[leftside]

Is there much difference between these tubes in terms of sound? I understand the QDD means it's from another factory?

https://www.langrex.co.uk/products/6080-cv2984-mullard-qdd-nos-boxed-valve-tube/

https://www.langrex.co.uk/products/6080-mullard-grade-1-valve-tube/

Both look later versions from the 70's with the halo getter. Probably same factory. I'd buy the military ones, as the pins look quite corroded on the others.

 

[gibosi]

To the best of my knowledge, all Mullard 6080 were manufactured in their Mitcham factory: code = R. It is unfortunate, that the pictures do not show factory codes. Both appear to have the same construction with halo getters, and I would expect that they sound the same.

 

[u2u2]

Both look later versions from the 70's with the halo getter. Probably same factory. I'd buy the military ones, as the pins look quite corroded on the others.

I have two pair of each of the variants posted. Also from Langrex some 7 or 8 years ago. My understanding is both versions were made at Mitchum. AJ1 R3K for the CV2984s, 6080s are AJ1 and various R#!#. If I were to buy more I would get the CV2984 for sure due to the certainty of it being true NOS and the wrapping/box it will arrive in plus there may be matching codes as was my case. Won't claim I can detect a sound difference between them. They deliver on the WA22.

 

[JackarlTwo]

It arrived the other day. Great condition! Not tested yet. I also picked up a pair of GEC CV4079.

 

[Renexx]

It arrived the other day. Great condition! Not tested yet. I also picked up a pair of GEC CV4079.

Nice military Mullard 6080s.

I finally got my hands on a rare 40s or 50s Tungsol 5998 pair.
Rectangular bottom getter and matte grey domino plates. The top mica construction looks like a WE421A.

 

[JTbbb]

Nice military Mullard 6080s.

I finally got my hands on a rare 40s or 50s Tungsol 5998 pair.
Rectangular bottom getter and matte grey domino plates. The top mica construction looks like a WE421A.

The rectangular top mica supports are also a giveaway of early production. Nice tubes.

 

[bcowen]

It arrived the other day. Great condition! Not tested yet. I also picked up a pair of GEC CV4079.

Nice!!

 

[bcowen]

Nice military Mullard 6080s.

I finally got my hands on a rare 40s or 50s Tungsol 5998 pair.
Rectangular bottom getter and matte grey domino plates. The top mica construction looks like a WE421A.

Also nice!

Got a pair of IBM-branded Tung-Sol 5998's a while back from a super cool guy that frequents this thread (but don't want to say who so I don't get @JTbbb in trouble ). Best testing 5998's I have with nearly perfectly balanced triodes, which is the exception rather than the rule with most 5998's and 6AS7G's. Still enjoying them!

 

[Promee]

I finally got my hands on a rare 40s or 50s Tungsol 5998 pair.

I am excited for you and the weekend of listening you must be launching into

 

[Renexx]

I am excited for you and the weekend of listening you must be launching into

Thanks, I would say the early version doesn't sound different than my later Tungsol 2399 top getter. 2399 is only an inventory number for 5998 tubes but still lovely to find such a pair in original boxes. Both pairs make a collector happy.

 

[JTbbb]

Also nice!

Got a pair of IBM-branded Tung-Sol 5998's a while back from a super cool guy that frequents this thread (but don't want to say who so I don't get @JTbbb in trouble ). Best testing 5998's I have with nearly perfectly balanced triodes, which is the exception rather than the rule with most 5998's and 6AS7G's. Still enjoying them!

Pleased you’re enjoying them! Am even more pleased you have validated the chap I send my tubes to for testing.

 

[mordy]

Nice military Mullard 6080s.

I finally got my hands on a rare 40s or 50s Tungsol 5998 pair.
Rectangular bottom getter and matte grey domino plates. The top mica construction looks like a WE421A.

Tung Sol acquired Chatham in the mid 50's so the date should be March 1958 (8-14).

 

[gibosi]

Tung Sol acquired Chatham in the mid 50's so the date should be March 1958 (8-14).

A little more info....

The 4-digit Special Purpose code designation for WE's 421A, "5998," was reserved with the RTMA (Radio-Televsion Manufacturers Association) in August, 1950. Thus, there were no 5998's before that date. And the very first 5998's were in fact, WE 421A. It's not clear when WE and Chatham worked out an arrangement allowing Chatham to manufacture the 5998. The earliest 5998s I have are dated 1957, week 10 (7-10). If anyone has older ones, please let me know.

 

[VanHai]

A little more info....

The 4-digit Special Purpose code designation for WE's 421A, "5998," was reserved with the RTMA (Radio-Televsion Manufacturers Association) in August, 1950. Thus, there were no 5998's before that date. And the very first 5998's were in fact, WE 421A. It's not clear when WE and Chatham worked out an arrangement allowing Chatham to manufacture the 5998. The earliest 5998s I have are dated 1957, week 10 (7-10). If anyone has older ones, please let me know.

My pair of Tung-Sol 5998 has code 55-35. So must be 1955 week 35?.

 

[mordy]

A little more info....

The 4-digit Special Purpose code designation for WE's 421A, "5998," was reserved with the RTMA (Radio-Televsion Manufacturers Association) in August, 1950. Thus, there were no 5998's before that date. And the very first 5998's were in fact, WE 421A. It's not clear when WE and Chatham worked out an arrangement allowing Chatham to manufacture the 5998. The earliest 5998s I have are dated 1957, week 10 (7-10). If anyone has older ones, please let me know.

Where do the 6520 tubes with domino plates fit in?