NOS E83CC, Triple Mica, Siemens&Halske.

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E83CC is the designation for the studio version of ECC83. Standard ECC83 has a data sheet with only "typical" numbers, and there is no standard what is acceptable or not. E83CC however, has minimum and maximum values for all important data, and also a test instruction how to determine "end of life" limits. Moreover, it is a long life, low noise version. People call it a triple mica tube, but in fact it is a four mica tube. I will explain it in the text below, what that is for.

Sometimes I get a call or an Email, saying do you want to buy tubes? Most of the time people are trying to sell a private tubes collection, most of them slightly used, many boxes missing, and just a few of type each. Specially when these are 100's or 1000's of tubes, price expectation is unrealistic high. Such collections are very hard to sell.

It is really rare to be offered something nice for a reasonable price. In 2024, I was contacted by a circuit designer, who worked for the German company Experience Electronics, at the time when this company was still in business. The owner, Werner Haas has since passed away, and his company was shut down. The developer is retired, and during final inventory, these excellent Siemens&Halske E83CC popped up, in a forgotten box, and then he called me. Sometimes it happens :)

What makes E83CC so much better as the standard tube, ECC83

It is not a matter of just writing the more expensive type number on the tube, like is common practice with the Electro Harmonix company. It also requires improved hardware, and a more detailed data sheet, listig the performed tests. an E83CC is ony a real E83CC, when it complies to vintage data sheet, and all test are done, and done the same way.

 

Data sheet copy here

Specifications according to the German data sheet:

These very rare tubes are often referred to as TRIPLE MICA normally, but I noticed they have FOUR mica plates actually, of which the middle two are attached to each other.

The tubes have the old Siemens & Halske brand, as in the middle of this picture.

At its time, E83CC was the Siemens answer to the legendary Telefunken ECC803S. We see the E83CC also from Valvo, but the small printing has the S&H special sign. (Letter H on it's side). Telefunken used a so called frame grid, to reduce the microphonics. Siemens went another way, with a so called triple mica tube. To explain this, let's call the bottom mica the first mica. The second mica is then on top of the tube, and normally a tube would be finished by that. First and second mica are specially treated, with minerals and heat, after which they mica gets a powdery gray appearance. This causes the mica layers to separate from each other, on microscopic level. The mica plate is still in one priece, while the isolation properties have improved by this. At the same time, the mica has become softer, at the places where the grid as cathode go through the mica. This is the first step to resonance damping.

Then, on top of the second plate is the third mica attached. This is a thin, transparent mica, with special carvings, forming a spring. It has not been softened, because a spring effect is needed. This mica is cut in such a way, that it forms two small springs, which rest on the cathode sleeve, as a damper. This is preventing microphonics.

In 3mm distance above that, the fourth mica is attached. It gives additional stability to the system, but it's main unction is to keep any getter flash away from the tube system. Such traces if they are formed at an unlucky place, can cause noise. With this fourth plate, any such traces will attach to it, and wdo not harm there.

This construction belongs to the best there is, but difficult to manufacture. It is found with few tube types only, and those that have it, were made in small quantities only.

Here you can see the mica damper plate. On the picture you see this "Z" like shape, the left end rests on the cathode sleeve. (Just above the "S" letter of the word Siemens). If you click on the picture, to enlarge it, you can see the plate in the middle, consists of two plates attached to each other. Such a beautiful tube. I think you can not develop this technology any further.

This is the etched printing.

In the middle is the ≠ symbol, which stands for Siemens & Halske, Munich, Germany.

What I like so much about etched printing, I have not seen this faked yet.

More info about small printing

The tubes are all from the same batch number, which is 373.

Matching.

The tubes are supplied with an AT1000 computer test report. It is unbelievable quality. I verify it of course, but I can take just two random tubes, and chances they are a perfect pair almost 100%. Even Telefunken ECC83 does not even come close to this. So far, I have only seen this with Tesla E83CC, of which I opened the sealed master carton myself. For the rest, I have never seen this before. With low gain tubes yes, but not with a high gain tube like E83CC (or ECC83)