EL34 Siemens, Quad, excellent matched ! NOS/NIB ! V221 /222 /217 /223

Description

 Platinum matched Quad Siemens EL34 tubes produced by EI (Elektrinski Industrijia) in Nis, Yugoslavia.

Detailed description

This EL34, new in original boxes, is the only genuine EI version of EL34 from the former Philips factory; Elektrinski Industrijia in Nis, Yugoslavia. The tube is easily identified by the tip on top of the tube (see pictures). The tubes have a disc getter and welded plates. These tubes tend to have a variation in their properties. This quad is a carefull selection from a larger batch. Therefore the quad is matched very well.All four tubes are new and from the same production series and have code 5D3 EI factory code 9F  and O89; assumed june 1989. The factory code is a Philips tube code: a horse shoe above a dot.

These tubes deliver superior sonics. I refer to the many reviews on the web.The quad has NOS test values and good looks. 

Citation: This is killer EL34 to any new production like JJ, Electro-Harmonix, Genalex-Gold Lion, Svetlana, Mullard, Shuguang, Tung-Sol, … EL34 6CA7 KT77. They have been made in 90s, when EI factory has still been a respectable tube manufacturer, with tenths of thousands tubes on monthly basis with strict quality control, tubes were printed depending on order, for many world famous tube brands like Siemens, Philips, Telefunken, RCA, Marshal, Jadis, Valvo, RTC, …

Note: my tubes are often not the cheapest. But is very hard to find better tubes !

Interesting info about the EI factory: https://www.jacmusic.com/techcorner/ARTICLES/English/EI-FACTORY/EI-index.html

Test results

I have a number of these tubes with the same date codes and I have are carefully selected a few tested and matched (by plate current) quads. The measurement data below show that the tubes are matched extremely well. 

Valve  V211

Ia (plate current): Transconductance (Gm): Gas test, Shorts test:

107  mA 12,9  mA/V OK

NOS NOS

Valve  V212

Ia (plate current): Transconductance (Gm): Gas test, Shorts test:

106  mA 12,8  mA/V OK

NOS NOS

Valve  V217

Ia (plate current): Transconductance (Gm): Gas test, Shorts test:

108  mA 12,9  mA/V OK

NOS NOS

Valve  V223

Ia (plate current): Transconductance (Gm): Gas test, Shorts test:

112  mA 13,0  mA/V OK

NOS NOS

Telefunken measuring values for new unused tubes:

• The rated emission value for a new EL34 is:  100 mA. 
• The rated transconductance value for a new EL34 is:  11 mA/V . 

For Telefunken specs info see last picture 

Test conditions & equipment:

Mutual transconductance, plate current, gas and shorts test equipment: AVO Mk IV (Dutch army tester) , AVO Valve Data Manual 23rd edition 1981, RFT stabilised mains, Utracer3+, Philips PE 4832, 2x Korad KA3005P programmable power supply, 2x Keithley 2700 and 2x Fluke 145. 

Test conditions: Ua (plate voltage) = 250 Volts, Us (screen voltage) = 265 Volts, Ug = -13,5 Volts and Uf = 6,3 V ± 3% (factory conditions). Please read our test page.

Summarized description