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Russian EL509 / 6KG6 quality question??

Is somebody around here who has bought Russian Svetlana EL509/6KG6 tubes which are offered at ebay quite often??
Sellers are Gintaras (ebay-ID: kwtubes) in Lithuania and Tony Welsh (ebay-ID: tonywelsh) in England .
I`m considering to make a high-power OTL tube amp and therefore would need a hole bunch of them.
Before spending big money I`d like to know about the quality and reliability of this tubes and wether or rather not to buy them? :confused:
BTW: Are this tubes from current production or NOS?

As far I know there is only one other manufacturer of affordable (I don`t want and can`t spend $35/each) EL509`s today, it`s "EI" (Yugoslawia). Any inputs which (and why) to prefer - "EI" or the mentioned "Svetlana"?

Any kind of advice is highly appreciated!!
Thank You!!
 
Thanks Mohan!

Fine to hear about good reliability. Does You refer to current production Svetlana EL509 which is supposed to be even better quality than ever before or to NOS?
I have only 2-4 tubes out of 100 fail on testing.
Does this mean once You had 100 of them?:eek:
I have to admit I`m somewhat curious to know what kind of gear (maybe an OTL tube amp?....or several:) ) You do/did with such an amount of EL509`s?

Is anybody out there who can tell me something about the quality of current production "EI" EL509 also?
 
Christoph,

I specialise in electron tube applications (high power transmitting). My company Australian Electric Valve distributes electron tubes. This will explain my stock of 100+ tubes.

Audio is my hobby. So I design audio amplifiers as well.

I have been stocking Russian tubes since 1990. Tubes that I have in stock are marked in Russian. My comments refer to these. I have not purchased Svetlana branded ones yet. My comments apply to the original Russian production.

I used to have stocks of EI tubes-PL519. These are tonally very pleasing in Tim de Paravicini’s EAR amps. If you use these tubes you may need replacements every two years or so.

More dynamic than the EI tubes are the Tugsram PL519. They are also quite reliable and will last a few more years than EI tubes.

I hope that this answers most of your questions.

Mohan
 
Thanks a bunch Mohan - that`s exactly the information I have hoped to hear!
What You said about the "EI`s" corresponds with rumours I have hard about that they are not the best regarding durability (maybe that`s the reason why they are the cheapest among the EL/PL 509/519). This might be reason enough for me better to invest a little more in higher quality.

Dave and Bernhard:
Thanks to You too. I know Gintaras already from a former purchase (not tubes) and I also think he is very okay. But I thought it cannot harm to hear some other opinions though, unless the one from the seller (the opinion from a seller about the quality of his ware hardly is completely free of bias, even if he otherwise is very honest ;)).
 

Denis

Member
2001-10-13 2:25 pm
cocolino said:
Is somebody around here who has bought Russian Svetlana EL509/6KG6 tubes which are offered at ebay quite often??
Sellers are Gintaras (ebay-ID: kwtubes) in Lithuania and Tony Welsh (ebay-ID: tonywelsh) in England .

These are excellent tubes!

I`m considering to make a high-power OTL tube amp and therefore would need a hole bunch of them.

You need just two pairs of them and two decent OPTs. Do not make an OTL. This is for those who not beleive the blameless transformers do exist. They exist.

Before spending big money I`d like to know about the quality and reliability of this tubes and wether or rather not to buy them? :confused:
BTW: Are this tubes from current production or NOS?

As far as I know, Svetlana EL509 are currently in production.

In good PP pentode output stage EL509 has no rivals.
The best circuit solution is cathode feedback or distributed load circuit like that of QUAD II.
What do you say about a total absence of odd harmonics at low and moderate levels just SET?


Denis.
 
Re: Re: Russian EL509 / 6KG6 quality question??

Denis said:
In good PP pentode output stage EL509 has no rivals.

The best circuit solution is cathode feedback or distributed load circuit like that of QUAD II.
What do you say about a total absence of odd harmonics at low and moderate levels just SET?

Denis.

Denis,

I'm new here but could not help being intrigued by your statement. I recently completed a pair of PP EL509 amps and they sound pretty good. I built them per the schematic in Bruce Rozenblit's Audio Reality book. Since I have been working with these tubes recently your post caught my eye.

Do you have a design such as you mentioned above? I would love to learn more as I don't yet have the knowledge to design an amp from scratch.

Mike
 

Denis

Member
2001-10-13 2:25 pm
Re: Re: Re: Russian EL509 / 6KG6 quality question??

mike galusha said:


Denis,

I'm new here but could not help being intrigued by your statement. I recently completed a pair of PP EL509 amps and they sound pretty good. I built them per the schematic in Bruce Rozenblit's Audio Reality book. Since I have been working with these tubes recently your post caught my eye.

Do you have a design such as you mentioned above? I would love to learn more as I don't yet have the knowledge to design an amp from scratch.

