[mordy]

S
A

This is all that is on the tubes other than the Arcturus name and I am not even positive the top letter is S for sure as it is a bit worn.

Nobody is going to contradict me on this lol - we just don't know, but here is an uneducated guess. Let's guess that the first letter is the month and the second the year. Going down the alphabet from Jan - Dec and skipping the letter I because it looks like 1, we end up with A through M. Starting again from N through Z S represents May.
Make the A 1940 and SA = May 1940.
I have a 6N7G Arcturus in the original observatory box:

The x-shaped micas are unique. The date code is N 4
R 4
Using the same formula as above, N = January and R = 1938. The truth is that R does not fit into the system, but 4 + 4 = 8. This tube came out in 1936 och Arcturus went bankrupt around 1942 so somewhere in the middle sound about right. I am pretty sure that this is not a rebranded tube because of the mica shape which I could not find elsewhere with 6N7G tubes.

But this is a 6C5 etc thread so back to that. Here is a 6C5MG AirCastle tube which I am sure was made by Arcturus in their Coronet series:

The display stand is included in the price.
https://www.ebay.com/itm/Aircastle-...976022?hash=item217cfe8616:g:sDYAAOSwKwZfqFg-

PS: Please don't take my dating excercise seriously - only intended as a humorous attempt to decipher the unknown.

 

[Velozity]

For anyone curious what the inside of their ST-shaped gray glass L63 looks like but doesn't want to sacrifice a tube to find out, I present to you the somewhat rare clear glass version.

 

[whirlwind]

Nice....thanks for the pics.

 

[leftside]

Been a while since I posted any pictures.

 

[chrisdrop]

Been a while since I posted any pictures.

Love the original boxes for these. That is one area where I've not always had such good luck - getting perfect original boxes.

 

[leftside]

Love the original boxes for these. That is one area where I've not always had such good luck - getting perfect original boxes.

Most of my tubes don't have the original boxes - maybe 10% - 20%. And if they do have the boxes, I tend not to use the tubes and keep them preserved as historical artifacts.

I'll see what other 6J5/L63/etc I have with boxes and post up a pic. I think I have a 6J5 family of GEC/Marconi variation 1/Marconi variation 2/Osram. I think it would be very difficult to collect a "complete set" due to the amount of Marconi and Osram label differences. Then there are all the military versions as well... Even my OCD said "stop - enough is enough" . Same with the KT66 tubes. Funnily enough, there just seems to be two different GEC labels for the KT88 tubes - thankfully!! But, there are multiple construction variations...

 

[OctavianH]

Guys, anyone compared the brown glass Fivre 6C5G from Langrex with black glass Fivre 6C5G? Any difference? How do those sound?
I might make an order to Langrex and I was thinking to grab a pair, I have no idea which one. Many thanks in advance.
I have at the moment only GEC L63 grey glass black base and clear glass brown base and I want to extend a little bit the collection.

 

[chrisdrop]

Guys, anyone compared the brown glass Fivre 6C5G from Langrex with black glass Fivre 6C5G? Any difference? How do those sound?
I might make an order to Langrex and I was thinking to grab a pair, I have no idea which one. Many thanks in advance.
I have at the moment only GEC L63 grey glass black base and clear glass brown base and I want to extend a little bit the collection.

Hey @OctavianH - hope all is well. Looks like you are enjoying tube/amp-land well these days!

Unfortunately, I've not compared black/brown. I have the black ones only and I like them. I think I like them > the Fivre metal base 6J5GTs FYG.

YMMV, etc.

 

[OctavianH]

Hey @OctavianH - hope all is well. Looks like you are enjoying tube/amp-land well these days!

Unfortunately, I've not compared black/brown. I have the black ones only and I like them. I think I like them > the Fivre metal base 6J5GTs FYG.

YMMV, etc.

Yes, I have some new land to explore and this gives me additional excitement and energy. If I remember correctly what you wrote at that time about the Fivre metal base 6J5GT you mentioned those are quite bright and I think you compared them with C3g. Are these black base ones in the same category? Just an idea, for me GEC L63 brown base clear glass is warm, full bodied.

