An ode to the great giant – EI Nis

The supplied power tubes (of Euterpe Headphone Amplifier) are NOS (new-old stock), branded “EI” and stamped “Yugoslavia”. Always cool to have tubes made in a country that no longer exists!” – Brent Butterworth, Sound Stage Solo


This is a kind of an article which will be of interest to the elder generation of audiophiles whose amplifiers were often adorned with EI tubes in the past. Young music lovers are likely to get up and go to their rack to check if they are the lucky guys who have EI - EL95, PL95, ECC83, EL34... marked “Made in Yugoslavia”. I hope there is also a third group whom this article might encourage to think about having a tube amp at there home.

“Once upon a time” just 100 km away from where this story begins, there was a company which was employing over 10 thousand people, one of the greatest Yugoslavian companies and the most significant electronic industry in this part of Europe – Electronic Industry Nis.





 Products that could be found in the global market, from Europe and Asia, to the North America were including washing machines, medical appliances, auto electronics, x-ray machines, radios, tv’s (which my granny still has at her home and guess what – IT STILL WORKS !)... I don’t know if she just took good care of her “childhood buddy” so it’s still functioning or it’s just the quality of craftsmanship but I doubt that warranty period is “50 years from the date of purchase”.

Back to the topic, in 60’s and 70’s EI was also recognized as one of the few remaining manufacturers of vacuum tubes, all based on Telefunken and Philips technology.

Today, original tubes from this manufacturer are rare to find but you can always check it out in Auris Audio headphone amplifiers – Euterpe and HA-2SE.

In 70’s, it is recorded that after passing by the parking lot which was tight for all employees cars, surprised foreign diplomats went to a meeting with a state representatives and insisted on cooperation, stating: “We weren’t informed that you have such a developed automotive industry, let’s cooperate” :)

Today, that parking is a wild dump.

During the recent years, EI was slowly dying out in silence and growing misery. Cobwebs have been engulfed in rusted machines and destroyed buildings, while tables and chairs which left, remind that before the spiders, humans used to be there.

A real Chernobyl image!



The final nail in the coffin was recorded in 2016, when EI declared bankruptcy after decades of insolvency. Reasons for the factory collapse are various and interpreted differently but that’s some other story.

A light at the end of the tunnel could be Auris Audio, given to our great effort to pass on the former glory of EI, using what is left of them.


The amp stage itself is reasonably sweet to neutral both in terms of timbre and quantity. Coming from the very balanced sounding HA-2SE, I honestly was not surprised to hear another Ei PL95s infused tube amp design deliver another balanced sound.” Marcus, Headfonics



The text above is written in response to many audiophilles questions which we received while exhibiting at the audio shows all over the world and regarding EI. At the same time we want to say thanks to , which we use as a valuable source for this article.