The Reference 6SN7 Thread

[JTbbb]

How about this on? VT231 marking in second photo…
https://www.ebay.com/itm/335162275818

Hahaha, I knew a pic would appear! Thanks. Does this designation refer to wartime production?

 

[reg66]

Thank you for the photos, all nice tubes. What piqued my interest was the vt-231 designation as I don’t recall seeing a Ken Rad marked as such. Perhaps there is such a tube? I’m sure a pic will appear forthwith! Or maybe it’s a generalisation for this type of tube?

Ahh i see, didn't realise you wanted the VT-231 part... Here ya go

Top left tube has it too (not shown) but it's pretty faint

 

[TLO]

Hahaha, I knew a pic would appear! Thanks. Does this designation refer to wartime production?

Mine were all dated 1943

 

[reg66]

Hahaha, I knew a pic would appear! Thanks. Does this designation refer to wartime production?

I may be way off target here, but i thought the wartime designation was 'C' ie CKR for Ken Rads, CHS for Sylvania, CTL for Tung Sol etc... Maybe the VT-231 forms part of that same wartime designation too, i'm not sure tho

EDIT: quick Google: https://www.head-fi.org/threads/the-6sn7-identification-guide.209782/post-15934897

Looks as though you're correct - VT231 are wartime tubes. See the post below the linked one also, says about JAN designation too

 

[David A Silva]

I may be way off target here, but i thought the wartime designation was 'C' ie CKR for Ken Rads, CHS for Sylvania, CTL for Tung Sol etc... Maybe the VT-231 forms part of that same wartime designation too, i'm not sure tho

All KR VT231 I have seen ( maybe 6-7 ) are marked CKR…

 

[reg66]

All KR VT231 I have seen ( maybe 6-7 ) are marked CKR…

Can they not all be from wartime, then? Seems both the 'C' and the VT are a combination wartime designation

 

[TLO]

I may be way off target here, but i thought the wartime designation was 'C' ie CKR for Ken Rads, CHS for Sylvania, CTL for Tung Sol etc... Maybe the VT-231 forms part of that same wartime designation too, i'm not sure tho

VT-231 was a US military inventory control number, VT believed to be Vacuum Tube and 231 was for 6SN7 GT

 

[JTbbb]

I may be way off target here, but i thought the wartime designation was 'C' ie CKR for Ken Rads, CHS for Sylvania, CTL for Tung Sol etc... Maybe the VT-231 forms part of that same wartime designation too, i'm not sure tho

EDIT: quick Google: https://www.head-fi.org/threads/the-6sn7-identification-guide.209782/post-15934897

Looks as though you're correct - VT231 are wartime tubes. See the post below the linked one also, says about JAN designation too

Oh dear! Maybe mine do have VT-231….under the label, and I have forgotten all about it .

Edit: Same situation with a singleton I have!

 

[reg66]

Oh dear! Maybe mine do have VT-231….under the label, and I have forgotten all about it .

Edit: Same situation with a singleton I have!

Haha! Definitely possible!!!

 

[Isaacc7]

What differences between B36 and your favorite 12sn7? Thanks!

My system has a lot of tubes so it isn’t always easy to pin a specific sound to a tube. I tend to think in terms of tube combos these days. The Fivre made b36 and actual MOV b36 sound pretty similar to me when I swap between them. I like them the most when paired with RCA 6bg6ga tubes run in triode mode. I have also enjoyed them at times in my preamp with a variety of combos in my tube amps.

My favorite 12sn7 is probably the humble 14n7. I find them the most likely to give me a good sound with a wide variety of other tubes. As far as I can tell they are analogs of the coveted metal based Sylvania 6sn7w complete with copper support rods. Those 6sn7w tubes have a sterling reputation but are now really expensive so I don’t have a way to compare them sonically. Since they are constructed the same and I like the 14n7 better than any of the other Sylvania 6sn7w, vt31, bottom getter, top getter, bad boys, etc. I’m willing to bet they are the same as the metal 6sn7w. Tall bottle, short bottle, it doesn’t seem to matter with the 14n7. Possibly excepting grey glass versions. Haven’t had any luck with them or the sylvania grey glass 7n7.

 

[Isaacc7]

Yes those are Fivre. I'm selling a pair of these also from Langrex in classifieds. There have been different construction for the Italien Fivre/Marconi 6sn7gt variants.


Let me see the date and manufacturers code on the back of your tube. The sticker is genuinely from MWT England (GEC).

