Russian tube identification

[Zephedone]

I've got 4 of them . Only markings are 8804 and 6n3C . The "n" is more like a lower case n but upper case size . Not sure it is an n at all . Are they a good replacement for 6550s or 6l6gc . Seem to think that I bought them for my 61 blonde bassman .

[RTG]

Hi, the "C" in Cyrillic is usually an "S" in the Latin script.
Not sure about the "n".

[kleuck]

They are 6P3S, similar to 6L6.

http://www.audiotriodes.com/data/6p3c/data.htm

[dotfret]

{edit - got the 6550 and the 5881 crossed up in my mind - and see Zaphod's post below}

It depends where they were made, and what style they are.

Pedants please forgive my memory if I quote a slightly dodgy number, the sentiment of my statements should be accurate.

Standard 6L6 have a plate dissipation of around 12W.

The "official" plate dissipation of any 6P3S (around 15W) is a little higher than most 6L6, so they can substitute for 6L6 in all circumstances.

Two design styles were used. The Svetlana plant in Leningrad (St Petersburg) used a US style design (looks like a standard 6L6 internally) and there is an all Russian design which does not resemble any Western type.

A lot of the Svetlana valves can be substituted for 5881 (18W plate dissipation). Some of the Russian design valves can be substituted for 6L6GC (22W plate dissipation).

Without a test rig, there is really no practical way of knowing which valves can "do the extra mile" other than fitting them and watching out to see if they redplate - then switching off quick if they do!

Russian valves had to be made to the official specifications, which were immutable. But improved designs existed - and each factory had its own idea of what was wanted when a particular valve was requested. A lot of the time, they supplied to a higher spec than was ordered, but minimised the testing if it was a low spec order.

Nobody has said - that "n" is what you would know as the Greek letter "pi", used as P in Cyrillic. 8804 is the date code for April 1988

[DeanM]

i can type russian on my laptop! the "n" would look like "П"

6П3С - 6p3s

[breakfastbuddy]

i thought el 84 is 12w 6l6 is 20w and 6l6gc is 30w and el 34 is 25w .

[zaphod_phil]

Pedants please forgive my memory if I quote a slightly dodgy number, the sentiment of my statements should be accurate. Standard 6L6 have a plate dissipation of around 12W. The "official" plate dissipation of any 6P3S (around 15W) is a little higher than most 6L6, so they can substitute for 6L6 in all circumstances. A lot of the Svetlana valves can be substituted for 6550 (18W plate dissipation). Some of the Russian design valves can be substituted for 6L6GC (22W plate dissipation).

Once again I'm amazed at the "inside information" you come up with! FYI the original 6L6 and 6L6G's dissipation limit was 19W. The 5881 (mil-spec 6L6GB) was 23W, and the 6L6GC 30W. The 6550 has a max dissipation rating of 40W, while it's near equivalent the KT88 is rated at 42W.

The 6pi3c is also commonly marketed as the "Sovtek 5881", which therefore isn't a true 5881. Here is some information I've gleaned in the past about this valve.

A friend of mine near NYC has tested these with a high-voltage supply and found that they will dissipate almost 42W before the plates start to glow. I've tested them as high as 40W (approx. 500V @ 80mA) for red plate conditions in a darkened room (when you can see even the smallest trace of red glow.....). Definately not a regular 6L6GC. It can handle rather high voltages (I've heard rumors of 600VDC not being a problem as long as idle current keeps disspation below specs...). The 5881 nomenclature for this tube is really misleading, as they perform like a slightly-higher-transconductance version of a 7581A or 7027A.... Very hard to kill. I've been using a quartet at 500VDC (with a healthy 45mA of idle current) in a musical instrument amp for at least a year with no signs of weakening. No emmision burn on the glass (even when viewed in front of a clean, white sheet of paper), no rattles, no bad sounds. They've been pumping out 35W/channel all this time...They seem to require a few volts less bias than a 6L6/7027--typically needing -44V to -48V where Fender amps state -48V to -52V on their schemo--and so, sound cold/overbiased and kinda nasty when you don't adjust them for a specific quiescent current.

So they appear to be safe for operation at around 30W to 35W, which puts them somewhere between 6L6GCs and 6550s. I've never heard of anyone using these in an 18W style amp, although a few people have been known to use 6L6s.

[kleuck]

EL34 are 27,5 watts dissipation tubes, and can be used to build amp with a power up to...100 Watts with a single push-pull, class B and 800 volts B+
According to the old datasheets.

[dotfret]

Once again I'm amazed at the "inside information" you come up with!

Yeah, you ARE right, Phil - at least you are so used to my brainstorms, when I confused the 5881 and 6550 it didn't phase you! - but just you wait until your memory is on the way out and you can't get things straight in your head - you'll see how easy it is to talk $ht!

So what I should have said was -
There are these three types, 6L6, 5881, and 6L6GC, in ascending power handling capacity.

There are two basic Russian designs of 6p3s, one of which is like a 6L6 internally, and the other is an original Russian design.

It is possible to use a 6p3s of either design in any place that was designed for a 6L6, and they will usually work in place of a 5881.

Some of the Russian designed 6p3s will work in place of 6L6GC, but not all of them - you have to check them out, if they don't redplate they're fine - but when they do work they often give a cleaner sound, and less hum.

Here's a pic of a 6p3s-e that is OK in place of a 6L6GC - made by Reflector, Saratov, Oct 76 with the OTK diamond mark which designates it good for military use. The "e" suffix should mean "ruggedised envelope construction" and nothing else, but sometimes it might mean more (they could not change the specs once they were written down).



I'm using these with no problems, replacing 6L6GC.