[NCSUZoSo]

correct, it's a tube buffer.

 

[CoiL]

 
6AQ8 GE by Siemens
PCC88 Amperex Orange Globe (with Blackburn codes)
6DJ8 GE USA smokey joe
~~6GM8 Mullard German Made

 
Can you please give etched code for each tube in one post or add factory codes to your tube review?
Telling about prints/labels and where/who made it won`t tell much. It`s all about factory codes.
Tubes with a month or even week difference in production time could sound different because of materials batch/source difference.
 
Thank you for your attention.

 

[spacequeen7]

   
Can you please give etched code for each tube in one post or add factory codes to your tube review?
Telling about prints/labels and where/who made it won`t tell much. It`s all about factory codes.
Tubes with a month or even week difference in production time could sound different because of materials batch/source difference.
 
Thank you for your attention.

was wondering about the codes as well 
P.S. any chance for some links to do the research on our own 

 

[ramaka]

 
NCS..you may just have one or the not designated ones that are the same..I know that side getter code means something...I myself just don't know enough about how to 100% identify..

 
Sent a PM instead.

 

[arcorob]

PM answered
 
 
About the codes - That is easier said than done. 70% of my tubes are very hard to make out a code. what I can tell you is how the plates/getters/etc. look ...for example, none of the ones I recommended have the A frame getters ...and people have found the same tubes from the descriptions.  YES..date codes would help but 1) You would have to translate 2) You would have to find a seller that has the date codes 3) date code can be different but same exact tubes, just different year/month/week
 
I will try to get some close ups this week...

 

[CoiL]

YES..date codes would help but 1) You would have to translate 2) You would have to find a seller that has the date codes 3) date code can be different but same exact tubes, just different year/month/week

1) That`s the point of hunting down those NOS tubes. It`s not hard to translate codes, plenty of information about identifying codes. Without codes you could end up with totally different tube despite construction being same (relabeled, other factory/country made or fake) and that might be totally different from what reviewer recommended. 
 
2) You do not have to find seller who has exact same codes but you can choose one close to it so chances to get same sounding tube would be better.
 
3) Like I already said, despite tubes may look exact same by construction, they can be relabeled by different factory/country or even be fake and you could end up with totally different sounding tube thinking that it`s same as reviewer recommended (thinking it`s the "best" tube you going to have). I have few examples of this case and I also have tubes made short time apart and they sound different.
 
so, without codes you can newer know....

 

[NCSUZoSo]

I'm guessing by the word etched, that these are actually there no matter if the ink is gone completely or not?
 
Can we not like rub graphite or something on the tube to get the etching to show?

 

[lwrs10]

Welcome back Coil....glad to see you back.

And Rob, try a 5BK7A tube. It's my #1 tube right now. Been using it for 2 weeks with no issues. Yes I know that is a 5 volt heater tube, and the Aune is 6.3. It is not running excessively hot or bright. There is a chance it can slightly shorted the filiment life, but not by much. Only talking 1.3 volt difference, and quite a few older tube amps do not supply 6.3 volts exactly.

 

[arcorob]

Yes, welcome back Coil. And you are correct, getting the date codes is optimal. Just not always possible.
 
NW...no, they are painted on and prone to peeling. The embedded codes (silvery looking in the glass) are just the tube type such as 6DJ8 or 6GM8..
 
LWRS...I am DONE with these..lol....that little sucker was eating up my tube budget...I only need 1, have a top 4, the rest I have been selling off and two or 3 I know will wind up in a drawer...LOL

 

[spacequeen7]

...I feel warm and fuzzy inside ...lol..play nice boys 

 

[CoiL]

 
NW...no, they are painted on and prone to peeling. The embedded codes (silvery looking in the glass) are just the tube type such as 6DJ8 or 6GM8..

That`s correct, there aren`t always possible to get any reading out of them due to wearing but no, they are not painted and do not peel off like you say. I don`t really know
exactly how they are "printed" but they seem more like etched and are very strongly "put" onto glass, usually last thing to wear off from tube. I have soaked those codes on vinegar acid, rubbed them with cloth and they don`t come off (not that I actually do this to every tube but at beginning it happened). Of course there are some tubes that have weakly etched codes and some fakes can be found/identified by it. They are usually more like brownish-silver color but yes silver are also found (I have few Siemens). In contrary, I have only few tubes that have very strongly printed logos/text/type on glass but most of them come off very easily when they get moisture/water or even finger residue.
 
