And to save time I include here a segment from his site on the varying differences in sound style between brands..
"OK, SO TELL ME HOW THEY SOUND!!
A tough question if there ever was one! The best advice is to get a few types and hear for yourself the good sounds you have been missing. All of these vintage tubes are excellent, much better than the Russian or Chinese yuck that is being made today. When replacing any stock Russian, Chinese, or East Europe tube with any of these vintage NOS types, you will notice immediately that the midrange glare is gone. Gone too is that honky, boxy quality, and the tiring upper midrange screech that current production tubes are famous for. Here are some VERY GENERAL observations about some of these vintage tubes:
TELEFUNKEN, SIEMENS, VALVO, LORENZ, and other German made NOS: These tubes are usually characterized by an impressive open "air" at the top end. The soundstage is large, even in mono applications these tubes have a great 3-D image. The midrange is ruler flat, and the bass is tight and accurate. These tubes have a fine sense of dynamics, and most are impressively quiet. These are not "warm" tubes, and to some ears their lack of midrange warmth may be heard as bright. I tend to think of them as accurate, and their clean, focused sonic image is astonishing. My personal favorites. The top types are as would be expected: the 7308/E188CC, the Cca, and the 6922/E88CC. The Cca is a very special 6922 made for the German government for telecommunications. They are excellent tubes, as good as any 7308. By the way, the 1970s versions of these brands are excellent as well, in spite of some trashing on "Some Guy's Tube Lore" and other web pages. Don't let anyone tell you what tubes you should like and what you should not like!
AMPEREX, PHILIPS, MAZDA and other Holland/France/Belgium made NOS: These tubes are a great balance of a clean, airy top end, nice midrange warmth, and accurate bass. They are very pleasant, clean, and musical to listen to in hi-fi applications. The white label Amperex PQ type or USN-CEP (same tube, the USN was made for the military) made in the USA are considered one of the best 7308 or 6922 types of all ever made. The D-getter and pinch waist rare types are also highly regarded, and are very quiet as well. The orange label types run a close second. Look for the white label USA and Heerlen Holland factory made for other brands. They are the same tube and usually less expensive than those with the Amperex or Philips label! Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E88CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex is not available, since they sound and look the same. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of the very few worldwide tube dealers to offer these rare NOS French Philips tubes.
MULLARD, GENALEX, BRIMAR, and other British made NOS: Like a warm British jacket of the finest tweed, these glorious tubes have an attractive sweet warmth in their midrange and lower regions. The top end is silky and pleasant, without being rolled-off. The best of these tubes retain a fine sense of "air" at the top, and the upper midrange is smooth and liquid. These tubes reproduce the human voice, especially female voices, with haunting realism. The 1970s Mullard made have an attractive sparkle at the top with the rich bass, and these tubes are usually priced less than the older types.
RCA, RAYTHEON, GE, SYLVANIA, and other USA made NOS: This group is very diverse. The older RCA, GE, and some other brands of 6922, 7308, and 6DJ8 were often made by Siemens, Mullard, or Amperex, and usually are a bargain. The USA made 1960s vintage 6922 and 7308 are nearly always made for the military, although there were some early industrial versions made by Westinghouse and other brands. They are fairly good and usually priced very low. Their sonics are reasonably well balanced. The 6DJ8 tubes made in the USA, and the 6922 or 7308 USA tubes made AFTER 1975 are generally best used in test equipment that calls for them, as they are not particularly attractive audio tubes. The earlier 1960s versions are somewhat better, including the greyglass GE. Their prices are usually very low, putting them on par with the Russian or Chinese types. You may want to try them if on a strict budget, for they will surely outlast several sets of current production tubes, and probably still sound better than the Russian-Chinese trash. Overall, the USA made tubes are a nice surprise with their low prices as compared to the European types."