Tung-Sol 5881 - Hard, Medium, Soft?

[Leo_Gnardo]

Is all the talk about EL844's reducing output power just chatter? I had a pair of EL844's but didn't use them as the bias was so far out of whack I promised myself never to touch them again. But now I'm curious to do this experiment!

Since I first heard of 'em EL844 sounded like a scheme to sell lame tubes. Whether they are "engineered" to be lame, or just regular EL84's that don't make the grade, nobody seems to know, you're the only one that's tried 'em yet g-one. (put brave looking smiley thing here.)

FWIW about 20-25 years ago I gave up on EI EL84, same reason. They all ran red hot at "normal" bias voltage settings, and if you set bias to safe plate power levels, the crossover notch was huge. Wonder if JJ just copied these.

[pdf64]

'So are you saying they will just work the same way and over-dissipate which would just bring on red-plating sooner?
I haven't looked at that with any kind of measurement but I think it would depend on the actual circuit. In lower power amps I guess it should not be noticeable?'

Yes, my thinking is that in theory, given that the published curves are the same (the only discrepancy being lower limiting values on the 5881), as long as the circuit operating conditions didn't breach the 5881 limiting values, then the amp should perform the same whether fitted with 5881 or 6L6GC?

How well in practice any individual tube conforms to its spec is another matter!

[Jazz P Bass]

nobody seems to know, you're the only one that's tried 'em yet g-one. (put brave looking smiley thing here.)

[km6xz]

Someone brought some "Tung-Sol" 5881 tubes because he wanted them installed in his amp based on internet experts. I never saw one in the flesh before but looking at the plate I recognized it but could not quite remember what I had seen it in before. I dug a few boxes of Soviet era tubes and sure enough, the tube is identical to a version of 6П3с-е made in the USSR up until about 1980 by one of the plants where were making 6П3 series tube(11 plants were making tubes with the same basic design). So I do know the tube and it is an ordinary $3-5 6П3с-е. But that is not bad, they were all very rugged despite their 250v max anode voltage spec. These are the tubes Groove tube started importing and acid washing the labels off and re-labeled 6L6 to start the whole imported-surplus-$0.35-tube-sold-at-premium-price industry. These new ones that the old Reflektor plant is making are probably just using the old dies for the plates but making new copies which explains why they are selling good, bad, and very bad versions. The surplus originals would have been crushed and recycled if they were low gain. If copies well, they will be fine and will be rugged but not as rugged at the old ones that cost $0.35. Those are running out, still several thousand in various warehouses and barns and still available on eBay but for $5-10. The originals all had wafer bases which added to their strength. Beware that some surplus sales outlets are selling 6П3с as the same as the 6П3с-е. Think of the former as a super 6V6 and the latter as a superior 5881.
Bias? Every tube needs bias adjusted to keep within dissipation limits when running AB1 and hard driven amps often run AB2 so grid dissipation needs to be considered also. Cathode Bias is normally not adjustable unless changing cathode resistor or anode voltage but tweaking makes a difference in type of distortion at which levels. It is only used on lower power applications so exceeding plate dissipation is not as much of a threat to tube life and performance.

It is interesting how Mike Mathews raised prices in Dollars as soon as his cost of manufacturing dropped in 1/2. A tube that cost $2 to make last year now costs $1 and his wholesale price might be $14 now. He can get even more for "brand names" but with the same parts and costs. Apparently some tubes are getting out their factory in purses or manpurses because I just bought some "Mullard" ECC83/12AX7 from a reliable source for 300 rubles($4.50) that are fine but are identical to some Chinese tubes I bought in bulk and labeled with my own brand. They test the same on the curve tracer, have the same plate structure and support frames. I have not been down to Saratov to see their plant but I doubt they would let me in.

[Chuck H]

I have not been down to Saratov to see their plant but I doubt they would let me in.

That's only because they don't know who you are

[Leo_Gnardo]

It is interesting how Mike Mathews raised prices in Dollars as soon as his cost of manufacturing dropped in 1/2. A tube that cost $2 to make last year now costs $1 and his wholesale price might be $14 now. He can get even more for "brand names" but with the same parts and costs.