And those codes are not just tube type. Code says lot more. Only the fist (upper) 3-letter code says which tube type it is, first two say the tube type and 3rd says the revision. For example, my Amperex 6DJ8 (PQ Orange Shield logo) - there`s very little left from that logo but etched code is ok and it says GAE ⊿2A3. GA = 6DJ8 and E= revision E. But second (lower) symbol/number/letter line is most important - 1st means factory where it`s made, 2nd means year, 3rd means month and 4th means week. So, that Amperex PQ is ⊿ = Heerlen Holland factory, 2 = year 1972, A = month January, 3 = 3rd week. Of course codes won`t tell always everything, you must also be somewhat familiar with tube internal construction, materials, getter type and little details like for example on which side getter is welded onto supporting wire/leg or how tube glass is molded together (2 or 4 lines) etc.
Salvatore has already given great source of information about tube identifying on his collection of links found on first post. But here they are again: 

http://www.head-fi.org/t/549508/schiit-lyr-the-tube-rolling-thread/7725#post_9535339
 
http://www.head-fi.org/t/633006/aune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq/1740#post_9396448
 
http://www.audiotubes.com/mullcode.htm
 
http://www.tube-classics.de/TC/Tubes/Valvo/Phlipscode.htm (this is actually interpreted wrong -  Δ = Philips Copenhagen and ⊿ = Philips Heerlen)
 
http://api.viglink.com/api/click?format=go&jsonp=vglnk_jsonp_139205361590712&key=04fea777994d26cd84e01a5e54f4c01d&loc=http%3A%2F%2Fwww.head-fi.org%2Ft%2F633006%2Faune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq%2F2010%23post_9502294&v=1&libId=c17085ab-60bd-49cc-8479-bf3a8a87a1aa&out=http%3A%2F%2Fwww.triodeel.com%2Fimages%2Fphilipstubecodes.pdf&ref=http%3A%2F%2Fwww.head-fi.org%2Ft%2F633006%2Faune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq&title=Aune%20T1%20USB%20Tube%20DAC%2BAmp%20Discussion%20Thread%20***See%20first%20post%20for%20FAQ***%20-%20Page%20135&txt=Philips%20tube%20codes
 
http://api.viglink.com/api/click?format=go&jsonp=vglnk_jsonp_139205364235914&key=04fea777994d26cd84e01a5e54f4c01d&loc=http%3A%2F%2Fwww.head-fi.org%2Ft%2F633006%2Faune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq%2F2010%23post_9502294&v=1&libId=c17085ab-60bd-49cc-8479-bf3a8a87a1aa&out=http%3A%2F%2Fwww.pauls-roehren.de%2Fdownloads%2FPhilipsCodeListAB.pdf&ref=http%3A%2F%2Fwww.head-fi.org%2Ft%2F633006%2Faune-t1-usb-tube-dac-amp-discussion-thread-see-first-post-for-faq&title=Aune%20T1%20USB%20Tube%20DAC%2BAmp%20Discussion%20Thread%20***See%20first%20post%20for%20FAQ***%20-%20Page%20135&txt=Philips%20factory%20valve%20codes
 
 
So guys, time to do some detective work...

 

[bob439]

Thanks for refreshing the tube identification process CoiL, can someone verify my deduction ...
⊿8D4 - Heerlen, 1968 Apr 4th Week ?

 

[CoiL]

What are first 3 letters or type? And now tube type/build comes into play. According to that you can probably identify if it is 68 or 78. Anyone has idea when Heerlen factory stopped producing tubes? All I know (might be wrong) is that they stopped etching codes in mid/late 70`s.

 

[lwrs10]

Most European tubes after 1957 had the etching until about 1976. You cannot wipe the etching off. Most US tubes were pained on, and it wipes off very easy. The date codes are often very confusing and are not consistant.

Only tubes that are very consistent for factory codes are American octal base tubes.

I will link a website when I get home for help........

But dammit knock the arguing off you two.

 

[NCSUZoSo]

Here is what my tube seller said about my possible CCa:
 

The ones marked cca, re also coded with an A1-9, which means they are all the same 6922 construction. I think they designated the cca as such was because they passed more vigorous testing for specific applications. I don't know if that would be specifically for audio use, because all 6922/e88cc versions were meant to be very low noise, as well as tightly matched triode sections. But I do know that an A9 is an A9 no matter what the printed logo says.

 
 
By A9 he is talking about on the internal shield seen here: