[JKDJedi]

To my limited knowledge the 421a was made by western electric, and has small Differences from the 5998.

The Western Electric 421A appears to be a juiced-up 5998 built especially for WE by TS/Chatham. One major difference is the WE has a transconductance figure of 20,000 micromohs, 1.5 times that of the 5998, at 14,000 micromohs. The amplificatino factor is also a bit higher than the 5998, 6.1 compared to 5.5.

 

[JKDJedi]

I have the 421a and yeah ...it's special, kinda saving it for my retirement enjoyment. Reason I'd like to pick up a 5998, wouldnt feel bad burning out a 5998...

 

[bcowen]

The Western Electric 421A appears to be a juiced-up 5998 built especially for WE by TS/Chatham. One major difference is the WE has a transconductance figure of 20,000 micromohs, 1.5 times that of the 5998, at 14,000 micromohs. The amplificatino factor is also a bit higher than the 5998, 6.1 compared to 5.5.

The WE was actually made by TS? Far out. I had no idea WE had ANY tubes OEM'd for them....thought it was always the other way around. Thanks for that info!

 

[JKDJedi]

The WE was actually made by TS? Far out. I had no idea WE had ANY tubes OEM'd for them....thought it was always the other way around. Thanks for that info!

Well in theory, there's Tung Sol 421a out there too, and an on going debate on the origins of the Western Electric 421a. It looks and smells a lot of the 5998.. which is made by Tung Sol..

 

[cddc]

The 421A was a designation exclusive to Western Electric, wasn't it?

I agree with Jedi.

WE 421A was made by Tung Sol, most people seem to agree with this assessment, because WE421A looks exactly the same as Tung Sol 421A and and some Tung Sol 5998.

The only point up to debate is wether WE 421A is actually the same as TS 5998. WE 421A is a cherry-picked TS 5998, most people seem to support this from what I read. It seems WE designed the 5998/421A tube, and TS manufactured these tubes using WE's patents. When TS manufactured the tubes, the ones with better potential and can have higher transconductance would be labeled as WE 421A and shipped to WE. The rest were labeled as either TS 421A or TS/Chatham 5998.

 

[DenverW]

I wish I had my 5998 to do an exact comparison, but I believe there are some slight differences, such as with the lower construction. There are definitely some data sheet differences.

 

[cddc]

The Western Electric 421A appears to be a juiced-up 5998 built especially for WE by TS/Chatham. One major difference is the WE has a transconductance figure of 20,000 micromohs, 1.5 times that of the 5998, at 14,000 micromohs. The amplificatino factor is also a bit higher than the 5998, 6.1 compared to 5.5.

That's true.

The transconductances of WE 421A and TS 5998 are different. However, I read that it was caused by using different plate voltages. With higher plate voltage, you'll get higher measured transconductance. Some people argued that if applying the same measuring parameters, they would get the same transconductance from 5998. Not sure if it's true though...I am not electrical engineering.

 

[bcowen]

I agree with Jedi.

WE 421A was made by Tung Sol, most people seem to agree with this assessment, because WE421A looks exactly the same as Tung Sol 421A and and some Tung Sol 5998.

The only point up to debate is wether WE 421A is actually the same as TS 5998. WE 421A is a cherry-picked TS 5998, most people seem to support this from what I read. It seems WE designed the 5998/421A tube, and TS manufactured these tubes using WE's patents. When TS manufactured the tubes, the ones with better potential and can have higher transconductance would be labeled as WE 421A and shipped to WE. The rest were labeled as either TS 421A or TS/Chatham 5998.

Interesting. I'm a total newbie with this tube type so have lots to learn. Thanks for the additional info!

 

[JKDJedi]

Here's a 7236 worthy of a collection,and priced to sell. Seen this one listed elsewhere for $95. Sounds great with a tall d getter Tung Sol 6SN7GTB. Currently paired with a Foton .. (My Tung Sol 7236 has some left channel static, gonna blast the pins with a sodder gun to see if that can help) Kinda tempted to grab the Cetron.

https://www.ebay.com/itm/VINTAGE-SY...451056?hash=item443a832bb0:g:bOMAAOSwqu5anCuW

 

[bcowen]

Here's a 7236 worthy of a collection,and priced to sell. Seen this one listed elsewhere for $95. Sounds great with a tall d getter Tung Sol 6SN7GTB. Currently paired with a Foton .. (My Tung Sol 7236 has some left channel static, gonna blast the pins with a sodder gun to see if that can help) Kinda tempted to grab the Cetron.

https://www.ebay.com/itm/VINTAGE-SY...451056?hash=item443a832bb0:g:bOMAAOSwqu5anCuW

Speaking of Fotons, this just came in today. Advertised as a pair of '58's, I got this nice rib plate and a '57 smooth plate instead. Sometimes even I get lucky.

 

[JKDJedi]

Speaking of Fotons, this just came in today. Advertised as a pair of '58's, I got this nice rib plate and a '57 smooth plate instead. Sometimes even I get lucky.

I think you were the one that got me interested in theses little power houses, and about that Sylvania.... meh, got the Tung Sol going again, what a difference zapping the pins can make. Crackling gone,

 

[bcowen]

I think you were the one that got me interested in theses little power houses, and about that Sylvania.... meh, got the Tung Sol going again, what a difference zapping the pins can make. Crackling gone,

Nice pic!! What year is that Foton? Have a '52 in my Lyr 3 right now...with resoldered pins of course. That and the Frankie 7N7 are the two most regular tubes in my rotation. The 7N7 easily bests the Foton at the soundstage and imaging thing, but when I'm in a rock/blues/metal mood the Foton gets my foot tapping like no other.

 

[bcowen]

I think you were the one that got me interested in theses little power houses, and about that Sylvania.... meh, got the Tung Sol going again, what a difference zapping the pins can make. Crackling gone,

Ever try one of these? Not sure who all might have made this particular type. Other than the Matsu 7DJ8 (not an uber-tube but pretty good for the money) I've not heard a Japanese-made tube that got me excited. But you never know where a diamond in the rough may lurk...

 

[cddc]

Never heard a J-tube in the 6AS7G family, but it looks like an RCA 6AS7G to me.

Not sure if it's a rebranded RCA, or manufactured according to RCA's design.

If it sounds like an RCA, I will stay away

 

[JKDJedi]