Siemens -Halske 6922

My Siemens 6922 listening experience with ARC gear is extensive and the answer is simple: in a revealing system, good well matched examples (see below) smoke current Russian 6922's in almost every respect - detail, dynamics, imaging and transparency, among other things. Getting there, on the other hand, is another story. Siemens 6922's come in at least four versions that I know of and the vintage is also important. The four versions are, in ascending order of sound quality, ECC88, E88CC, 7308 (=E188CC) and Cca. In terms of vintage, strictly speaking, the name "Siemens Halske" refers only to the older production tubes from the '60's, while the later 70's/80's versions came in boxes labeled "Siemens Rohre". I have also seen military versions of the E88CC and 7308 labeled JAN or with a falcon logo on the tube. In terms of sound, though, the real distinction is between the getters: the earlier reputedly better sounding versions have a grey chemical coating on them - 'grey' getters - and the later ones have clear metal ('silver') getters. Good well matched examples of grey getter versions are now almost impossible to find or assemble; 70's versions are still around and I highly recommend them. Testing and matching is critical; I wouldn't go into any NOS tubes without my own tube tester. The first and simplest test is for output level, which is measured as transconductance, because the output of every tube declines with hours of usage. 6922's have two sections which have to be measured separately for output. Unbalanced gear often - not always -employs these tubes in pairs with one tube to a channel, so that the aggregate output of each tube in the pair should be the same ('matched'). Balanced applications generally require that each section of each tube have the same output(!) The next issue is microphonics, which is a particular problem with 6922's; it can be due to a manufacturing defect or from mishandling (these tubes are 20-40 years old). The crude way to measure is that you can hear it by tapping the tube while the gear is on; some testers (Vacuum Tube Valley ("VTV"), Hickock 539C) allow you to listen for it. Microphonics is less important if the tube is not used in a high gain application, but I personally would not use a microphonic preamp tube in a cutting-edge system. VTV has also developed a test for triode to triode plate balance. Current production tubes are not spec'd to have balanced plates, but premium NOS versions were, so I believe that test is also useful. This is a long primer, perhaps, but I learned most of this stuff the hard way. Happy tubing!

That's an excellent response from Arahl. I have to say, though, that I had pretty good luck locating CCa grey plates within the last couple of years. I used them in my preamp with good results.

For a softer top end, try Mullard, particularly the tubes made at the Blackburn, UK plant.

Nice Arahl. I was talking to another tube expert who has been explaining some very interesting things. Here's some of his points:
Siemens-Rohne Cca not nearly as good as Siemen-Halske
Siemens_Halske between 59 to 72 are the real deal and are the way you guys have described.
Andy (Bowman) was saying that, believe it or not, the Amperex Bugle Boy 6DJ8 (yes they did make that tube) is quite incredible. Liquid and toasty and a whole bunch of other accolades. Obviously listening and preferences are the way to go, so I will keep you posted with my tympanic experiences. Thanks again guys

Tvad, sorry for the aside e mail. I don't know what came over me. I forgot all about this thread.

I presently have six of the 60's CCa sweethearts in my BAT VK-D5. When I owned my ARC SP9 and SP14 pre's: they were also equipped with the same. The most musical/accurate of the family(if you purchase the 60's version, as mentioned above). The 70's tubes pump razor blades through the system(I suppose some solid state lovers would call that, "detail"). I've also used the E188CC, and found them quite nice. A good place to shop:(http://www.audio-tubes.com/) VERY knowledgable/dependable!!

Siemens-Rohne Cca not nearly as good as Siemen-Halske
Siemens_Halske between 59 to 72 are the real deal and are the way you guys have described.

Warrenh, be careful. My first experience buying the siemens CCa was not good. I bought a NOS NIB pair from a member here on agon. He told me they were made in the 1960s. After listening to the pair of tubes, finally in the correct row of importance of my Sonic Frontiers Line One preamp, I discovered the highs sounded a little rolled off bass a little light weight. Turned out this pair of CCa were from the 70s. What to look for, the 70s tube uses a small round support rod to support the hallow getter.

The white label Amperex PQ 6922 USA made tube of the middle to early 60s will blow the 70s Siemens CCa tube away hands down.

The early 1960s Siemens CCa (all grey plate) is another story. As other have said a great sounding tube. The later 60s Siemens tube sounds as Virgo_ref described, still not too bad a sounding tube I never noticed the brightness, but it just lacks the fullness of the midrange of the earlier CCA tube.

The real deal
http://gon8.audiogon.com/i/c/f/1115367414.jpg

For the money, JMHO, you can't beat the white label middle to early 60s USA made used Amperex PQ 6922 tube. I just recently picked up a used pair made in 1965 for $42.50 on ebay. They test like new, and are dead quiet.

That brings up another subject. Buy a decent tube tester.
jim