So the current TungSol 6L6 is just one of those Russian "cheapie" 6Pi3. Yep leave it to good ol' Mikey, he can sell chicken shit as chicken salad, cant' he.

I have a bucket of those 6Pi3, rarely use any. I'm dismayed whenever a customer comes in proclaiming he's just bought the latest greatest tubes, please put em in my amp and bias them, and they turn out to be this dreck. What an insult to a once great name in tube manufacturing. And that goes double, I'm a New Jersey native.

[g1]

Someone brought some "Tung-Sol" 5881 tubes because he wanted them installed in his amp based on internet experts. I never saw one in the flesh before but looking at the plate I recognized it but could not quite remember what I had seen it in before. I dug a few boxes of Soviet era tubes and sure enough, the tube is identical to a version of 6П3с-е made in the USSR up until about 1980 by one of the plants where were making 6П3 series tube(11 plants were making tubes with the same basic design). So I do know the tube and it is an ordinary $3-5 6П3с-е.

Stan, I don't know what you were shown, but I don't think it was what is currently being produced as "tung-sol 5881".
Here is a picture with it on the far right, next to a traditional "sovtek 5881/6П3с-е". As you can see, the bottle is quite a bit smaller and the plate structure is not the same.


Could you have been shown what they are calling a "tung-sol 7581"? (www.thetubestore.com - Tung-Sol 7581 (6L6GC) Audio Tubes)
It would make more sense to me they would try to market the 6П3с-е as being an "upgraded" 6L6 .

[Chuck H]

Nice work Colombo. I had to check for myself after seeing your post because I trust Stan has seen a lot of tubes. Indeed I couldn't find any version of the 6П3, 6П3с or 6П3с-е with a matching plate structure. But it's possible such images are older and REALLY scarce and Stan's memory goes back to a previous geologic era I've noticed before that trying to find images of an older version of something can be impossible when there is a current version and few others in between. So I'm not ready to discount that Stan is looking at a tube just like the new Tung Sol but without the oh so marketable brown base.

[g1]

Well, he did mention "the tubes Groove tube started importing and acid washing the labels off and re-labeled 6L6 to start the whole imported-surplus-$0.35-tube-sold-at-premium-price industry". I saw a lot of those. They were like the sovtek's pictured 2nd from right in the pic. I think when he sees the pic the tung-sols on the far right will not be what he was presented with.

[km6xz]

The "Tung-Sol" tube pair I saw had a brown base but identical plate structure to the 6П3с-е with same square top and bottom mica but with the plate moved up to the top of the smaller glass envelope. Getters at the top almost touching the glass at the top. They looked more like the original 5881's in envelope but the guts of a 6П3с-е. The biased up the same as what he had in his amp. The box looked normal as did the screened ink. Although the same blue prints were used, each of the 11 plants which were making the tube in the day, had little variations probably because they made their on tooling and dies for pressing the plates and stamping the micas. Apparently mixing and matching of plate dies and grid formers is pretty common due to the number of variations in plate structure seen on tubes that are all supposed to be the same, even within a single plant. I doubt any of these plants experiment to perfect any low power glass tubes, that was done 50+ years ago. They have a room full of dies, some 60+ years old, and mix and match until one works for both ease of assembly but also meeting minimum test jig readings. I doubt I have seen any really new forms or materials in decades.

[Audiotexan]

Just wanted to say Great Thread! There's been a lot of great information, and important points covered, that alot of folks might miss, or worse, not realize.

Especially the differences between relabelling (or repurposing in the case of the 6П3с-е), and reissues, and the importance of the differences in specifications (repurposed vs original, reissued vs original).

