The Reference 6SN7 Thread

[TLO]

As a general advice, if you see on a tube printed IMPORT or FOREIGN that means they were rebranded and imported or manufactured in other place than the logo.

Yes, I am aware of that. I am just pointing out there is a mention of this tube is Made in USSR in the listing description.

 

[walterboss]

Yes, I am aware of that. I am just pointing out there is a mention of this tube is Made in USSR in the listing description.

I was aware they were Russian. I was just trying to establish if the seller was pulling a fast one listing them as CV1988 (which are recommended as a pairing for my WE300b, knowing these were just a cheap backup CV1988) or something that was actually totally different or incompatible.

 

[LobalWarming]

Brimar made dual triode 30L15 (MAZDA labeled) but you will need adapter on 6SN7.

B-b-but those are kiddie's tubes. Not big manly octals.

However, Brimar made some good kiddie's tubes, like 4033, 6060 or the little twin CV133s.

 

[TLO]

B-b-but those are kiddie's tubes. Not big manly octals.

However, Brimar made some good kiddie's tubes, like 4033, 6060 or the little twin CV133s.

But part of the fun in tube rolling is to find a small tube, especially no one has tried before, with great sound at dirt cheap price..lol

 

[turbofeet]

Hello all.
I have had a lovely Melz 1578 matched pair for a few years now and they are still probably my favourite 6SN7s. I have had the pins resoldered (twice!) and they are dead silent and just perfect except for a minor issue which I mention below. They are fine examples of this tube but I have a couple of questions if I may...

Date of manufacture
If you look at the attached pics I am actually trying to determine the date of manufacture. The golden print in the first picture reads "6H8C X-76". I know it may seem very obvious but I assume the date of manufacture is 1976? Other markings on the tube are "OTK 23", "37" and "19" in a diamond logo. I think some of these indicate a simple quality assurance code but i'm not sure.

Stainless Steel Rods
Second question is that I note that the rods on mine are stainless steel. Well they are shiny. Looking at the 4th post here this fellow says this is a sign that they are the genuine Melz. However I see a lot of these where the rods do not appear to be stainless steel (not even in the picture in his post). These rather expensive ones do not seem to have stainless steel rods either. It may be that the pictures aren't picking it up but does this mean they are not genuine or just not the best versions? I would never pay that much for the tubes anyway but just curious. I know some people aren't as impressed with these as I am so perhaps some of these factors play a part.
I am quite curious about these as they look identical to the super expensive pair in construction. I appreciate they don't say 1578 on then either and are the 68NS variant but they have the "mouse ears" and the plates with the slight rectangular ledge.

Loose Base
The black base is very slightly loose at the base of one tubes. I have indicated where with a red box. It is a very tiny amount of play and it still works fine. I am not concerned about it however I would like to try and fix it so it doesn't get worse. I suspect it's because they have been rolled in and out a number of times and I would always pull them out by the metal base. Potentially I should have held them from the black plastic base instead. I use the woo audio ceramic socket savers.
I have been reading this thread and bought some superglue as well as an epoxy stick. The thing is, the play is probably less that 1mm so the Epoxy does seem overkill - especially as that area won't get hot so I don't think i'll use that.

Should I just apply some superglue in the gap between the metal and the plastic base? Or just leave it alone?

Thanks in advance

 

[TLO]

Hello all.
I have had a lovely Melz 1578 matched pair for a few years now and they are still probably my favourite 6SN7s. I have had the pins resoldered (twice!) and they are dead silent and just perfect except for a minor issue which I mention below. They are fine examples of this tube but I have a couple of questions if I may...

Date of manufacture
If you look at the attached pics I am actually trying to determine the date of manufacture. The golden print in the first picture reads "6H8C X-76". I know it may seem very obvious but I assume the date of manufacture is 1976? Other markings on the tube are "OTK 23", "37" and "19" in a diamond logo. I think some of these indicate a simple quality assurance code but i'm not sure.

Stainless Steel Rods
Second question is that I note that the rods on mine are stainless steel. Well they are shiny. Looking at the 4th post here this fellow says this is a sign that they are the genuine Melz. However I see a lot of these where the rods do not appear to be stainless steel (not even in the picture in his post). These rather expensive ones do not seem to have stainless steel rods either. It may be that the pictures aren't picking it up but does this mean they are not genuine or just not the best versions? I would never pay that much for the tubes anyway but just curious. I know some people aren't as impressed with these as I am so perhaps some of these factors play a part.
I am quite curious about these as they look identical to the super expensive pair in construction. I appreciate they don't say 1578 on then either and are the 68NS variant but they have the "mouse ears" and the plates with the slight rectangular ledge.

Loose Base
The black base is very slightly loose at the base of one tubes. I have indicated where with a red box. It is a very tiny amount of play and it still works fine. I am not concerned about it however I would like to try and fix it so it doesn't get worse. I suspect it's because they have been rolled in and out a number of times and I would always pull them out by the metal base. Potentially I should have held them from the black plastic base instead. I use the woo audio ceramic socket savers.
I have been reading this thread and bought some superglue as well as an epoxy stick. The thing is, the play is probably less that 1mm so the Epoxy does seem overkill - especially as that area won't get hot so I don't think i'll use that.

Should I just apply some superglue in the gap between the metal and the plastic base? Or just leave it alone?

