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Description
Platinum matched pair ECC83 12AX7 EI Yugoslavia Telefunken Long Smooth Plates 17mm NOS NIB rebranded UnitedTwo (2) fully tested NOS tubes, platinum matched pair of rare ECC83 12AX7 EI made in Yugoslavia on genuine Telefunken made tooling machines, rebranded United National. They are real vintage NOS tubes in original boxes made back in late 80s early 90s in EI tube factory in Nis, Serbia. (Elektronska Industrija Nis) If you like sound of Telefunken's smooth plates ECC83 12AX7, you'll like these too, because they are (almost) exact copy. The only
Two (2) fully tested NOS tubes, platinum matched pair of rare ECC83 12AX7 EI made in Yugoslavia on genuine Telefunken made tooling machines, rebranded United National.
They are real vintage NOS tubes in original boxes made back in late 80s - early 90s in EI tube factory in Nis, Serbia. (Elektronska Industrija Nis)
If you like sound of Telefunken's smooth plates ECC83 12AX7, you'll like these too, because they are (almost) exact copy. The only differences are in thickness of halo getter and in "staples" which are facing each other.
I have few 100 pcs boxes of these tubes and I had enough time last few months to carefully measure them on my Metrix and Tesla tube testers for plate currents and Hickok for transconductance and to make platinum matched pairs with balanced triode sections.
You can find them rebranded Telefunken, Philips and Siemens, because all three factories had contracts with EI. These are pre war tubes, with exceptional quality, made with 1st class materials, because of that many of them have been rebranded like long life premium versions E83CC and sold by Siemens and Philips in their boxes.
You can also find them relabeled Telefunken with diamond mark on the bottom last few years! Diamond bottom mark is done on laser machine, and if you want to avoid that and to be sure that you are buying genuine Telefunken ECC83 12AX7, just take a look at getter and how staples are faced. Diamond bottom is not proof any more ...
If you want to know more about Telefunken ECC83 12AX7 and different types of smooth plate and ribbed plate versions you should read this article on my site: www.tubes.rs/ecc83-telefunken-12ax7/
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4.1 ★★★★★
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Product Reviews
★★★★★ 5
Great Place to Start
Format: Paperback
Clear and entertaining
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Reviewed in the United States on February 17, 2026
★★★★★ 5
Engaging Read for Beginners and Techies Alike
Format: Paperback
An engaging and accessible exploration of how computers really work. The author breaks down complex concepts into simple, relatable explanations, making topics like binary, logic gates, and basic circuits far less intimidating. For newcomers, it’s a great way to build a foundational understanding of computer theory with just a touch of electrical engineering.
As someone with a technical background, I still found it entertaining; the examples and analogies added fresh ways to frame ideas I already knew. It’s the kind of book that can bridge the gap between “I use computers” and “I understand what’s happening under the hood.”
Highly recommended for anyone curious about what makes hardware and software tick, whether you’re starting from scratch or just want a new perspective.
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Reviewed in the United States on August 19, 2025
★★★★★ 5
CODE is the book you should get.
Format: Paperback
The best book to enter the field. Grateful that Charles Petzold decided to write it, even happier this was one of the first books I picked up.
Recommend to everyone wanting to become a programmer, or just interested in computers.
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Reviewed in the United States on January 12, 2026
★★★★★ 5
If you only buy one technical computer book, this is it
Format: Paperback
Disclaimer: I owned the first edition for years and read it a dozen times, mainly for pleasure since it’s not only informative but also just enjoyable to read. I’m a professional software architect and have dozens of textbooks on computer science and engineering so I’ve been around the block.
This is the kind of book I would buy all for all my friends (if I had more than a couple) and family members (if they were even slightly into computers, which they aren’t sadly). Petzold does an exceptional job at describing digital logic and guides you through building a conceptual CPU from very first principles.
I think his bottom up approach is the way to go and has helped me understand complex topics in an extremely simple way. When I’m not reading fiction, this is my go to bedtime reading.
The second edition has about 100 more pages than the first and some content has been completely reworked and it’s great.
If you ever had even a passing interest in knowing how computers work at a very fundamental level, get this book!
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Reviewed in the United States on January 31, 2023
★★★★★ 4
First programmer?
Format: Paperback
As an ardent reader of the past 1st edition, I was fairly excited to get the latest version. That is, until I encountered the history chapter of the new edition.
For one thing, what I do NOT understand in this second edition is the newly added description of August Ada Byron (countless of Lovelace). The author claims it was Babbage who was the first programmer to design the engines, not Ada. I am not trying to start a futile argument here about who has more or fewer contributions, etc.
What I am trying to assert here is that it is undisputed that Ada (unless the new evidence arises) left *the very first demonstration* of what this seemingly imaginary machine, which didn't even physically exist, was capable of through her program. Because Babbage designed the engine itself, that doesn't automatically put him in the position of a programmer (despite Babbage being a brilliant engineer/scientist and may have had a simple or detailed program in his mind). However, it was Ada who gave a definite touch to programming concepts that ultimately led to modern-day programming. Ada deserves more recognition than a mere "tutorial writer," and she is certainly entitled to the title she deserves.
Other than that, like the previous edition, this book is a must-read for people who are from related/unrelated fields. I always loved the 1st edition, and I would do too with the 2nd. Still, I think history should always be approached with more care, particularly if matters have potential controversies.
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Reviewed in the United States on January 6, 2023