 5751s there. I haven't had a lot of time to try it cranked, but I did spend a few minutes A/Bing the JJ with the Philips through my 6505 with the volume at "2" just a bit ago (to those of you unfamiliar with what a 6505 sounds like on "2" through a 4 X 12 cab -- it's LOUD). Honestly, I'm a bit disappointed. Not because it doesn't sound excellent -- it absolutely does. However, I think I still prefer the JJ there slightly. This is probably splitting hairs, but here is what I've noticed so far -- and note, I kept all amp settings the same throughout. The Philips has a little more clarity in the mids and high-end, but not a huge amount. The mids have a delicious grind to them, and the highs have a sheen/sparkle to them. What I notice about the JJ 5751 is it has just a hair more balls in the bottom end and in the lower mids. The upper mids have *almost* as much richness and grind as the Philips. The biggest differences are noticeable on palm mutes. The JJ, I have to say, just has a little more thump, and it's noticeable. When letting distorted chords ring out, I do have to say that I slightly prefer the Philips due to that clarity in the mids and highs. It is a very close call though, and I plan to keep playing with my EQ and EQ pedal to see if there is an optimal setting with the JAN Philips that might yield a superior result -- for example, upping the bass and mids a bit. I guess the disappointment comes from hoping a known "holy grail" tube might be immediately better sounding than a $15 JJ, but it wasn't. However, it will likely last longer, and that's maybe where the value is. I'll keep experimenting.