Siemens ECC81 Triple Mica-how to know which one is a Triple Mica?

[Audioexcels]

I have asked about 20 Ebay sellers if their Siemens ECC81 is a double or triple mica tube and I have received 2 total answers, the other 18 never responding. Heck, I got a response today saying as you can see, they do not have a mica??? I never knew "any" 12AT7 tube had no micas???

What is the best way to figure out how many micas these triple mica versions are?

Thank You!

 

[analog addict]

Count them. These tubes will typically have 2 mica layers, one below and one above the plates. A triple mica tube typically will have an extra mica layer separate and above the normal top layer....

 

[zandru]

What is the best way to figure out how many micas these triple mica versions are?

It is the mid-60's Siemens E81CC's that are said to be the best ECC81 / 12AT7 type tubes
to have been manufactured. Having 3 mica spacers. Two main mica spacers hold and
center the "elements" package within the tube, while the upper mica spacer stabilizes the
Halo getter mounts without touching the inside of the tube. Most E81CC's have grey plates.

 

[Andyman]

Go look up a triple mica 5751 on eBay to see what one looks like. Like said above it's a third disc 1-2mm above the top disc. I'll post a pic of a 5751 later on.

Never mind, Zandru has it all covered.

FWIW though, I did see auctions out there for "triple mica" with only 2, so look at what your bidding on closely

 

[audiodon]

The plates are vertical. The micas are horizontal and sandwich the plates on top and bottom. The triple mica ones have an additional one on top for rigidity.

 

[gearhound]

Generally, triple mica tubes tend to sell for more $$$, than the more common 2 mica variety.

Steve

 

[zandru]

Adding a piece of mica to the getter mount to further stabilize the getter is a thoughtful scientific approach to produce a superior getter flash,
which improves the tubes longevity and overall performance. Any noticeable benefits by adding additional stabilization to the getter is pure
German electronics ingenuity at It's finest during Audio electronics Golden age.

 

[zandru]

look at what your bidding on closely

Greetings to Audioexels, AK'ers & Andy,

I myself catalog and study wEpay photos of tubes and other electronic related Items, also from other sources,
and I tell yah!, those wEpay photographers haven't the "EYE" for taking the correct types of descent photos, It's
a shame and disrespectful to the buyer considering all the business they do and the $$$$'s they pocket. however,
I have seen some rather well pronounced getter flashing that has passed way below the dome of the tube and
when photographed from straight on, blocks the the top halo getter mica from view. Like you have said Andy,
look at what your bidding on closely. Also It's a common practice for me to message the seller and request to
see additional photos based on what I'd like to see. If the seller does not or can't add extra photos to the listing.
You could recomend an email address that they could send the photos to. Remember, "You are the Buyer,
the one with the Bucks" you call the shots.

 

[Audioexcels]

That above photo really made it clear and I wish I had made this post long ago. I can clearly see this in most listings I have viewed and from what I can see/find, these are indeed the more rare finding as most have only 2 micas.

I agree about what has been said regarding the testing on these tubes. One thing I appreciate about one of the stores I have seen online is when looking up the GEC A2900's (cough-price), they mentioned that one of the two tubes had some microphonics in one of its sections and I thought that was good of them to say since many probably don't bother to mention this in spite it's a load of money to cough up.

Even at the price the triple mica Siemens go for which I have seen at even $30 recently, if they are microphonic or do not test as stated or something not good about them, you are out $30+shipping which may not sound like a lot, but to me that's no chump change.

Thanks a lot for that graphic shot of the third mica. I may just pay the premium online since at least I would have a much more reliable resource than a random person in Europe just wanting to make quick bucks.

On a final note, why is it these sellers just cannot answer a simple question is beyond me, but thanks for the mentioning to just ask for more photos in the event I cannot make out a possible third mica.

Cheers all!!!