I had a conversation with a tube "expert" last night...

[gui_tarzan]

So the guy that started the FB thread was asking for tube recommendations for a Peavey Classic 50. Someone responded with "EH" and a guy I'll call "Bob" replied "russian tubes suck".

I asked "Bob" why he said that? He went on a tirade about how the 5881 was not an audio tube and had been relabeled by some tube vendors yada yada yada. It went on for a while and he kept using more and more fifty and hundred dollar words (you old timers will understand that expression) to justify his statement and I finally told him he was obviously much smarter than any of the rest of us including the amp designers of the early and mid 1960s and bowed out of the discussion. He even had the balls to say he never said Russian tubes were junk, to which I obviously replied with his original response.

So what if the 5881 isn't the same as a 6L6GC? So what if it's not a true Pentode, it's still a beam transmitter (which I asked if he knew about the original 6L6 being used as a radio transmitter, that's when things got really interesting) and works just fine for certain amp applications.

I ended up blocking him after looking at his FB page, sometimes you just can't argue common sense with people like that. What a waste of a half hour of my time.

[nickb]

These sort of folk have a knack of being vaporized by their own rhetoric

I must have about 60 of those (apparently nasty) Russian 5881's lying around. I clearly need help. They look exactly like 6L6GCs, just a little shorter.

[Justin Thomas]

Do you mean the Tung-Sol RI 5881, or the Sovtek 5881WXT? The latter are quite indestructible, I hear...

Justin

[nickb]

Do you mean the Tung-Sol RI 5881, or the Sovtek 5881WXT? The latter are quite indestructible, I hear...

Justin

Reflector, now Sovtek, I think. Half of them are (latin) 6P3S and the other are 5881WXT. But they are identical, aside from the markings as far as I can tell. I have used then up to 470V without any problems.

[Mick Bailey]

That guy should be telling Fender, Marshall, Engl, Bogner, Soldano, Mesa and quite a few others that they don't know anything about amps or tone. They must all be dumb not realizing Russian 5881 tubes are crap.

If only they were cheap, reliable, rugged, stable, consistent and able to sustain punishing plate and screen voltages that would kill lesser tubes.....

[The Dude]

Confucius say, "He who thinks he knows everything is a dumbass.".

[danfrank]

When Tung-Sol made the 5881 back in the 1950s, they made it for audio. Same with the 6550, which they made also. Some people think that tubes with a 4 number designation are made expressly for the military or industrial applications, which is not correct. These 2 tubes were originally made for audio, even though people have used them for other things, like transmitter tubes.
The New Sensor 5881 (I can't remember the Russian designation) was originally a military tube that Mike Matthews started importing into the USA and marketed it as an audio tube. It works well as an audio output.

[Leo_Gnardo]

New Sensor 5881 (I can't remember the Russian designation) was originally a military tube that Mike Matthews started importing into the USA and marketed it as an audio tube. It works well as an audio output.

You bet, the wafer base "Sovtek 5881" was a bargain and a hit when they first showed up around 1990. I bought 'em tested & matched from Ruby $4 each back then, later I found Mike Matthews was getting 'em by the truckload at 4 for a dollar. Well that's what happens when the gummint collapses & russians sold off anything they could so they could buy a sausage. Been a lot of water under the bridge since then and guess what, they're still a good tube, just cost more. Doesn't everything. Except gas, don't worry that's just temporary, enjoy it while you can.

AFAIK 7591 and 8417 were developed for audio, no mil use. There's some charm to 7591, some Scott hi fi used 'em & old Ampeg combo amps from the 60's.

[potatofarmer]

The Russian tube sold as the "5881 WXT" or "5881/6L6 WGC" is the 6P3S-E. Very important, that -E; the 6P3S is closer to a 6L6GB and if I remember right was sold as a 6V6 equivalent in the early 90s. I have seen some labeled as "6L6" though - I think the quad I found was labeled/sold by National Electronics. Biased cool they seemed to hold up fine in a Fender. Probably less output but with a quad of them that winds up somewhere between "how can you tell?" and "who cares?"

