Favorite 6L6 tubes

JJ' 6L6's have been hit or miss for me. Bought a couple pairs that went bad within 3 months, bought another pair that were microphonic out of the box. Memo to myself: Try tubes out before the return period is up But they're killing in my V4B after over a year.

 

i like winged Cs and have been saving a pair of 6L6s for a special project.

 

JJs, Tung-Sols, Sovteks, EHXs, why pay more?

 

Yes, bucks, of course, but in a truly blind taste test, I dare anyone to hear a difference between these & any ultra-high-price valves.

 

If you buy a current production tube, it will be a 6L6GC. You want a 6L6GC or equivalent in your amp. Just be aware that the 6L6GC is not the same as a 6L6, or a 6L6B, etc.

 

Come on over to my place and I'll run some through my 100T. If you can not hear any difference your ears are shot.

 

Now you have me curious. Could you offer a few words about the differences? Thanks.

 

There were changes made to the design as different materials were discovered. New applications arose. For instance, a 6L6 was a popular radio amplifier tube but then they wanted a higher power version for radio transmitters and jukeboxes. Usually they made the tubes capable of handling a higher plate and screen voltages and dissipating more heat. The original 6L6 could dissipate 19W of heat, plate and screen maximums were 360V and 270V, the 6L6GC can dissipate 30W, the plate and screen maximums were 500V and 450V. A tube capable of dissipating more heat can have more current through it. This allows it to pump out more power. The first 6L6 was developed by RCA and it had a metal outer envelope. Then they released the 6L6G which was a glass tube. Then in the 40's and 50's they came out with GA and GB revisions. These tubes had glass envelopes with different shapes and sizes. The GC came out in the early 50's.

There was a host of tubes that were based on the 6L6. This is why it's such an important tube. The KT66 (more powerful 6L6 intended to be used in transmitters), EL37, 5881 (a smaller 6L6 used initially in aircraft that had a low plate voltage maximum), 7027, 7581, and others.

A 6L6GC can be plugged into an amp that specifies a 6L6 but you can't put a 6L6 into an amp that was designed to use a 6L6GC. An amp that used a 6L6GC might run at 500V, a 6L6 amp may run at 360V. The heater currents drawn are the same.

Bottom line, if you need a 6L6GC in your amp, don't buy a new old stock 6L6.

 

One of the toughest tubes ever is the Sovtek 5881/6L6WGB....its really not a 5881 but it will handle huge plate volts though overall power is just a bit shy of a true 6L6GC.

These have been made in Russia seemingly forever and can be found all over the internet as it was produced under the Russian designation (which escapes me at the moment) as a military spec tube.

All of the other 6L6GC designs from Russia are recent & imo, not as sturdy overall as the lowly Sovtek 5881.

 

Just to be a little more accurate, the commercial equivalent of the 5881 IS 6L6WGB as David points out but it belongs to the earlier 6L6GB family. It puts out less power. As I mentioned in another thread, current production tubes are all over the place with their charateristics.

 

No experience with them, but from what I've read, you can't go from a 6L6 to a 5881 because of the plate voltage being too much for the 5881. But with the Sovtek you can?

 

The Sovtek is not a true 5881/WGB like a vintage USA Tung-Sol or Sylvania 5881/WGB.

It has FAR higher plate volt handling than USA 5881/6L6WGB....it has been widely sold by folks like Lord Valve for use in Mesa, Ampeg, Music Man for years.

I run them in my 73 Carlsbro 60TC which has near 500 plate volts for example.

These were one of the very few rugged 6L6 types that could sub for a 6L6GC and not break a sweat.

They do NOT however have quite as much clean power as a 6L6GC or 7581 which is part of the reason Sovtek chose to label them 5881/6L6WGB.

Any amp tech from the 80's thru now has used a bunch of them at one time or the other.

 

Well that would explain things! Thx David!

 

I've been using JJ's forever in both guitar and bass amps. I even have them in my vintage Bassman heads. Never a failure.

 

I've seen what happens when you put metal envelope 6L6s in an amp designed for GCs.
Luckily there was a fire extinguisher nearby.

 

So, David. Mesa claims that their 5881/6L6 can be run anywhere that a 6L6 can. Do you think that they meet up to the standards of the Sovteks?