 

[chrisdrop]

The metal base 6J5GT in the GOTL at least was lacking some "oomph" in the lower end or warmth in general perhaps. That said, perhaps I was too aggressive in saying they were C3G-like. In the Blue Halo, they are a bit more balanced/good. The GEC L63 brown-base tubes are not so much warm IMO, maybe a touch, but they are nicely bodied as you say. Does your current amp have CCS or not? My GOTL didn't have CCS in it and the Blue Halo does. It makes a difference in how I've interpreted these tubes. Many older comments come from the GOTL, more recently on the Blue Halo. I can tailor comments a bit better if I understand CCS/no-CCS and I can guess/extrapolate to your current listening environment. Perhaps you have one of those amps where you change the settings to be biased for each tube and so on?

 

[OctavianH]

As far as I know my amp does not have CCS, but I am able to bias it manually. Not per tube, but per stage (this means all outputs or all inputs). To be able to bias closely a pair, I usually find a medium value for the grid bias voltage in order for a tube to achieve a specific desired current level and adjust it. I come from the "auto-bias" world, so this mechanism is something new for me. But I learn.

 

[raindownthunda]

The metal base 6J5GT in the GOTL at least was lacking some "oomph" in the lower end or warmth in general perhaps. That said, perhaps I was too aggressive in saying they were C3G-like. In the Blue Halo, they are a bit more balanced/good. The GEC L63 brown-base tubes are not so much warm IMO, maybe a touch, but they are nicely bodied as you say. Does your current amp have CCS or not? My GOTL didn't have CCS in it and the Blue Halo does. It makes a difference in how I've interpreted these tubes. Many older comments come from the GOTL, more recently on the Blue Halo. I can tailor comments a bit better if I understand CCS/no-CCS and I can guess/extrapolate to your current listening environment. Perhaps you have one of those amps where you change the settings to be biased for each tube and so on?

Hey @chrisdrop have you had a chance to compare the Fivre 6C5G shouldered vs straight tubes? I'm a huge fan of the Five 6C5G shouldered tubes and was wondering if it would a redundant purchase and or if you prefer one over the other.

 

[leftside]

In general I find 6C5 and 76 to have a lighter and more airy sound than 6J5 with my amp and gear

 

[triod750]

In general I find 6C5 and 76 to have a lighter and more airy sound than 6J5 with my amp and gear

I have almost zero experience with 6J5/6C5. They are new territory for me. I have only listened to a pair of 'Brimar' branded 6J5GT/G mentioned previously, and now one JAN-CRC-6C5, one JAN-CKR-6C5, these two 6C5 as a pair, and just swapped the Ken-Rad for a 6J5G 'S.T.C. 101' 10 E/348 supposed to be Brimar. My impression with this is contrary to leftsides; the 6C5 is meatier than 6J5/6J5G. Might be the Ken-Rad? As I said - zero experience. Just wanted to share that zero experience. Thats is where you all started.
I have three meatball JAN-CRC-6C5 so I will do a proper session with them later. Just mixing and unmatching right now. The 6J5G was a gift from the person that sold me the 6C5. It had a broken key. That sounds 'orrible. Have to find another.

This is how it looks but I will not buy this. I want another as cheap as the first one: https://www.ebay.co.uk/itm/265017950134?hash=item3db44cffb6:g:SdoAAOSwiAZgBJ49

 

[OctavianH]

Does your current amp have CCS or not?

I think my answer from yesterday was not correct, so I had to ask and come back with a proper answer. I have to admit that I am no expert in tube amp design and I just scratch the surface. I use at the moment an amplifier made by UltraSonic Studios, I have asked and found that it does have a couple of CCSs inside as well as the grid drivers are CCS loaded. When I answered yesterday I was thinking at a previous discussion when he told me my amp will not have the CCS tail of the other designs.

I think I'll have to read more from The Valve Wizard!