I do love 7591s; a beam tetrode with transconductance like an EL84 but rated for 450V on the screen and a 19W plate. "She's built like a steakhouse, but handles like a bistro."


But "designed for audio" - apart from using microphonic tubes at the input, but that will just cause you to go through dozens trying to find a good one - what design parameters would a tube engineer tweak to make a tube better or worse for audio? I can understand designing for an application, like a small-signal pentode to reduce tube count in a portable radio or altering heater requirements or what have you, but beyond that I don't get it.

[nickb]

The Russian tube sold as the "5881 WXT" or "5881/6L6 WGC" is the 6P3S-E. Very important, that -E; the 6P3S is closer to a 6L6GB and if I remember right was sold as a 6V6 equivalent in the early 90s. I have seen some labeled as "6L6" though - I think the quad I found was labeled/sold by National Electronics. Biased cool they seemed to hold up fine in a Fender. Probably less output but with a quad of them that winds up somewhere between "how can you tell?" and "who cares?"

I do love 7591s; a beam tetrode with transconductance like an EL84 but rated for 450V on the screen and a 19W plate. "She's built like a steakhouse, but handles like a bistro."


But "designed for audio" - apart from using microphonic tubes at the input, but that will just cause you to go through dozens trying to find a good one - what design parameters would a tube engineer tweak to make a tube better or worse for audio? I can understand designing for an application, like a small-signal pentode to reduce tube count in a portable radio or altering heater requirements or what have you, but beyond that I don't get it.

It is the "-E" I have. I don't know how the non-mil version compares since I've never had any. But, I wouldn't be at all surprised to learn that they are mechanically identical with the difference being (a) tighter QA and (b) reduced ratings to ensure longer service life. I had an Engl rack mount head ( 2 x 50W, 450V on the plates) in here recently. It used two pairs of them.

[R.G.]

You can take a horse to water but you can't make him ... think.

Or the more risque version:
You take a whore to Vassar but you can't make her think.

[Enzo]

Or this:

You can lead a horse to drink, but you can't make him water.

[g1]

Very important, that -E; the 6P3S is closer to a 6L6GB and if I remember right was sold as a 6V6 equivalent in the early 90s. I have seen some labeled as "6L6" though - I think the quad I found was labeled/sold by National Electronics. Biased cool they seemed to hold up fine in a Fender.

It is the "-E" I have. I don't know how the non-mil version compares since I've never had any. But, I wouldn't be at all surprised to learn that they are mechanically identical with the difference being (a) tighter QA and (b) reduced ratings to ensure longer service life. I had an Engl rack mount head ( 2 x 50W, 450V on the plates) in here recently. It used two pairs of them they used.

The non-E didn't look like the -E ("5881"WXT), the bottle was narrower than the base, and it had a rounded rather than flat top. I remember the ones branded "National" and the generic russian ones. In my experience, they didn't hold up as well to high voltage, and were short lived compared to the -E. They red-plated very easily. Maybe would be fine in a circuit designed for original lower voltage/power real 5881.

[rjb]

Or the more risque version:
You take a whore to Vassar but you can't make her think.

The quote attributed to Dorothy Parker is:
"You can lead a horticulture but you can't make her think."
You can lead a horticulture but you can't make her think - meaning and origin.

[Leo_Gnardo]

The non-E didn't look like the -E ("5881"WXT), the bottle was narrower than the base, and it had a rounded rather than flat top. I remember the ones branded "National" and the generic russian ones.

Same here & I still have some around, new and used/good. Another "tell" is the electrodes are all lined up at the bottom and pass thru a rectangular wedge of glass. There's also China made versions, look much the same. True they don't generally hold up to hi voltage & hi plate power but some manage to survive anyway. Similar in single ended, some work fine in a Champ or similar tho it's probably best to increase the cathode R if you want them to survive. Haven't heard any sonic problems in them to complain about.

Yes there was that "Super 6V6" campaign by Groove late 80's - early 90's. Lots of my customers bought into that and were annoyed when their "super" tubes went super red. In recent times we really do have a super 6V6, the JJ. Like 'em a lot.