Sovtek 5881 One Tough Tube

[talbany]

I had the Music Man amp out last night cooking in the corner while checking out a Loop and noticed a funny smell..Went to check on the amp and noticed all 4 tubes were red plating.. Shut the amp down threw it on the bench and found a crippled bias pot.. Popped in another and for the heck of it put the Sovtek's back in to see how badly they cooked.. To my surprise they were all still closely matched within 3 ma.. This is even after 1 years use 700v and bounced around in the back of a semi all over the place 6 months and red plating for who knows how long I biased it up 24ma and still as it was.. I'll probably change them out anyway as it is time and don't want to take a chance but dang that's one tough tube.. If reliability and durability is a high priority take a look at these.. They only sound good in certain amps but built like a farriggin tank..

Hope this helps!!

Tony

[butwhatif]

I like the tungsol 5881, and have not had any issues w/them. the sovtek 5881 i have seen arc out when getting old---

[Structo]

Yeah, I'm kind of surprised stuff like that doesn't happen more often.
What we need is a little window or perhaps an LED circuit that tells us when the power tubes are redplating.

I have a pair of Sovtek 5881 WXT's that were given to me.
I went as far as trying them in my D'lite but wasn't impressed with the tone.
So I have kept them for backup.
Not sure when they were made.
One has Fender on it in gold ink.
They both say Made in Russia.
At the bottom there is a 4 digit code, 00 10.
I think the other one says 03 03.

Good to know they are a stout tube.

Did you put a safety resistor on your bias pot this time?

[talbany]

I like the tungsol 5881, and have not had any issues w/them. the sovtek 5881 i have seen arc out when getting old---

I don't know why Sovtek labeled these 5881's as they are definitely more 6L6 and don't even resemble an 5881..
We've loaded quite a few Fralin amps w/ Tung Sols smooth tube indeed.. a friend of mine gave me a box of these re-branded Stek groove tube 81's and since they handled the 700v gave them a try and figured I would be lucky to get 6 months out of them.. No sparks yet.. I am sure other peoples experiences with these tubes very.. So far I am impressed with toughness and thought I would share..

Tom
Yeah I've tried these in other amps and it's hit or miss.. They sound pretty good in the MM and figured I'd try the Tung Sol 6L's next .. I'll let you know what I find.. Kinda limited on 6L's with the MM..
First time I had a bias pot go south.. It was a 10 turn made in china.. Doh!!.. Safety resistor on the alpha..

[txbluesboy]

The Sovtek 5881 is my favorite 6L6 type tube.

[Steven_nl]

I used Sovteks 5881 as well. Liked the tone, but one gave up after a few months. Didn't use the amp for gigs very often so it suprised me a bit actually.

Steven

[groovtubin]

I like the tungsol 5881, and have not had any issues w/them. the sovtek 5881 i have seen arc out when getting old---

AMEN BRO! Thats ONE great tube! Sick mids!

[67plexi]

I’m paranoid of the new cts 10k bais pots I just had a new one tested good on the bench but after voltage was applied it was toast took the cover off and found carbon dust thick looks like it was the master of sparks inside. Since that I replaced with clarostat 2 watt rv4laysa103a no problem now. I have seen a few post of bias range changing. I have had good luck with the sovtek 5881/6l6wgc but I suspect Russian military tubes from the 1960’s branded sovtek.

[Guy77]

I know this is an old thread but I couldn't resist.
I picked up 2 sets of matched tubes for my Overdrive Special #124 (with 2 tube reverb and marshall 2204 50 watt output transformer).

1st set were JJ 6L6GC, they sounded ok, they had that big bell sound.

2nd set was a pair of Groove Tubes Gold series GT6L6R (this is actually a sovtek 5881)

Well I am going to sell the JJ's on kijiji. The 5881's are a sweeter sounding tube, the JJ's were not as smooth sounding as the 5881's.

I biased and tested both set of tubes a various levels from 19 ma up to 45 ma over several days.

Flame suit properly fitted.

[martin manning]

To Tony's point, they were probably built for a friggin' tank!