EL509-2

This tube is given for the tube "full" AF amplifier V10 and model V10-2 from T+A Elektroakustik in Germany for the output stage. The amplifier has 10 tubes alltogether and a bandwith of 8 Hz to 100 kHz (-3dB). The four output tubes 509... deliver 2 x 110 watt RMS (2 x 80 Music). The manufacturer is stating tubes EL509/2 but in the V10 one can detect the EL509S - the S probably standing for Swetlana.

My question is: is the EL509S a EL509/2 (EL509/II) or does the data varie? In any case should we create the EL509S - at least when data is available.

Dear Ernst,

Some time ago I purchased a couple of EL509S tubes from JJ Electronic, made in Slovak Republic, new in box, at a flee-market.

I was assured that they were really improved EL509, but I was not allowed to open the boxes.

At home it appeared, that these tubes had an octal base and no top-cap.

The datasheet from JJ Electronic I found on the internet, stating the same performance as the (original) EL509.

The pin-out is like the 6L6, but pin 1 (ground) is missing.

Best regards.

Attachments

• datasheet EL509S (121 KB)

Dear Jan
Thank you very much for this answer and the interesting attachment.
It is quite misleading when they write of an EL509 - which always has a top contact - but then show a tube without top contact - most probably an EL509/II ...

I hope somebody will upload this after having cut the top with the name EL509 ... and after creating the tube EL509S. In the notes it would be good to mention the differences in data and apperiance between EL509, EL509S, EL509/2 (EL509/II) and EL509/3 ... I just can't do it timewise ... sorry.

It's likely in reality that the magnoval with top cap PL509 and EL509 are lower Anode capacitance and better performance than octal EL509/II and LE509S without top caps.

The EL509 says 2.5pF Cag₁ with 3pF max and the EL509S just says Cag₁ 3 pF  (no clue if this typical or max). Also that is not the entire Anode to everything else capacitance. The "true" EL509 is indentical to the PL509 except for heater voltage and current (40V vs 6.3V).

It's also likely the Octal version with no top cap has higher inductances in series each electrode. I suppose the Octal EL509/II and EL509S are for Audiophile market where design has exposed tubes for "appearance". The "proper" EL509 with better performance magnoval base and top cap needs to be "inside" a cabinet or cage.

The EL519  or PL519 is the improved version of EL509 / PL509, not the EL509S. In the advert they claim EL509S is 42W plate dissapation but their own data sheet has g₂ = 9W and a + g₂ = 42W, so the "real" Pa Max is 42-9 = 33W.

EL509/PL509 Pa = 30W

EL519/PL519 Pa = 35W, P(a + g₂)= 36W Tolerance Limit P(a + g₂)= 42W,  Pg₂= 7W, Tolerance Limit P g₂= 9W  (datasheet says Toleranzgrenzwert)

It seems more like a an EL519 limited by octal packaging vs Magnoval than an "Improved" EL509 or EL509/II