That tube was not made in EI Nis for sure.
The stem is of much lower quality than EI. Different tools were used, not genuine Philips ones.
The cut and form machine (SCHNEID UND BIEGEMÜHLE FUR PRESSTELLER) was set up in a different way.
And finally, Ei never made the ECC81 with short anodes. EI is the only manufacturer that made ECC81 / 12AT7 with long anodes (Telefunken 16.5mm smooth ones) and those tubes from good batches are one of the best sounding ECC81 in many devices.
Looking at some more tiny details, in my opinion it is made in Bangalore, India.
Dragan
tubes.rs
Thanks for the valuable and authoritative information, Dragan. That'll be the first Indian tube in my collection. Another line of thought is the code E74 - could it possibly be a connection to Hyperlec Brive, Correza, Spain (E)?
Regarding EI, I found this quote on an old EI web page:
Another common statement is that EI took over Telefunken tools when Telefunken stopped making tubes in the 70s. Would be interesting to know more about this
Regarding EI, I found this quote on an old EI web page:
"Ei RC operates as a subsidiary of Elektronska Industrija (Ei) Holding Corporation, Niš, Yugoslavia. The factory has been founded in 1951 using Telefunken technology. In 1959 Philips technology had been adapted and production was mainly devoted to the radio and TV tubes."
Another common statement is that EI took over Telefunken tools when Telefunken stopped making tubes in the 70s. Would be interesting to know more about this
E for Espana?!? It's a wonder the smart guys at Philips didn't think of that.
By the way, that's a very accepted opinion, and a lot of people have asked me what I think about Philips Corezza tube quality.
Philips factory codes could be strange sometimes. In this case, there is a very good reason for it.
Philips Brive (aka Hyperlec Brive) is not in Spain, but in France in the town of Brive Al Gaillarde. And it's not Correza, but Corrèze. Philips built a transmitting tubes factory in Brive Al Gaillarde in 1937, right on the bank of Corrèze River. It is interesting that the factory was on Av Maillarde right next to the nightclub Le Cardinal, which still exists and still works today. It was enough to cross Pont Toi bridge and you are already in the city center. The factory was very small, only 25 employees at the beginning, and it only made transmission tubes. Later, production was expanded to klystrons, magnetrons, electron multipliers, dynode multipliers, ...
It was like that until 1960, when Corezze overflowed on 2nd October and flooded almost the entire city. A quarter of the total annual precipitation fell on the city in just 48 hours. The factory was destroyed and it was decided to build a bigger one, at a new location, 5 km far away. It was completed in 1962, and in 1963 it officially became Hyperlec instead of Philips.
A bit of (inevitable) historical facts for the introduction...
What is more important, especially for this forum, is that Philips Brive never made noval double triodes. They had one small line for the production of NOVAL tubes, but they made double tetrodes. What is much more important, they had very specific machines for glass bulbs of great thickness and strength, significantly different from the machines for receiving tubes. Also, the stem machines were unique. It’s not widely known, but Philips raised the production of machines for making electron tubes to an industrial level and produced thousands of them (some of them, such as grid winders)!
These machines were significantly different, very rare and produced in very small series. Stems with a thickness of over 1 cm were easily made.
BEL is another story, very interesting as well.
BHARAT ELECTRONICS LIMITED (BEL), Bangalore, India was established in 1954 as a military factory. They sign a contract with Philips in 1959 on the acquisition of a license for the production of receiving tubes. After that, they buy or, through agreements on mutual cooperation, acquire licenses from many US, EU and Japanese companies for various products and technologies. Among others, from Brown Bowery for transmission tubes. I spoke with a former engineer from BEL who shared some interesting details with me in a phone conversation about 15 years ago. Before the closing of the electronics factory, things went downhill. Everything was running out, and they had to make thier job in nonstandard ways. That's why your Zaerix E81CC is also distorted. Although some parts, such as mica and heater, were manufactured at the highest level until the end. It is possible that some of the grid winders are still left in Bangalore in working condition, they were used to wind coils for speakers in the 21st century. But about that another time. It is important to summarize that all Noval double triodes with E code are made in India.
I'm quite busy and probably a bit lazy. I should travel for a week and in peace in the shade of palm trees 🌴, write a few articles about major European and Soviet tube factories. There really is a lot to be told.