Also wanted to pop a pic up that might help put things into "laymen's terms" for those that come across this thread in the future about some of the aspects of construction that's being looking at and talked about (and hopefully eliminate confusion for those that might be less-than-certain).


edited pic on left courtesy: g-one
pic on right courtesy: tubemonger.com

[Audiotexan]

The "Tung-Sol" tube pair I saw had a brown base but identical plate structure to the 6П3с-е with same square top and bottom mica but with the plate moved up to the top of the smaller glass envelope. Getters at the top almost touching the glass at the top. They looked more like the original 5881's in envelope but the guts of a 6П3с-е. The biased up the same as what he had in his amp. The box looked normal as did the screened ink. Although the same blue prints were used, each of the 11 plants which were making the tube in the day, had little variations probably because they made their on tooling and dies for pressing the plates and stamping the micas.

I trust your eyes and memory, and if you say that it was "identical plate structure to the 6П3с-е with same square top and bottom mica but with the plate moved up to the top of the smaller glass envelope" I take it to be the truth.

However, I can't really consider "They looked more like the original 5881's in envelope but the guts of a 6П3с-е" a "little variation". If they had the guts of a 6П3с-е, then they are a 6П3с-е. Just with a smaller envelope (glass bottle).

But something about the part of "Although the same blue prints were used, each of the 11 plants which were making the tube in the day" doesn't seem to quite fit for me. Or perhaps I'm misunderstanding something you were trying to say in how you phrased it.

Going as written though, and with my current interpretation, wouldn't there be two sets of blue-prints?? No one I know would call a 5881 a 6L6 when going strictly by blue-prints. Technically speaking (which is all engineers do) they would be strung up by the owner of the factory if they grabbed the wrong blue-prints for a batch order for a customer, and made completely different animals than what was ordered.

(Whether or not they'd still try and sell them is a whole other topic that we all already know the answer to, and a road we've been down.)

[Audiotexan]

Apologies to the OP, et al, for the temp. sidetrack!

Digging back through my personal archived shots, I did find this tube (also relabled/repurposed as 5881/6L6WGC):


But there's obviously no way it could be confused with a 5881. It's still the the same 6П3с-e body, just a revamp (v2?) since they were having complaints/issues from some WRT the clamps/keepers on some amps. I do recall they finally settled on a "normal base" though.


Also curious as to the real (original) designation of the WXT plus (as pictured below) if Stan would be so kind! =)



Perhaps this is the 6П3с?

[Justin Thomas]

Damn, timed out while typing...

There's one way to find out what the TS RIs are. Torture test. I need some bits & pieces. I'll order a pair for my Concert. If they dies, they dies. 510 on the plates, adjustable bias. Let's cook!

Re: same blueprints, different tubes: I've seen 3 different 6L6GCs - GE, RCA, & Sylvania. They all look different, but meet the same specs to be called 6L6GC. I would think this is like the Army - who cares that all the infantrymen look different, so long as they aim and shoot bad guys reluably and consistently? With all those Russian tubes, I doubt the Soviets cared about cosmetic details, so long as each tube from each factory could be plugged in without hassle.

And the Russians never called their tubes 5881 & 6L6GC. That was Aspen & Mikey & followers. Plug em in a Brown Fender - they survive? Call em a 5881. Oh, they survive in a Super Twin? Call em 6L6GC. Hell, plug em in a Ampeg VT22. They survive? Add the extra pins & call em a 7027. Whatever works just so the rebrander can buy em for dimes and sell em for dollars. They even labeled em as 7591s, just re-pinned em. And I don't see any difference, ethically, between this and using the TS name to sell EL34s, KT66s, and KT150s. None of which TS EVER made. Now, 6CA7, 6L6GC, 7027, I'd buy into. But that's a whole different pissing contest!

Justin

[Justin Thomas]

Audiotexan,

I may be wrong, but I consider the oblong-holes tube to be the notorious "indestructible" 5881WXT &/or 5881/6L6WGC, the ones that KG used in his BAGA, or the 7027 subs, the ones that people are still trying to find the limits on. I've heard the difference is in the basing - the wafer base is the former, the other base you pictured is the latter.

The second tube with round holes I think are not as robust. I am inclined to agree with your designation assignments...

Justin