[adrianc]

SEP.1951 . philips disc getter welded plates ecc81

I like to try them on my Preamp.

[rodama]

Again not my pics but it deserves to be shared

Copenhagen january 1951 ecc81

[shoot]

Again not my pics but it deserves to be shared

Copenhagen january 1951 ecc81

those code maybe printed wrong.because its inside stracture shows it maybe produced in 1953 or 1954

[shoot]

Very old Brimar 12ax7 Black plate 

a little bit later version the astonish thing is this pair have 0 Microphoney

[adrianc]

 

[adrianc]

NOS Brimar 12ax7 never been open 

[mlee]

Quote from: rodama on Yesterday at 02:42 pm

    I hope someday one of those man could iluminate all of us about hundred questions, a lot of tube wisdom and knoweledge will dissapear

I afraid it already happen at least with the 300B. WE already dont know how to made a 300B sound good as in the past.

I suspect there are various details in the making of the 300B that arent in the manuals of the factory.
These important details were known only by the technicians who worked with this valve.
So 300B lovers should forget this tube, the new 300Bs never will sound as the the Vintage 300B.

even WE themselfs couldn't copy their own earlly 300B,so forget it.

Factory engineer cannot give answers, except :

Not only are the materials and design of the tube different from modern materials and design, but the production machinery that make the tubes are themselves old and out-of-spec. 
Modern tube engineers (hah, do they exist ? more like tube lovers trying to reproduce antique tubes) can try to purchase and refurbish the antique machinery, but where do they get the parts ?  No longer made, there is no huge demand like in the 1950s, so they have to use modern makeshift parts and materials.  No design blueprints for the old machinery or how to make the individual parts for the machinery means they are all shooting in the dark.

But I respect them for what they are trying to do.

Cannot afford the tubes you guys own, and I am truly jealous, so I have to settle with the Amperex 7316 D getter (for 12au7):








wow, so delta A TkC and TkB can not only refer to date code or plant code, but getter variation as well ?
again wow, the large tube demand in those days means making specific tubes for everyone. Am I mistaken ?

[shoot]

very nice ecc82

[rodama]

Factory engineer cannot give answers, except :

Not only are the materials and design of the tube different from modern materials and design, but the production machinery that make the tubes are themselves old and out-of-spec. 
Modern tube engineers (hah, do they exist ? more like tube lovers trying to reproduce antique tubes) can try to purchase and refurbish the antique machinery, but where do they get the parts ?  No longer made, there is no huge demand like in the 1950s, so they have to use modern makeshift parts and materials.  No design blueprints for the old machinery or how to make the individual parts for the machinery means they are all shooting in the dark.

But I respect them for what they are trying to do.

Hello mlee, agreed with all you explain, are you a engineer of those golden days?

There are some tube makers that are doing things pretty well even with several restrictions as you said without depured machinery, and most important of all: without mass demand that cover the costs generated in research and development.
Also other factor is the fact that today environmental laws prevent the use of elements that can make tubes sound better but are dangerous for health.

[rodama]

with Mullar characters on glass side.... what are your opinion? 51 or later? maybe between all of us can put light in this case

[rodama]

with Mullard characters on glass side.... what are your opinion? 51 or later? maybe between all of us can put light in this case

[shoot]

with Mullar characters on glass side.... what are your opinion? 51 or later? maybe between all of us can put light in this case

I'd rather judge it with inside stracture than the code.2 bars 1 hole,a little wide D getter,exactly same with my TKP ΔF code ecc81.so I think it's made in about 1954 

[rodama]

I'd rather judge it with inside stracture than the code.2 bars 1 hole,a little wide D getter,exactly same with my TKP ΔF code ecc81.so I think it's made in about 1954 

Ok, you can compare both in hand, so let's take your guess as correct one  ... so the operator had bad day back then when marked these tubes..

[adrianc]

Most valves have a length for a production period,these two valves are 100% identical but with different Date code on the glass and ( Specially ).DIFFERENT YEAR.So just looking at one valve and judge their production year is not accurate,
The TK1 B6B at the right ( 1956 ) Version was made at 1955 ( their is a B5B version ) but the 1552 G4 was made in 1954,so if you only have the B6B version then you will judge this type was made in 1956,for me I will say they were made between one year.

[adrianc]

Ok, you can compare both in hand, so let's take your guess as correct one  ... so the operator had bad day back then when marked these tubes..

Phillips have so many production plants all over the world and the same type of valves made during the same period are likely the same but with different factory code. 

[rodama]

Phillips have so many production plants all over the world and the same type of valves made during the same period are likely the same but with different factory code.

Maybe here a good example of this, what would you say is this ecc82?

[rodama]

nobody?

[adrianc]

nobody?

Amperex Holland 1955-56 ?

[shoot]

have no idea.

[adrianc]

It doesn't looks like a Siemens ?