Thanks in advance

Fixing loose base...
https://www.head-fi.org/threads/the-reference-6sn7-thread.117677/post-16829305

 

[JackarlTwo]

OK - back to real tubes again. In these days of ever escalating prices of desirable tubes I have found a garden variety RCA 6SN7GT that IMHO is a top tier tube. This tube should be inexpensive but it is a little hard to find but not because it is rare; I'll explain:
This 6SN7GT tube is from the late sixties. RCA made several different such tubes, but I only found one variant that sounds great. This variant has a little heater wire above the top mica and black parallel plates. All the ones I have seen have red print on the base. There are also rebranded such tubes that should make them even cheaper (I have pair Stromberg-Carlson branded ones - S-C was a radio manufacturer). The problem is that most such tubes when pictured in the ads don't show that little heater wire. Here is a spotters guide:

My tube in action; more pictures below:




If anyone has this variant, please try it and let me know what you think of the sound.

I actually bought those in the pictures. Price didn't seem bad at all so I jumped on it. It'll be a while until I can try them out.

 

[mordy]

Hello all.
I have had a lovely Melz 1578 matched pair for a few years now and they are still probably my favourite 6SN7s. I have had the pins resoldered (twice!) and they are dead silent and just perfect except for a minor issue which I mention below. They are fine examples of this tube but I have a couple of questions if I may...

Date of manufacture
If you look at the attached pics I am actually trying to determine the date of manufacture. The golden print in the first picture reads "6H8C X-76". I know it may seem very obvious but I assume the date of manufacture is 1976? Other markings on the tube are "OTK 23", "37" and "19" in a diamond logo. I think some of these indicate a simple quality assurance code but i'm not sure.

Stainless Steel Rods
Second question is that I note that the rods on mine are stainless steel. Well they are shiny. Looking at the 4th post here this fellow says this is a sign that they are the genuine Melz. However I see a lot of these where the rods do not appear to be stainless steel (not even in the picture in his post). These rather expensive ones do not seem to have stainless steel rods either. It may be that the pictures aren't picking it up but does this mean they are not genuine or just not the best versions? I would never pay that much for the tubes anyway but just curious. I know some people aren't as impressed with these as I am so perhaps some of these factors play a part.
I am quite curious about these as they look identical to the super expensive pair in construction. I appreciate they don't say 1578 on then either and are the 68NS variant but they have the "mouse ears" and the plates with the slight rectangular ledge.

Loose Base
The black base is very slightly loose at the base of one tubes. I have indicated where with a red box. It is a very tiny amount of play and it still works fine. I am not concerned about it however I would like to try and fix it so it doesn't get worse. I suspect it's because they have been rolled in and out a number of times and I would always pull them out by the metal base. Potentially I should have held them from the black plastic base instead. I use the woo audio ceramic socket savers.
I have been reading this thread and bought some superglue as well as an epoxy stick. The thing is, the play is probably less that 1mm so the Epoxy does seem overkill - especially as that area won't get hot so I don't think i'll use that.

Should I just apply some superglue in the gap between the metal and the plastic base? Or just leave it alone?

Thanks in advance

Many Russian tubes use Roman numerals for the month - X = 10 which is October. 76 = 1976.
It is very easy to fix a loose base. Drop in a tiny amount of superglue between the socket and the glass, hold it in place for a minute and then put the tube standing up to dry in a secure place overnight.
It is not unusual for old glue to dry out and the fix is very easy.

 

[mordy]

I actually bought those in the pictures. Price didn't seem bad at all so I jumped on it. It'll be a while until I can try them out.

Please let us hear your impressions when you get them.

 

[turbofeet]

Many Russian tubes use Roman numerals for the month - X = 10 which is October. 76 = 1976.
It is very easy to fix a loose base. Drop in a tiny amount of superglue between the socket and the glass, hold it in place for a minute and then put the tube standing up to dry in a secure place overnight.
It is not unusual for old glue to dry out and the fix is very easy.

Thanks for that. Very helpful

 

[triod750]

Just to clarify the terminology: we all commonly refer to the getter holder as the getter (as in square getter, round getter, foil getter, etc.). That is merely the structure inside the tube that holds the getter material (usually in the form of a pellet or tablet), until it is flashed in the last stage of the manufacturing process. The flashing process vaporizes this pellet and deposits the material in a thin coating inside the glass which is usually silver, but can be black (Russian tubes) or brown (some Euro tubes). But the flashing process normally vaporizes all of this material, and unless there is some getter material leftover after the original flashing process (which would be very unusual), there is nothing there to "re-flash."

Where do you have the getter flash in these very good sounding tubes with bottom rectangular getter holder?

 

[TLO]

Where do you have the getter flash in these very good sounding tubes with bottom rectangular getter holder?

If you look carefully, you can see the shiny flash at the bottom of the glass.

 

[turbofeet]

Many Russian tubes use Roman numerals for the month - X = 10 which is October. 76 = 1976.
It is very easy to fix a loose base. Drop in a tiny amount of superglue between the socket and the glass, hold it in place for a minute and then put the tube standing up to dry in a secure place overnight.
It is not unusual for old glue to dry out and the fix is very easy.

The glue worked a treat!

 

[triod750]

If you look carefully, you can see the shiny flash at the bottom of the glass.

Will I have to sneak up on it not to scare it away?

 

[triod750]

If you look carefully, you can see the shiny flash at the bottom of the glass.

You mean on the glass pinch?