Here you go:

 

[g0ldl10n]

Yes, the Marconi's were made at either the Calgary or Montreal factories. The operating company was Radiotron Valve Company(RVC) They bought licenses from RCA and Sylvania. But just like Visseaux using Sylvania licenses in Lyon, France, RVC made tubes that have a unique and individual sound. Maybe the metals they used where a little different? But they definitely have a secret sauce to them. I love them!!

They are available with the following names that I've encountered.

Marconi Canada
General Electric Canada
Westinghouse Canada
Rogers Canada
Sylvania Canada
RCA Canada

Maybe more???

But they all have this raised and ultra sturdy made structure with a foil D getter, in a tall bottle. They also all have 6SN7 made in Canada that's been acid etched on the glass envelope.

Sonically they are slightly warm with a tremendous slap of deep and extremely extended bass. I use these as my driver tubes in my Cayin HA-300B MKII - 300B amp, paired with the very linear Elrog ER300B-Mo. They seem to add a touch of soul to the technical Elrog.

I also use this tube as a driver into my Studio Six paired with Visseaux 6V6Gs. The Studio Six is tuned also in a very linear way and the touch of warmth with deep bass pairs very well with the Visseaux that has a beautiful harmonic complexity. It's a really refined, complex and addictive sound.

Without getting into the mega bucks 6SN7s, and I own the many of them. I think this might be my desert island 6SN7. They are available, hint if you can't find them on Ebay and I'd be surprised if you don't find them. Then go the the Ebay Canada site. They are pretty common. I see pairs go for as low as $40.00 that test good. NOS testing pairs can go for closer to $80.00. Still a deal in my book.

Note, I run a Delta Sigma DAC, the Weiss DAC501-4Ch. I have detail to spare. As I said I run an Elrog 300B that's known to be very very revealing. These Canadian made 6SN7s might smear a little in the upper bass to the low mid-range. Just a tad. But with the system and amps I've assembled it's really not anything to think about. As I've said, I have resolution to spare. But at this moment in time and probably for the last few years, I'd say that this is my personnal desert island 6SN7.

Speaking of Canadian tubes, I recently received this quad of 6SN7GT tubes - the internals certainly look like Sylvania 6SN7WGT with parallel T-Plates and support rod but the base says 'PAT. CANADA' - unsure if these were actually made in Canada or not, do you have any idea? They do not have 'Canada' under the 6SN7GT logo on the top of them.

 

[g0ldl10n]

Speaking of Canadian tubes, I recently received this quad of 6SN7GT tubes - the internals certainly look like Sylvania 6SN7WGT with parallel T-Plates and support rod but the base says 'PAT. CANADA' - unsure if these were actually made in Canada or not, do you have any idea? They do not have 'Canada' under the 6SN7GT logo on the top of them.

Adding to this, the boxes say the tubes are tested and packaged in the United States, but they also state "Country of origin as marked on the tube".

Lol, so I still have no idea.. but I would find it logistically strange if Canada manufactured the tubes in one of their factories then sent them the US to have them tested and packaged, then shipped back to Canada to sell

 

[TLO]

Adding to this, the boxes say the tubes are tested and packaged in the United States, but they also state "Country of origin as marked on the tube".



Lol, so I still have no idea.. but I would find it logistically strange if Canada manufactured the tubes in one of their factories then sent them the US to have them tested and packaged, then shipped back to Canada to sell

Perhaps these are not the original boxes or the tubes were bought and repacked in these boxes at later date to be sold in the US
Check: https://en.wikipedia.org/wiki/Rogers_Vacuum_Tube_Company

 

[RobertSM]

Speaking of Canadian tubes, I recently received this quad of 6SN7GT tubes - the internals certainly look like Sylvania 6SN7WGT with parallel T-Plates and support rod but the base says 'PAT. CANADA' - unsure if these were actually made in Canada or not, do you have any idea? They do not have 'Canada' under the 6SN7GT logo on the top of them.

I have these same tubes. The only difference I see is my tubes have Rogers printed in green.

I bought them pre pandemic from a guy in Vancouver. I want to say they were very fairly priced. It was a bigger buy for me because I remember he sold them as a lot of 7-8 6SN7s. I don't remember having listened to them at all. I'll have to look for them and give them a listen soon. How do you like them?

The interesting thing with some of the Canadian made tubes, is that there were some made in the 70's that say they were made in Canada that I think were actually made in Japan. As far as I know by the early 1970's most of the few Canadian tube factories were shutting down. I think Japan was taking over most of the tube production.