[Oskari]

Quote:

The code of the E33CC was for an item for sale on ebay.

 
OK, I found these
 

1. http://www.ebay.com/itm/Matching-pair-of-NOS-NIB-Mullard-ECC33-tubes-/281032405980 — fX1 B7K
2. http://www.ebay.com/itm/Matching-pair-of-NOS-NIB-Mullard-ECC33-tubes-/281044251955 — fX1 B7K
3. http://www.ebay.com/itm/ECC33-Mullard-B65-CV2821-6SN7GT-yellow-print-rare-/300840596483 — fX1 B7K
4. http://www.tangotubes.com/ecc35.htm — the first ECC33, fX. B.. I guess

 
all apparently fX-coded, possibly even fX1-coded, but they all claim to be ECC33, not E33CC, tubes. All of these are also of the tall-base skinny-bottle kind but the base color varies. Note the 7 that is 1957.
 
Then there are these
 

1. http://www.akh.se/tubes/htm/ecc33.htm — 5K1 B5F
2. http://www.sanyue.net/bbs/read.php?tid=6948324 — 5K1 B5G, 5K1 B6E
3. http://www.erji.net/read.php?tid=1274026 — 5K1 B5E
4. http://www.erji.net/read.php?tid=1260029 — 5K1 B6E

 
all of the short-black-base fat-bottle kind. Note the fives and sixes of 1955 and 1956. There are older ECC33 tubes with Mullard-only numeric codes. Are they all fat-bottled like these 5K1s?
 
The saga continues. Apparently there are also (at least) 5K2s and 5K3s as claimed by the following.
 

1. http://www.ebay.com/itm/ECC33-MULLARD-in-box-new-/130776960452 — 5K2 B7J3
2. http://www.worthpoint.com/worthopedia/mullard-cv2821-ecc33-6sn7-163014808 — 5K3 B7J4

 
Now these are not 1957 codes, so we seem to have arrived to 1967. Again tall-base skinny-bottle tubes with varying base color.
 
Obviously I'm just guessing based on limited evidence but it seems possible that fXs were made only for a while between 5K1s and 5K2s.
 
What are the codes on your ECC33s, everybody?
 
By the way, this thread could use some ECC33 photos.

 

[dminches]

Ok.  What do I have?
 
 

 
 

 

[rosgr63]

They have grey plates so they are of later production.
 
Here ia an early ECC33, short black base, black plates, inverted cup getter currently under test on Glenn's amp.
 
 
 

 

[Skylab]

I have a pair of 5K1, one B5G one B5E:



Then I have a single with a totally different code, 1324 AO. It looks older, has the pan getter (versus the D getter on the 5K1's), and is the only one that came in the old original box:

 

[rosgr63]

Yellow Print
 
 

 
 
Dark Glass
 
 

 

[Oskari]

Quote:

Ok.  What do I have?

 
5K2 B3D5 — 5K = ECC33, 2 = version 2 (of 5K), B = Mullard at Blackburn, 3 = 19?3, D = April, 5 = week 5 (of April)
 
This could be 1963 or 1973 but in the latter case 5K3 B7J4 above would have to be a 1977 tube.

 

[dminches]

Thanks

 

[Oskari]

Quote:

I have a pair of 5K1, one B5G one B5E:

Then I have a single with a totally different code, 1324 AO.

 
1955 5K1s, and there we have the earlier (Mullard-only) numeric type code 1324!
 
I think that's 1324 A0. Others I found online are 1324 B1, B3, C3, D3, E2, E4, I2, J1, J2, J8, K9, L9.
 
Those suggest to me that we are looking at an MY-format date code where A = Jan and L = Dec, and years range from 1948 to 1954. Thus A0 = Jan 1950.

 

[Skylab]

1955 5K1s, and there we have the earlier (Mullard-only) numeric type code 1324!

I think that's 1324 A0. Others I found online are 1324 B1, B3, C3, D3, E2, E4, I2, J1, J2, J8, K9, L9.

Those suggest to me that we are looking at an MY-format date code where A = Jan and L = Dec, and years range from 1948 to 1954. Thus A0 = Jan 1950.

Nice! Thanks. As I suspected, the single is a real oldie but goodie. Pity I don't have another like that one

 

[Oskari]

Quote:

 
fX1 B8L — Another fX1, and this time it's a 1958 model!
 
Thanks for the lovely photos, guys!
 
Sorry I haven't had the energy to pay much attention to what's inside the glass among all this code gibberish.

 

[dminches]

Well, get to it!
 
I know mine have a D getter.  That's all I paid attention to.

 

[rosgr63]

David you are not showing enough love, that's bad! 

 

[dminches]

Baby steps

 

[rosgr63]

I was worried for a minute!

 

[dminches]