[gibosi]

Don’t forget to get some el cheapo Sylvania 7n7.

And you will find Sylvanai 7N7 with the older GT plates as well as the newer GTA plates....

 

[UntilThen]

And the 7F7 if you can find it.

 

[gibosi]

And the 7F7 if you can find it.

And don't forget the 12 volt versions:

14N7, 14F7 and also, 14AF7

 

[UntilThen]

Alright getting an overdose.

 

[whirlwind]

Trying out different combinations in the amp.

Plug back in the 4 x Chatham 6AS7Gs and loving the synergy it has with HD650s.

Take out the 12SN7 Sylvania and think it couldn't get better.

Go back into the box of goodies and finally decide to pop in the Siemens c3gs. All I have to say is:

I have a few sets of the Chatham 6AS7G tubes and I will definitely be trying four of these in my amp.

 

[Althalus]

Back to an earlier discussion.

After the discussion a while ago about the 6n7 I decided to buy some for my coming gotl.
I got today 2 metal ones, labelled Sylvania and three cokebottles. 2 different labelled, but identical looking with 4 pairs of pins on top and the stopsign on the glass. One says Ken-Rad with the Code 08 the other GM, genuine parts and Code S7. The third one reads Ken-Rad with code TD and has no markings on the glass and the 4 pairs of pins on top have small plates attached to them.
Does anybody know how I can see who manufactured them?

 

[Althalus]

 

[Phantaminum]

I have a few sets of the Chatham 6AS7G tubes and I will definitely be trying four of these in my amp.

I like it more lush than neutral. With Chathams and c3g it gives the best of both worlds on the HD650. Very detailed, tight, with a full body. I’ve been wondering how this combination sounds with the Atticus. I can imagine feeling those snare hits and kick drums as if your were there.

 

[gibosi]

Back to an earlier discussion.

After the discussion a while ago about the 6n7 I decided to buy some for my coming gotl.
I got today 2 metal ones, labelled Sylvania and three cokebottles. 2 different labelled, but identical looking with 4 pairs of pins on top and the stopsign on the glass. One says Ken-Rad with the Code 08 the other GM, genuine parts and Code S7. The third one reads Ken-Rad with code TD and has no markings on the glass and the 4 pairs of pins on top have small plates attached to them.
Does anybody know how I can see who manufactured them?

The only way to know the manufacturer for sure is to compare construction. For me, this usually involves comparing the tube I have in my hands to lots of pictures on the web. However, I don't have any 6N7G and therefore, I haven't studied them...

Ken-Rad's prewar date codes were one letter and one number. The code "08" is strange. The letter "O" was omitted given that it could be confused with the number "0". So this code combination wasn't used. Further, the Delco with Code S7, also doesn't fit. The codes for 1937 went from A7 to L7. By 1947, GE had purchased Ken-Rad and I am not sure if they were still using this date code after the war. And your third tube, with Code TD also doesn't fit. Maybe some of the others here, who actually have some 6N7G might be able to help.

As for the Sylvania metal tubes. Look for letters and numbers embossed on the side of the base. For example, the RCA pictured below, on the left, "6N7" and "H4". The Ken-Rad on the right, "13-". I am not positive that Sylvania even manufactured the metal 6N7, but if they did I would assume that they too would have embossed identifying marks of some kind in the event that all the painted markings were missing.

Good luck!

 

[Althalus]

The only way to know the manufacturer for sure is to compare construction. For me, this usually involves comparing the tube I have in my hands to lots of pictures on the web. However, I don't have any 6N7G and therefore, I haven't studied them...

Ken-Rad's prewar date codes were one letter and one number. The code "08" is strange. The letter "O" was omitted given that it could be confused with the number "0". So this code combination wasn't used. Further, the Delco with Code S7, also doesn't fit. The codes for 1937 went from A7 to L7. By 1947, GE had purchased Ken-Rad and I am not sure if they were still using this date code after the war. And your third tube, with Code TD also doesn't fit. Maybe some of the others here, who actually have some 6N7G might be able to help.

