[CAJames]

I’m pretty sure Raytheon made 7N7s as well, but I hadn’t heard they made tall bottles.

 

[triod750]

I’m pretty sure Raytheon made 7N7s as well, but I hadn’t heard they made tall bottles.

And I have only heard a tall bottle. So, three obscure tubes making good sound? Has to be fake, through and through.

 

[triod750]

Now using Telefunken branded triple mica 5751 ( might be made by Siemens) into the SFR 6080. The cello and piano is clean, clear and slightly warm with good energy.
Looks like thesebut TFK branded:

I don't recognize the code on the left one.

 

[mordy]

Now using Telefunken branded triple mica 5751 ( might be made by Siemens) into the SFR 6080. The cello and piano is clean, clear and slightly warm with good energy.
Looks like thesebut TFK branded:

I don't recognize the code on the left one.

I think it is a Halske code. If I remember correctly one of the Telefunken factories was Telefunken-Halske.

 

[triod750]

I think it is a Halske code. If I remember correctly one of the Telefunken factories was Telefunken-Halske.

It was Siemens-Halske, München. I can see a symbol like their factory code but the code isn't written as a typical Philips code. But it is in line with my supposition that the tube is made by Siemens.

 

[mordy]

I’m pretty sure Raytheon made 7N7s as well, but I hadn’t heard they made tall bottles.

I think I have solved the mystery of the Raytheon 7N7. Take a look at this:
This is a Raytheon 6Y6G tube from from December 1954. It has the Raytheon EIA code 280 on the base.

Now look at the tube designation and the code underneath the logo:

The code reads C4W. Such three letter codes can only be found on Sylvania tubes. Many Sylvania tubes have two codes - a shipping date code on the base and a manufacturing date code on the glass under the logo.
C4W = March 1954 Factory W.
"Most 7N7 is said to have been produced by Sylvania with some by NU". All loctal 7N7 were made by Sylvania with a few by National Union. Sylvania bought NU around 1952.
The K- R rebrander bought tall bottles 7N7 from Sylvania/NU and had the 280 Raytheon EIA code put on. Just the fact that this rebrander took a name that sounded like Ken-Rad and even made the boxes look like Ken-Rad should speak for itself.
And the pictured tube shows that there are fake EIA codes...

 

[mordy]

It was Siemens-Halske, München. I can see a symbol like their factory code but the code isn't written as a typical Philips code. But it is in line with my supposition that the tube is made by Siemens.

Yes -= must be Siemens-Halske

 

[leftside]

It was Siemens-Halske, München. I can see a symbol like their factory code but the code isn't written as a typical Philips code. But it is in line with my supposition that the tube is made by Siemens.

You got it

 

[triod750]

Yes, and when I examined my tube closely in daylight I could see remnants of the Siemens logo on the other side of the tube. But no Philips code.

 

[JamieMcC]

Crikey no posts since October!

Was having a root around looking for something else and in amongst some boxes of tubes I found a couple of CETRON 7236 tubes

It's the first time I have listened to one in a amp sounding very nice it is to right up there sonics wise with some of the more well known 6as7g 6080 types imo.

 

[DarkDrummer]

What is a 7236? Is it a 6080, or a 6AS7 ? Just wondering, thanks in advance, lol, Bill

 

[Gemini88]

It's different than either of those but is a compatible substitute in some amps. The amplification factor and transconductance are higher than a 6080/6AS7. I think they were made for use in computers

 

[JKDJedi]

What is a 7236? Is it a 6080, or a 6AS7 ? Just wondering, thanks in advance, lol, Bill

Think electronic dance music...

 

[mab1376]

What is a 7236? Is it a 6080, or a 6AS7 ? Just wondering, thanks in advance, lol, Bill

it's a small bottle 5998 basically, some say it's solid-state sounding.

 

[JamieMcC]

Copy and paste from the old cached Bottlehead forum

The 7236 is a computer rated 5998A but should sonically sound similar to the 5998. This specific 7236 has zirconium coated grey box plates. Similar to the 5998 sound abeit more linear, tighter bass and more dynamic. Basically a "faster and controlled" 5998 but at the expense that the bass doesn't go as deep. This tube is glorious listening to vocals and is probably the most controlled and "best" mid-centric tube of the 5998 pack.
…........

As I have a 5998 to compare with I would say that's a pretty accurate description.