The 6SN7 Identification Guide
Jul 18, 2023 at 12:03 PM Post #496 of 529
According to that pdf, it's both! Further down the page 1945 is marked as V. In the shipping date section.

Tracking the dates of old tubes is fun detective work... especially since most manufacturers didn't want most to know the actual build date vs ship date. In this case, expect the ship date of those tubes was 1945, but the build date was much earlier.

At least we can be thankful they didn't print a gaudy Best Before Date - we'd be screwed. 🤣
🤣 That's so true. Yes, towards the top of that PDF document, the date coding is different. But if one looks a bit more into what those codes are for it doesn't seem that it applies to these tubes. List that @JKDJedi read indicates manufacture date of "metal recemng" tubes, and then the one bellow is for "special-purpose tubes". VT 231 / 6SN7 GT tubes don't belong to either of those categories from little that I know. They're definitely not made in 1975 as per "special-purpose" list for letter "V", since RCA didn't make tubes that look this that late. They have "2 extra rectangular mica pieces attached to either side of round top mica" (visible behind greyed out glass on right side of 2nd image I attached). I used Head-Fi Reference 67SN7 thread to identify them. Based on info from the thread, RCA made grey glass tubes to about 1956. So, I guess it's another little mystery, but based on their look I am inclined to think I got a pair (though separately) that is from Jan-Feb of '45. Even if not, they sound great, so I'll just focus on that. I was just curious. :smile_phones:

 
Jul 18, 2023 at 12:07 PM Post #497 of 529
🤣 That's so true. Yes, towards the top of that PDF document, the date coding is different. But if one looks a bit more into what those codes are for it doesn't seem that it applies to these tubes. List that @JKDJedi read indicates manufacture date of "metal recemng" tubes, and then the one bellow is for "special-purpose tubes". VT 231 / 6SN7 GT tubes don't belong to either of those categories from little that I know. They're definitely not made in 1975 as per "special-purpose" list for letter "V", since RCA didn't make tubes that look this that late. They have "2 extra rectangular mica pieces attached to either side of round top mica" (visible behind greyed out glass on right side of 2nd image I attached). I used Head-Fi Reference 67SN7 thread to identify them. Based on info from the thread, RCA made grey glass tubes to about 1956. So, I guess it's another little mystery, but based on their look I am inclined to think I got a pair (though separately) that is from Jan-Feb of '45. Even if not, they sound great, so I'll just focus on that. I was just curious. :smile_phones:

That and the VT-231 were made early on.. so I couldn't argue against that 1945, we could have gone without the confusing PDF file. I did see a chronological list out there on the net that might help you, just wish I kept the bookmark on that one.
 
Jul 18, 2023 at 1:37 PM Post #498 of 529
Thanks! Yes, I should have asked without referencing that PDF file, but I wasn't sure where to start as I don't know much except what I find here and read on other forums online. One of these came from a pair I got with an amp; it was mismatched with newer '52 RCA without 2 extra micas. I found other one on eBay (one that has type indicated) only by visually looking for RCA with these extra micas wherever photos were bright enough. It was half covered with shellack. It likely sat unused in a gunk for many years until reseller found it. I got lucky with that find as anything before 50's goes for a lot. Excellent tube with sound character true to tubes and not as clinical. It's a keeper; hopefully it'll last for a while.
 
Jul 18, 2023 at 2:07 PM Post #499 of 529
Thanks! Yes, I should have asked without referencing that PDF file, but I wasn't sure where to start as I don't know much except what I find here and read on other forums online. One of these came from a pair I got with an amp; it was mismatched with newer '52 RCA without 2 extra micas. I found other one on eBay (one that has type indicated) only by visually looking for RCA with these extra micas wherever photos were bright enough. It was half covered with shellack. It likely sat unused in a gunk for many years until reseller found it. I got lucky with that find as anything before 50's goes for a lot. Excellent tube with sound character true to tubes and not as clinical. It's a keeper; hopefully it'll last for a while.
Few of the guys here can test that tube for you. And I wouldn't blame ya for being uncomfortable shipping that out but members here would be happy to test that tube.
 
Jul 18, 2023 at 2:41 PM Post #500 of 529
Few of the guys here can test that tube for you. And I wouldn't blame ya for being uncomfortable shipping that out but members here would be happy to test that tube.
I appreciate you suggesting. I should have mentioned though that it was tested by reseller that I got it from on eBay at 100/104 (with min 50) on a calibrated TV-7U. They sell a lot of antique stuff, not only tubes, with over 12k in feedback and 100% positive. That's very hard to get so I trust their testing. It appears to be old NOS spare, but it may be used. I got into this to a point I am considering getting a tube tester just to play with, but I am not sure that's smart.
 
Jul 18, 2023 at 3:19 PM Post #501 of 529
I appreciate you suggesting. I should have mentioned though that it was tested by reseller that I got it from on eBay at 100/104 (with min 50) on a calibrated TV-7U. They sell a lot of antique stuff, not only tubes, with over 12k in feedback and 100% positive. That's very hard to get so I trust their testing. It appears to be old NOS spare, but it may be used. I got into this to a point I am considering getting a tube tester just to play with, but I am not sure that's smart.
Your golden, those are gonna last you a lifetime.
 
Aug 16, 2023 at 7:18 AM Post #502 of 529
Can I get some help to ID this 6F8G? It looks like RCA with the staggered ladder plates and round mica but I’ve never seen one that comes with cooling fins and mica support like that.

IMG_4728.jpeg
 
Dec 7, 2023 at 2:22 PM Post #503 of 529
Dec 7, 2023 at 2:59 PM Post #504 of 529
Made by PSVANE...https://www.aliexpress.com/item/1005004903333380.html
Cant comment on this 6SN7 but I have used their regular 300B, WE300B and ACME 805, and QC are really good. 805 has passed 6000 hours, WE300B has passed 3000 hours and still no drifting.
 
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Jan 13, 2024 at 3:00 AM Post #505 of 529
Can any of you experts confirm if this is an authentic CBS-HYTRON 5692 - it has the rods but doesn't appear to be 5 of them, like with the RCA version. Also, can anyone comment on the test findings/ratings of this tube (assuming it's a legit 5692). It doesn't appear well balanced in my novice opinion, but I have no idea of the book NOS ratings... Has it plenty of life left?

EDIT: seems (i think) it has around 65ish% left on it. Have bought but can return if need be. Will post further pics of better views with the rods...

Any advice would be most appreciated

CBS-HYTRON 5692.png


CBS-HYTRON 5692 2.png


CBS-HYTRON 5692 3.png
 
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Jan 13, 2024 at 10:19 AM Post #506 of 529
It is a CBS 5692 alright but I believe those pictures are from 2 tubes not 1. As you have mentioned, there are 5 rods...1 on 3 sides and 2 on one side between the 2 plates. Below is the datasheet, you can compare it to the tested results. BTW, you can always download the datasheet from here...

The Valve Museum: http://www.r-type.org/
Frank's Electron tube Pages: https://frank.pocnet.net/

Untitled-1.jpg
 
Jan 13, 2024 at 10:25 AM Post #507 of 529
It is a CBS 5692 alright but I believe those pictures are from 2 tubes not 1. As you have mentioned, there are 5 rods...1 on 3 sides and 2 on one side between the 2 plates. Below is the datasheet, you can compare it to the tested results. BTW, you can always download the datasheet from here...

The Valve Museum: http://www.r-type.org/
Frank's Electron tube Pages: https://frank.pocnet.net/

Untitled-1.jpg

Pic is definitely two different tubes.
 

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