Difference between Siemens CCa & 7308

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?

Thanks,

Anacrusis

>>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.

Audiofeil...

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.

The only Siemens CCa to own is the grey riser version from the late 50s through mid 60s. Period. Big air, big soundstage, deep and tight bass, and wide image.

Otherwise, one might as well buy Siemens E188CC (7308) or E88CC (6922), which are excellent in their own right, and less expensive than CCa versions with shiny risers or thin getter supports.

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.