5881 and 6L6

GuitarStv

Sock Market Trader
I've always understood that 5881 tubes are the same as 6L6 tubes. Is this the case, or do they sound different? I know that you can swap one for the other with no problems . . .
 
Re: 5881 and 6L6

The way I saw it, they're the 6L6's 6550.
So I'd say firmer low end still, more headroom and more powerful.

I'm not entirely sure but in the EL34 family I'd say it's 34, 6550, KT66 and then on... For the 6L6s, 6L6, 5881, KT88...Dunno for sure though...
 
Re: 5881 and 6L6

I think JJ tubes says the KT77 is the direct replacement for an EL34.:smokin:
And the KT 66 is 6L6 and further, the KT88 is 6550.
 
Re: 5881 and 6L6

DUH sorry haha when Marshall first did the 45, they used what was in the Bassman, then KT66, THEN British valves. Doh.
 
Re: 5881 and 6L6

5881 to my understading were military spec 6l6 type tubes and so they were built with thicker glass etc. made for durability in radios, planes and anything of the sort.
 
Re: 5881 and 6L6

5881's give up the goods more quickly to my ears. They are lower powered 6L6 type tubes. The new production Tung Sol reissues are fantastic tubes, especially at $50 a pair.
 
Re: 5881 and 6L6

I've always understood that 5881 tubes are the same as 6L6 tubes. Is this the case, or do they sound different? I know that you can swap one for the other with no problems . . .

Just make sure you rebias.
 
Re: 5881 and 6L6

The way I saw it, they're the 6L6's 6550.
So I'd say firmer low end still, more headroom and more powerful.

I'm not entirely sure but in the EL34 family I'd say it's 34, 6550, KT66 and then on... For the 6L6s, 6L6, 5881, KT88...Dunno for sure though...

Pierre, what the heck are you talking about?
 
Re: 5881 and 6L6

I think im gonna put some Tung Sol 5881 reissues in my Tweed Twin when the time comes... Just had to throw that in there. And plus 1 to what my man Scott_F said.
 
Re: 5881 and 6L6

I got some Sino's recently ( Shuguang) at 9.00 a pop and they sound great. Really like them.
 
Re: 5881 and 6L6

That plant in China has been churning out some good tubes lately. I'll try them. Thanks for the tip.
 
Re: 5881 and 6L6

I have not heard anything else I like better as far as the new stuff goes. Really good in several of my amps.
 
Re: 5881 and 6L6

I have not, other than a couple pres a friend gave me which are decent, but I tend to prefer the vintage stuff in most cases. The price point on the Shuguang stuff is just too good.
 
Re: 5881 and 6L6

I've always understood that 5881 tubes are the same as 6L6 tubes. Is this the case, or do they sound different? I know that you can swap one for the other with no problems . . .

I agree that the traditional American 5881 is lower headroom compared to typical 6L6 tubes, probably because it's physically smaller throughout. It was originally a small bottle version 6L6 for the US Navy, hence it's millitary/industrial part number.

The Russian (Sovtek/Reflektor) millitary 5881's used extensively in amps during the 90's, are their own thing, and have their own sound, although they also typically have a lower headroom than a typical 6L6. They are not a direct copy of the late 50's early 60's American 5881's used in vintage American amps, although it carries the same ID number.

Different 6L6 tubes could have several different bottle shapes and sizes as well. This is were different subfixes such as GT, GC, GB,... ect... begin to come into play. Ofton, the amount of vacuum (effecting how hot it runs) will vary depending on the bottle design.

The high headroom tube of the 6L6 family is the 7581. 7581's may also carry special part numbers beginning with the letters STR.

Although the British millitary grade KT66 is technically of the 6L6 family, I also really think it's in a class of it's own as far as it's signature sound and response.

A European version of the standard grade 6L6(GT) is the EL37, although they are extemely rare.
 
Re: 5881 and 6L6

So if I get some 6L6's for my Traynor, it will break up later, but still basically sound the same? Do I have to worry about biasing if the amp is supposed to be auto-biased?
 
Re: 5881 and 6L6

5881 are not 6L6 tubes
KT-77 are neither 6550 or El-34 tubes
KT-66 are neither 6L6 or 5881 tubes

There are differences in the heater voltages and output.

For example;
KT-66 takes 1.3 amps while the 6L6 takes 0.9 amps

Tung Sol 5881 puts out 31 ~ 44 watts
RCA 6L6 puts out 24 ~ 32 watts
GEC - KT-66 puts out 28 ~ 50 watts

Push/pull Class AB, all depended on the bais setting, plate voltage etc... (All values adjusted for two tubes)

.
 
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