Any significant differences between Siemens CCa and 7308 tubes of the same era? I know the CCa is highly regarded, hard to find and expensive. Seems the Siemens 7308 is a bit easier to find and slightly less costly. Does the 7308 give up much in performance? Thanks!
I'd opine that in most systems a good 6922 or 7308 will suffice. To fully appreciate the nuances of Cca, the other system components must be a very high level.
I use a pair of Cca in what many users would call a reference phono stage. Yes, and as Grant says, the presentation is more refined and the imaging is better but there is a price to pay for this.
I think most users would be totally satisfied with a high quality Amperex 6922 or Siemens 7308.
Today after 5 years which I use two Amperex USN 6922 in my ARC SP-9-MKll preamp i decided to changed among these Telefunken 6DJ8/ECC-88 NOS 100% matched trough my Hickok 539c calibrated tube Test under "Test Load" operation..as you may see at my added link from Picasa (Trusting that all of you will be able to open my link!), as I'm since 1992 a pensioner my gifted ATC SP-9-MKll was received in 2002, this month & immediately exchanged the "Chinese" fitted 6DJ8 tubes, for such NOS Amperex USN 6922 ones when I hear each day 10 hours nominaly...till today still sounding those Amperex ones...but...I think that is time to be changed...my power is also a gifted Dynaco ST-70 from 1990 made by Panor series ll the both units was acquired by my passed away best audiophile buddy during the same day from USA...because last week I change all the tubes in my Dynaco power...today I decided to do the same with my preamp.
Seems me that some of you are really "Gurus"...so please inform me your opinion on these Telefunken tubes & if will live another 5 years?.
The CCa have a top to bottom clarity that is unrivalled in any 6dj8 tube I have ever heard. The sound is wide open and dimensional with excellent deliniation of individual instruments. Midrange resolution and depth is really quite impressive. Clarity, neutrality, extension and the subjective impression of linearity. Not the last word in instumental texture or color (see the Telefunken) and though not hot or bright there is the feeling of a slight treble tilt. The bass may be ever so slightly dry. The depth, dimension and detail of this tube is really pretty amazing.
The E188cc sounds more like an amperex 7308, vivid, colorful with deeper and more dimensional bass than either the amperex or the CCa. The mids and highs are liquid with not quite the openess and clarity of the CCa but perhaps better clarity than the 7308. Perhaps the E188cc has some of the best qualities of both the CCa and the Amperex 7308.
The Telefunken is warm sounding, subjectively dark and compressed especially compared to the CCa but that impression seems to leave upon further listening (you quickly get used to it) and you start to hear the midrange resolution and textures, especially with female voice, string, anything with a lot of vibrato. Liquid and real sounding. The bass seems to go all the way down, perhaps exceeding any of the above yet is on the softer warmer side of things. It is probably the best tube for intimate works and small jazz ensembles though my wife loves it when her feet vibrate during O Fortuna using this tube.
I'm using Porter Ports into Eichman Power cords into a Cayin 17d and a DK Design Signature with Synergistic Research Reference Cables as interconnects and S.R. Alpha Quads Actives into Von Schweikert VR-4 Jrs.
I'm currently using a quad of White Label USA Amperex 7308 PQs in the 17d and enjoying, for the time, the CCas. Sounds pretty good. I think the ultimate call would be CCas in the CD player with either the E188ccs or the Telefunkens in the amp depending on my mood but that will have to wait. Anyway I still like the Amperex to much to let them go.
I would be curious though to see what happened if they switched places and present the 7308s with a cooly accurate and revealing source.
I think what I'm hearing in my current configuration is pretty close to what the 7308s actually sound like through the crystal clear glass of the CCa. Not just pretty good, but mighty good.
Though I wonder where a tube revealing the source leaves off and a tube putting its own spin on the music begins.
Cozva- If you really are using the pre-amp 10 hrs each day, that's 3650 hrs/yr, or 18,250 over 5 years. Most high quality pre-amp small signal tubes are rated for 10,000 hours but of course many run longer and many burn out more rapidly. If the amp stays on 10 hours at a clip, I would think that you would get more hours than average, but the quality/consistency of your AC power is also a factor. Lots of surges, or high voltage conditions would probably stress the tubes and shorten their life.
Audiofeil, how do you spot a great quality CCa by virture of its sound? Would the above description of my set constitute great or am I missing something?
You seem to know this tube, what would you look for both materially and sonically?
>>Audiofeil, how do you spot a great quality CCa by virture of its sound?<<
That's like asking what spinach tastes like.
To my ears the great Cca are very airy, detailed, and impart a "dimensional" aspect to the presentation. You have to listen for yourself and decide; therein lies the rub. You could put 10 experienced listeners with a series of 6922/7308/Cca tubes and more than likely there would not be clear "winner"
That being said, unless your system is up to the task, it makes little sense to spend money on Cca. I would seek out some lesser priced tubes from the same family; they will give you 98% of a top Cca at a much lower cost. I love the mid 60's Amperex Bugle Boy 6922 for example. Andy at Vintage Tube Service sells high quality products at fair prices.
Know your tube vendor. There is a plethora of counterfeit and junk tubes on the market.
A food critic can tell me what spinach tastes like. Sound has much more definable characteristics. Airy, detailed, dimensional says it nicely.
Rather that picking a winner amonst the available 6dj8 variants it might be helpful if the cognoscenti of the CCa in particular could lead the poster and other readers in the right direction. What are the classifications of CCa (date range I presume) and how do they differ in sound from other CCas? I think Andy at Vintage Tube Service could sell a lot more tubes, especially CCas if from these postings people really knew what they were getting. The mystery surrounding this tube is over the top.
An often overlooked Siemens and Halske Tube is the 1960's vintage ECC88/6DJ8. Extremely rare to test one that is not tightly matched between triodes. Just as rare for this tube to be microphonic and even the slight bit noisy. To top it off, no slouch at resolving low level detail, extended on top and bottom. My first choice for sensitive gain stage use in pre-amps.
>>11-05-07: Anacrusis A food critic can tell me what spinach tastes like. Sound has much more definable characteristics. Airy, detailed, dimensional says it nicely.<<
Those are nice words. Unfortunately, there are no universal and accepted meanings for them. I suspect most listeners have their own personal definition of them based on the equipment they've heard.
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