Mike

You can find more on my designs at http://www.cortmi.com.ua/omak
Also I make the special output transformers.
I use one(OMAK J1) or two(OMAK J3) pairs of EL509 tubes in a push-pull arrangement with a cathode feedback. This means a small part of the primary winding (12.5% in my design) is connected to the cathodes of the power tubes providing a local voltage NFB. This arrangement allows one to greatly reduce the output resistance (even better than with triode connection) and get very linear operation over a wide range of loads. The screen grids are connected to a constant B+ supply, and it is esssential that Eg2 < Ep. The proper choice of Eg2 results in almost total elimination of third harmonic from the distortion spectra al low and moderate signal levels. The only significant distortion product is a residual 2H, which depends on tube matching. In this mode of operation the pentodes surpass everything including SET.
The greatest benefit of EL509 over all other power pentodes is that there is a lot of output power even at the above conditions with reduced Eg2 thanks to its enormous emission current.
I use EL509 in class A for the most of load range.
Although one PP pair of EL509s can reliably deliver up to 150W, I use them in far more conservative margins, and the distortion certainly fall below the perception limit.

Best regards.

Denis.
 
I got maybe one in eight failures in a batch of 120 or so I tested and sorted. I forget the exact numbers but it was getting higher than I really wanted... Those were mostly from tubeman.com. A bunch just cracked in the base for no good reason.

The Svetlana tubes come from the same factory as the other Russian ones. ie they're the same although I suppose its possible that Svetlana select theirs. Personally, in hindsight I would say if you want to build an OTL use something cheaper like 6C19s (and hey, you can get those from Gintaras too!) and get more efficient speakers... :)

HTH,

JohnR
 

GUNFU

Banned
2017-03-04 11:12 am
Hello.
One of my clients is preparing a monoblock project on analog EL509 manufactured in Russia at the Svetlana plant.
4547_2.jpg
Unlike European, grids manufactured in Russia have not been twisted as usual, but unique frame grids and still covered with gold. He also managed to select the characteristics of 200 pieces from a very large batch. He wants to make monoblocks with 4 lamps at the output and with a kenotron power supply on the powerful Russian kenotrons 5Ц8С(5С8S in Latin transcription). All transformers, both output and power, will be toroidal and made of nanocrystalline core. The secondary winding of the output transformer with an intermediate point and, in addition to the load, lamp cathodes for local feedback will also be connected to it. A similar solution is used in Audio Research VT-130 amplifiers. The bias stabilization is also similar with some improvements. My personal opinion is better to give up kenotron nutrition in favor of two additional lamps. Since I think the quality gain will be more noticeable from 6 tubes and power from the diode bridge than from 4 tubes and power from the 2 kenotrons. The consumption of electricity, weight, and heat generation will be approximately the same.
 
6P45S is up-rated and ruggedized version of EL509. As mentioned, it has control grid of frame construction, which is gold-brazed and plated with platinum. It has bigger glass envelope to improve cooling. Due to frame grid, these tubes have less scatter of characteristics than EL509s.

Russian tubes were not all made at the same factory. St. Petersburg's Svetlana and Moscow's MELZ were quality leaders in tubes.
 

GUNFU

Banned
2017-03-04 11:12 am
I hasten to apologize. In the 6P42S tubes, the glass size is the same as that of the 6P45S, and the anode power according to datasheet is supposedly the same 35W, but the photo shows the anode size much smaller than 6P45S see in the above links. The grids is also a unique frame, but the tubes no longer spread to TVs because of poor reputation and eventually was replaced by a more powerful 6P45S. The anode power of the 6P45S in the specification is also 35W, but at the same time it for a long time can withstand all 40W unless other modes are exceeded. And I also saw fresh pictures that the 6P42S also had versions with the same anodes as the 6P45S, apparently it depends on different years of production and plants. But the photo on the link above shows that the small anode of the 6P42S in the pipes of the release until 1972 is unambiguous.
In the general case, the grid of frame construction were in 6P45S, 6P42S and 6P41S. The first and the last have a very good reputation for reliability, and the sound is also very good. But the power of the anode 6P41S is only 14 watts in the passport, although it is clearly done with a margin and the size of the glass and anode. 6P41S I listened to many times, and their sound is more neutral than the EL84 and 6L6. When buying 6P42S, you need to see what kind of concrete design the anode has. Naturally, you need to purchase the design of the anode only such as in 6P45S. http://http://radiowiki.ru/index.php?title=%D0%A4%D0%B0%D0%B9%D0%BB:%D0%A0%D0%B0%D0%B4%D0%B8%D0%BE_1968_%D0%B3._%E2%84%9609.djvu&page=62
 

GUNFU

Banned
2017-03-04 11:12 am
Are they relabelled 6П42С?
6П45С the pinout is exactly the same with the EL509 on current-voltage characteristics are not the same. New released after 1972 6П42С characteristics very similar to EL509, the pinout is not. In General 6П42С can not be labeled as EL509 because of the different pinout, even if it is more like the rest. I think it's possible to obtain due to the copying characteristics of the TV tubes in 60-70 years, and protection from prosecution. But it seems that both the new Russian tubes is good in sound, and 6П42С has more convenient pinout because it is not necessary to submit additionally in beam plate is +50V.
http://tec.org.ru/_bd/17/1737_642.pdf
http://www.goldenmiddle.com/files/EL509.pdf
EL 509, Tube EL509; Röhre EL 509 ID18745, Beam Power Tube