As for the Sylvania metal tubes. Look for letters and numbers embossed on the side of the base. For example, the RCA pictured below, on the left, "6N7" and "H4". The Ken-Rad on the right, "13-". I am not positive that Sylvania even manufactured the metal 6N7, but if they did I would assume that they too would have embossed identifying marks of some kind in the event that all the painted markings were missing.

Good luck!

Hi Gibosi, Thank you.
I did take a look at the metal Sylvania .
The base shows nothing exept small traces of oxidation of the metal.
On the tubes itself is in green the leaf, the name Sylvania with underneath made in USA , a stopsign with 6n7. And a code , Z1 for one tube, VOR for the other .
Under the base is the text "licenced only to extent indicated on carton".

And one tube came in original box, but I can't see anything as the standard printing, no numbers or dates.

I checked the cokebottles again .TD might be TO or T0
For the identical GM/Ken-Rad I do include these pictures, showing the stopsign and the codes on the base.

 

[Thaddy]

Is Glenn still taking order for tube amps? What's the process to go about acquiring one?

 

[2359glenn]

Is Glenn still taking order for tube amps? What's the process to go about acquiring one?

Send me a PM
Glenn

 

[gibosi]

I did take a look at the metal Sylvania .
The base shows nothing exept small traces of oxidation of the metal.
On the tubes itself is in green the leaf, the name Sylvania with underneath made in USA , a stopsign with 6n7. And a code , Z1 for one tube, VOR for the other .
Under the base is the text "licenced only to extent indicated on carton".

And one tube came in original box, but I can't see anything as the standard printing, no numbers or dates.

I checked the cokebottles again .TD might be TO or T0

T0 is a valid Ken-Rad date code, May, 1941. However, this was not the date of manufacture, it was the date the manufacturer's warrantee expired. So the tube was likely manufactured about 12 months earlier.

The Sylvania codes are also valid. Z1 indicates the second quarter of 1941. And V0R indicates the third quarter of 1940. R indicates that it was sold as a replacement tube. That is, it was not installed in a radio at the time of purchase.

And regarding the other two, 08 and S7, even though they do not conform to Ken-Rad's prerwar code, given that the bases are not hot-stamped, but silk-screened, I would guess 08 = 1948 and S7 = 1947. GE took control of Ken-Rad in 1945, but continued to use the Ken-Rad brand for replacement tubes until at least 1950. It is my understanding that in 1948, GE began to use Y-MM pattern for dating, but between 1945 to 1948, it would seem that something different was being used on Ken-Rad tubes. But of course, I don't know for sure, I can only speculate....

 

[Althalus]

T0 is a valid Ken-Rad date code, May, 1941. However, this was not the date of manufacture, it was the date the manufacturer's warrantee expired. So the tube was likely manufactured about 12 months earlier.

The Sylvania codes are also valid. Z1 indicates the second quarter of 1941. And V0R indicates the second quarter of 1940. R indicates that it was sold as a replacement tube. That is, it was not installed in a radio at the time of purchase.

And regarding the other two, 08 and S7, even though they do not conform to Ken-Rad's prerwar code, given that the bases are not hot-stamped, but silk-screened, I would guess 08 = 1948 and S7 = 1947. GE took control of Ken-Rad in 1945, but continued to use the Ken-Rad brand for replacement tubes until at least 1950. It is my understanding that in 1948, GE began to use Y-MM pattern for dating, but between 1945 to 1948, it would seem that something different was being used on Ken-Rad tubes. But of course, I don't know for sure, I can only speculate....

Thanks a lot gibosi, your knowledge is very usefull for me. You know more than I could find on the net.

Second quarter of 1940 and May 1940, that's when ww2 started. These must be my oldest tubes so far.

 

[mordy]

I would like to tell about an amazing customer service experience. My Beyerdynamic T1 Gen1 headphones got damaged from a bad tube and the left driver went out.
I contacted the Beyerdymanic aurthorized factory service United Sound Services in MA. They told me that a new set of drivers out of warranty would cost $250. However,
"For the budget minded we do have some left over used ones from previous repairs that we can try and match to your right side."
Mailed out the headphones Monday and they just came back today Friday. The invoice stated that the technician found a good match.The total bill parts and labor including shipping both ways, was less than $60.
Super nice people and extremely quick turn around.