[LobalWarming]

So these Visseaux 6L5’s are glass with a metal shroud?

Yes... my 6J5MGs are... don't ask how I know... lol

 

[g0ldl10n]

I just discovered another early tube manufacturer from Pawtucket, Rhode Island - Triad:

https://www.radiomuseum.org/tubes/tube_6c5mg.html
This is what I found:
A second variation has been brought out by Triad Manufacturing Company, Inc., and is illustrated in Fig. D. These metal-glass tubes are known as the MG series and are not all-metal, there being a glass inner sleeve which is used for maintaining the vacuum. Triad was licensed by RCA.


The MG series at present, includes the following types: 5Z4MG, 6A8MG, 6C5MG, 6D5MG, 6F6MG, 6H6MG. 6F7MG, 6K7MG; the characteristics of these tubes are said to parallel those of all-metal construction.

It is very likely that Sears used other sources in addition to NU and Sylvania.
Now, the designation 6C5MG means metal/glass. I don't advise prying off the metal envelope, but most likely this is what you are going to find:

In short, my assumption is that these MG tubes were made by Triad for Arcturus and Sylvania.
https://www.radiomuseum.org/dsp_hersteller_detail.cfm?Company_id=7209

Think this is what @mordy is referring to.. I remember he shared this information to me when I asked questions in regards to some 6C5MG tubes I came into

 

[Monsterzero]

I recently picked up a pair of S/T Visseaux 6J5s. They are excellent in the Airmid, amongst my favs.

 

[triod750]

6L5 is a lower current, slightly lower gain version of the 6J5. Definitely in the family, which includes 6C5 and 6P5. Felix probably feels it's beneath the Envy to burn only 150mA per tube.

I have some TS 6L5G - not my fav of the big twins family... unlike @triod750 who can sing their praises - with low current words.

However have a few Visseaux 6J5MG - which have the same construction as their 6J5G ST bottle. Both versions are in my Top 5 Twins. The Top 5 contains 36 tubes - it's so crowded at the top.

Beautiful exotic hardwood enclosure for your Crack... must make the Envy envious.

Not every 6L5G are the same. I don't enjoy Sylvania for example. So far I only enjoy one and am looking for more of that manufacture. I don't want you to beat me to it

 

[mordy]

Not every 6L5G are the same. I don't enjoy Sylvania for example. So far I only enjoy one and am looking for more of that manufacture. I don't want you to beat me to it

It's a strange fact that with some tubes only one manufacturer/variant sounds good and other tubes with the same designation don't.

 

[triod750]

It's a strange fact that with some tubes only one manufacturer/variant sounds good and other tubes with the same designation don't.

If this is true there are plenty of tubes I don't need to try. Thanks Mordy!

 

[robo24]

Lucked out with 4 of these for $200 on ebay. I have the black base from Langrex but they've always had some noise, mostly a pretty quiet hiss, especially in the Glenn OTL. These brown base are all dead quiet, and the ones on Langrex don't have the labels. Definitely my favorite sounding 6J5, and have always loved the look. The noise kept me from using the black base much but were otherwise my favorites. These on the Envy with WE 300b and the Atrium Closed, oh my! Edit: Oops forgot to say they're Fivre 6C5G.

 

[LobalWarming]

Lucked out with 4 of these for $200 on ebay. I have the black base from Langrex but they've always had some noise, mostly a pretty quiet hiss, especially in the Glenn OTL. These brown base are all dead quiet, and the ones on Langrex don't have the labels. Definitely my favorite sounding 6J5, and have always loved the look. The noise kept me from using the black base much but were otherwise my favorites. These on the Envy with WE 300b and the Atrium Closed, oh my!

Oh... I do love the pasta makers on occasion. Phenomenal bass and awesome looks. My black base pair have never been noisy, in any of my amps. But, I bought them from a quiet seller in a quiet town near Tuscany, not a dreary bangers 'n mash city.

 

[reg66]

Lucked out with 4 of these for $200 on ebay. I have the black base from Langrex but they've always had some noise, mostly a pretty quiet hiss, especially in the Glenn OTL. These brown base are all dead quiet, and the ones on Langrex don't have the labels. Definitely my favorite sounding 6J5, and have always loved the look. The noise kept me from using the black base much but were otherwise my favorites. These on the Envy with WE 300b and the Atrium Closed, oh my!

What tubes are these, please?

 

[OctavianH]

What tubes are these, please?

Fivre 6C5

 

[reg66]

Fivre 6C5

Cheers. Is 6C5 equivalent to 6J5, are they electrically the same and go in the same adapter?

 

[Isaacc7]

Lucked out with 4 of these for $200 on ebay. I have the black base from Langrex but they've always had some noise, mostly a pretty quiet hiss, especially in the Glenn OTL. These brown base are all dead quiet, and the ones on Langrex don't have the labels. Definitely my favorite sounding 6J5, and have always loved the look. The noise kept me from using the black base much but were otherwise my favorites. These on the Envy with WE 300b and the Atrium Closed, oh my!

I use triode wired Fivre 12j7 and have had good luck with them. For me they are an excellent baseline tube that is pretty good at most things. Recently I’ve been enjoying some other tubes that do particular things better but I always have these around.

 

[OctavianH]

Cheers. Is 6C5 equivalent to 6J5, are they electrically the same and go in the same adapter?

Yes. Same adapter.

 

[K3cT]

Hmm... I keep coming back to my trusty straight bottle GEC L63. If I like their sound profile, is the metal base L63 with black glass worth pursuing?

 

[leftside]

Hmm... I keep coming back to my trusty straight bottle GEC L63. If I like their sound profile, is the metal base L63 with black glass worth pursuing?

Yes but pricey now. Two metal base versions: earlier with saucer getter and later with D getter. Both sound the same to me. A little warmer than the later straight clear glass version (which also have two versions: D getter and halo getter).

There is also a version that came inbetween the metal base version and the clear straight glass version - a straight black glass version which is very nice. And of course there is the better known earlier grey glass ST version - which is the first version. Should be pics of all versions earlier in the thread.