Here are some details about EI Nis Yugoslavia up to 1959 and Telefunken ECC83 / 12AX7 smooth long anode tool controversy.
By the way, that's a very accepted opinion, and a lot of people have asked me what I think about Philips Corezza tube quality.
Philips factory codes could be strange sometimes. In this case, there is a very good reason for it.
Philips Brive (aka Hyperlec Brive) is not in Spain, but in France in the town of Brive Al Gaillarde. And it's not Correza, but Corrèze. Philips built a transmitting tubes factory in Brive Al Gaillarde in 1937, right on the bank of Corrèze River. It is interesting that the factory was on Av Maillarde right next to the nightclub Le Cardinal, which still exists and still works today. It was enough to cross Pont Toi bridge and you are already in the city center. The factory was very small, only 25 employees at the beginning, and it only made transmission tubes. Later, production was expanded to klystrons, magnetrons, electron multipliers, dynode multipliers, ...
It was like that until 1960, when Corezze overflowed on 2nd October and flooded almost the entire city. A quarter of the total annual precipitation fell on the city in just 48 hours. The factory was destroyed and it was decided to build a bigger one, at a new location, 5 km far away. It was completed in 1962, and in 1963 it officially became Hyperlec instead of Philips.
A bit of (inevitable) historical facts for the introduction...
What is more important, especially for this forum, is that Philips Brive never made noval double triodes. They had one small line for the production of NOVAL tubes, but they made double tetrodes. What is much more important, they had very specific machines for glass bulbs of great thickness and strength, significantly different from the machines for receiving tubes. Also, the stem machines were unique. It’s not widely known, but Philips raised the production of machines for making electron tubes to an industrial level and produced thousands of them (some of them, such as grid winders)!
These machines were significantly different, very rare and produced in very small series. Stems with a thickness of over 1 cm were easily made.
BEL is another story, very interesting as well.
BHARAT ELECTRONICS LIMITED (BEL), Bangalore, India was established in 1954 as a military factory. They sign a contract with Philips in 1959 on the acquisition of a license for the production of receiving tubes. After that, they buy or, through agreements on mutual cooperation, acquire licenses from many US, EU and Japanese companies for various products and technologies. Among others, from Brown Bowery for transmission tubes. I spoke with a former engineer from BEL who shared some interesting details with me in a phone conversation about 15 years ago. Before the closing of the electronics factory, things went downhill. Everything was running out, and they had to make thier job in nonstandard ways. That's why your Zaerix E81CC is also distorted. Although some parts, such as mica and heater, were manufactured at the highest level until the end. It is possible that some of the grid winders are still left in Bangalore in working condition, they were used to wind coils for speakers in the 21st century. But about that another time. It is important to summarize that all Noval double triodes with E code are made in India.
I'm quite busy and probably a bit lazy. I should travel for a week and in peace in the shade of palm trees 🌴, write a few articles about major European and Soviet tube factories. There really is a lot to be told.
Here are some details about EI Nis Yugoslavia up to 1959 and Telefunken ECC83 / 12AX7 smooth long anode tool controversy.
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Radiostar: Glad you set the record straight about the Corrèze factory, a lot of web sorces incorrectly place it in Spain. That factory (in France) is identified with "E", just like my Zaerix tube, hence my assumption of its origin. According to the Frank Philipse Philips Factory Valve Codes the code for B.E.L. (Bharat Electronics Ltd) is "V". However, I found another source which - just like you - confirms that the code is "E":
Very much like the Zaerix code. More interesting information about B.E.L. from that very site:
https://www.effectrode.com/news/what-mullard-tubes-india/
So it seems the Zaerix E81CC was manufactured by B.E.L. I had it measured yesterday on an Avo VCM 163 and it performs perfectly well:
IA: 12,5/12 mA
Gm: 6/6 mA/V
Now I very much look forward to Radiostar's "articles about major European and Soviet tube factories".
Very much like the Zaerix code. More interesting information about B.E.L. from that very site:
https://www.effectrode.com/news/what-mullard-tubes-india/
So it seems the Zaerix E81CC was manufactured by B.E.L. I had it measured yesterday on an Avo VCM 163 and it performs perfectly well:
IA: 12,5/12 mA
Gm: 6/6 mA/V
Now I very much look forward to Radiostar's "articles about major European and Soviet tube factories".
