Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kasperbergholt on April 20, 2024, 09:02:35 am
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Clever people,
About half a year ago, I got a quad of Russian 6N3C-E tubes for my Leben amplifier. They were very reasonably priced in comparison to old stock 5881s for example.
I'm now considering getting af couple of more quads for future use. In that connection, I see a lot of listings of 6N3C tubes at roughly half the price.
Different sources say (somewhat) different things on their nature & compatibility. Some that the 6P3S is an quivalent to the 6L6GC and will replace them directly. Others that the 6P3S-E compatible wth the 6L6GC and the 5881, others that it's only roughly similar to the 6L6G/GA/GB.
Others state that the 6NC3 and the 6N3C-E are the same, but the E version a ruggedized version of the two. However, they seem quite different in structure to me. The 6NC-3 look very much like the modern day 5881/6L6WGC (which the Leben came preinstalled with).
In my Leben 600 (https://bergholt.net/tubes) I can chose either 350V/DC or 410V/DC for plate voltage - and 680 ohms or 460 ohms for the cathode resistors.
Would 6N3C tubes work with either of these settings?
First priority is not to harm the amplifier in any way by using tubes that it's not constructed to work with in the first place.
Thanks in advance,
Kasper
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I've looked through the tube listings at https://frank.pocnet.net/sheets6.html (https://frank.pocnet.net/sheets6.html) and can't find a 63NC.
As far as 6P3S and 6P3S-E goes, my (limited!) understanding is that the E version is "ruggedized" and uses a button style base.
You are correct in pointing out that the getter is often located at the bottom of the tube on the S version, but seems to be always at the top of the S-E version. I'm not aware of other differences, but don't consider myself to be an expert in Russian tubes.
I've used the 6P3S-E version quite a bit in my builds; they are similar to 5881 but I have not yet had one fail on me, knock on wood. I personally can't hear any sonic differences between the 5881's and the 6P3S-E, though YMMV.
I think there is some confusion about the nomenclature of these tubes due to difficulties in translating the Cyrillic alphabet to ours.
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I've looked through the tube listings at https://frank.pocnet.net/sheets6.html (https://frank.pocnet.net/sheets6.html) and can't find a 63NC.
As far as 6P3S and 6P3S-E goes, my (limited!) understanding is that the E version is "ruggedized" and uses a button style base.
You are correct in pointing out that the getter is often located at the bottom of the tube on the S version, but seems to be always at the top of the S-E version. I'm not aware of other differences, but don't consider myself to be an expert in Russian tubes.
I've used the 6P3S-E version quite a bit in my builds; they are similar to 5881 but I have not yet had one fail on me, knock on wood. I personally can't hear any sonic differences between the 5881's and the 6P3S-E, though YMMV.
I think there is some confusion about the nomenclature of these tubes due to difficulties in translating the Cyrillic alphabet to ours.
Thank you for the feedback, it's appreciated :) What types of builds have you used the 6P3S-Es in?
For the nomenclature, my understanding is that 6П3C & 6P3S are the same tube using different characters - Radiomuseum has both designations in one listing (6П3C/6P3S (https://www.radiomuseum.org/tubes/tube_6p3s.html)) - and the same for the (6П3C-E/6P3S-E (https://www.radiomuseum.org/tubes/tube_6p3s-e.html)); but no datasheets for the former. Other shapes are listed as: (e.g. bulb type): 3108_OSW ; 6L6G ; 6L6GA ; 6L6_DDR ; 6Л6С ; 6П3 ; 6П3С-Е ; OSW3108.
A user comments with the following specs for the 6NC3:
"VA=250V, VG2=250V, VG1=-14V, IA=72mA, IG2=5V, S=6mA/V, K(µ)=150, Ri=25000Ω, Ra=2500Ω, Po=5.5W, P=20.5W, Capacité entre G/A=1pF".
It seems the history of development is 6N3 -> 6N3C -> 6N3C-E.
I've got a quad of Es in my Leben 600 now - and they sound very similar to the 5881s it came with from the factory.
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can't find a 63NC
Maybe a bit of confusion. Probably should be looking for 6N3C? Try this...
https://frank.pocnet.net/sheets66.html
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can't find a 63NC
Maybe a bit of confusion. Probably should be looking for 6N3C? Try this...
https://frank.pocnet.net/sheets66.html
It's my bad, sorry - I got the it wrong in both the title of the post & the body text. I've updated where I could. Thanks for the feedback :)
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What types of builds have you used the 6P3S-Es in?
Anywhere a 5881 would be appropriate.
One specialized use is that I have a set of proven tough tubes to use at startup, and the 63PS-E is in that set.
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... my understanding is that 6П3C & 6P3S are the same tube ... (6П3C/6P3S (https://www.radiomuseum.org/tubes/tube_6p3s.html)) - and the same for the (6П3C-E/6P3S-E (https://www.radiomuseum.org/tubes/tube_6p3s-e.html)); but no datasheets for the former. ...
I would continue to use 6P3S-E tubes if you think your amp runs tubes hard, or needs 6L6GCs.
The 6π3C (6P3S) (https://frank.pocnet.net/sheets/084/6/6P3S.pdf) is akin to the metal 6L6s. The linked data sheet puts the max plate dissipation at 20.5 watts, or 22.75 watts for the screen tied to the plate.
(https://tubes-store.com/images/w400/6p3s.jpg)
The 6π3C-E (6P3S-E) (https://frank.pocnet.net/sheets/084/6/6P3S-E.pdf) is a much stouter tube, though its data sheet ratings appear to say the same stuff as the 6P3S. People have been running those at 450+ volts in amps (and dissipating as though they were 6L6GCs) for the last 30-40 years.
(https://www.nostubeshop.com/images/6p3s-e.jpg)
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^What HBP said^. Don't bother with the 6P3S - they're fire-crackers above 250V
6P3S-e is a completely different tube though - different electrode cage and everything (despite the similar nomenclature). Easily runs at 460 B+
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... my understanding is that 6П3C & 6P3S are the same tube ... (6П3C/6P3S (https://www.radiomuseum.org/tubes/tube_6p3s.html)) - and the same for the (6П3C-E/6P3S-E (https://www.radiomuseum.org/tubes/tube_6p3s-e.html)); but no datasheets for the former. ...
I would continue to use 6P3S-E tubes if you think your amp runs tubes hard, or needs 6L6GCs.
The 6π3C (6P3S) (https://frank.pocnet.net/sheets/084/6/6P3S.pdf) is akin to the metal 6L6s. The linked data sheet puts the max plate dissipation at 20.5 watts, or 22.75 watts for the screen tied to the plate.
(https://tubes-store.com/images/w400/6p3s.jpg)
The 6π3C-E (6P3S-E) (https://frank.pocnet.net/sheets/084/6/6P3S-E.pdf) is a much stouter tube, though its data sheet ratings appear to say the same stuff as the 6P3S. People have been running those at 450+ volts in amps (and dissipating as though they were 6L6GCs) for the last 30-40 years.
(https://www.nostubeshop.com/images/6p3s-e.jpg)
Thank you for the explanations, the photos & the recommendation - it was exactly something like this it was looking for when asking the question :)
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^What HBP said^. Don't bother with the 6P3S - they're fire-crackers above 250V
6P3S-e is a completely different tube though - different electrode cage and everything (despite the similar nomenclature). Easily runs at 460 B+
Thank you :)
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From the pages of a russian seller
(https://i.imgur.com/BQd58xk.png)
Franco