Amperex 7308 vs Siemens 6922 sound differences

Oh boy, an area where I have some actual experience:

I've used some of the above mentioned tubes and can offer these observations:

The Amperex USA White Label 7308 tube was dynamic and textured with good bass response. A good tube but seemed to have a high frequency ceiling and seemed somewhat closed in compared to the Siemens. The bass was good and though perhaps not as tight as the Siemens, it had substance. One day I may want to give this tube another try as no one seems to agree with me on it's sound.

The Siemens CCa sounded as most Siemens sound: linear, crystal clear, transparent with tight transparent bass. I'd agree with coolish, perhaps slightly antiseptic over-all. The midrange has an almost solid state quality but slight. Don't get me wrong, this is a tube you will want to keep in your collection. What it does, it does like no other and I would put it in the first position of amplification. Go with clarity up front (like your source), because once you've lost it you can't recreate it further down the line. Do you know what I mean?

The Valvo E188CC red label (which I have heard was their premium line) was a marvelous tube: powerful, dynamic, great bass liquid mids (relatively speaking) and extended highs. More colorful than the Siemens, I'd say, like the Amperex but better overall.

The Telefunken: Be careful of this tube <> on the bottom or not. Telefunken produced tubes that had two totally different sound characteristics. 1)Warm and soft to the point of putting you to sleep and giving tubes a bad name and 2)Neutral, extended response with deep and tight bass and the most natural presentation that you are likely to hear from any tube. Neither version by any stretch of the imagination,like a Siemens at all as is reported by a popular tube vendor. Unless you have really have done your homework, and I thought I had done mine, I would only refer your purchase of this tube type to an expert. Maybe a German vendor.

I ended up with a set of Ei 6DJ8 A frames, which is supposedly a copy of some famous Amperex or Siemens. Gorgeous! I think the reports of Eis going microphonic is a lot of hooey. One day (after the recession) I will purchase a pair of Siemens E188CC which I feel may have a bit more body than the CCas or if I can id the real deal Telefunkens, a pair of those.

Actually quite a number of sellers handle USA made Amperex(PQ) 7308s, Kevin being one of them: (http://www.upscaleaudio.com/product.asp?itemid=100&catid=42) If you want a treat, find some Siemens E188CCs for your CDP. A step below the CCa, but still provide excellent soundstage, transparency and tighter bass than the PQs (http://www.upscaleaudio.com/Siemens-E188CC7308_p_611.html).

I am uncertain and think that Amperex was not a maker of a tube they boasted as a 7308 I do know of some of their 6922s. Amperex was a Phillips product and while originally based in Heerlen Holland Phillips the parent company bought out a number of other manufacturers including Mullard.
You can buy an Amperex from Hicksville long Island USof A a British Amperex . German Amperex one or one made in Holland. The 7308 is a premium select member of the 6922 production. In any event the variety of Amperex tubes around due to age and origin make it impossible to be at all certain what tube you really have.
The nation of origin was applied by Phillips at their discretion without regard for the actual nsource. On top of all this Amperex has to be one the most copied, knock off tubes, found on the market.
Whilst only a small time tube collector, I just don't recall a 7308 from Amperex, my gut says something is not right here.
The Siemens West German tubes came in a couple of flavors as well but the vast majority are Simply Siemens/Halske Rohrer (tube) and are very good tubes in terms of linearity, they keep their cool and rarely if ever get loose. I also find them well balanced thruout the spectrum they are really consistent. Some just don't want a tube this clean sounding and is a bit cool.
I found that despite it's seemingly gratuitous role in a CD player the tube you choose has a very audible impact. I ended up with a Amperex USA as my favorite for this application but liked the relatively recent vintange Siemens 6922 almost as much but more sterile and also would roll a Mullard CV2943 which sounds a lot like a German tube believe it or not. (hard to even source today but I think Kevin Deal had some recently.)

Keep in mind that it all depends on the vintage of the Amperexes or Siemens involved. I tried both white label USA Amperex 7308, and West German Siemens 6922. I would say that there is a significant difference in sound quality, but not one that I would call better. I personally have never been as much of a fan of the Amperexes as some are. I find the Siemens to have a similar overall tonal color (that's not a negative), but a little leaner, with a little finer delineation of high frequencies, and maybe a little faster sounding. The Amperex gave me a more robust sound. Images a little more fleshed out with very stable imaging. But overall, they made the Tjoeb sound a little less modern and a little reminescent of vintage tube equipment; not necessarily a bad thing. Both are very good tubes, and much better than the stock Phillips. My very favorite by a long shot has been the German Telefunken 6dj8. Beautiful, wide open sound, with great tonality, and soundstaging. If you ever look to buy a pair make sure that they are real Tele's with the <> on the bottom. Sometimes they are rebranded Siemens.

Keep us posted.