[JTbbb]

Chatham 5998’s, clear top, bottom getters. I believe 1957.

 

[gibosi]

Hi All: I am a relative newbie to this forum and have a question about T-S 5998/421A tubes. If the tube is marked as a 5998/421A tube, which one is it: 5998 or 421A? Or is it a unique version of this tube? It seems as though most, if not all, of these tubes are dual-bottom getter tubes with clear tops like all of the 421A and some of the older 5998s. I apologize if this has been answered in the past but haven't gotten through all 521 pages so far. Thank you.

My current thinking......

All Western Electric 421A are also 5998. In 1950, WE formally requested that the RTMA (Radio-Television Manufacturer's Association) assign a special purpose number (5998) to the 421A. And in the early 1950's both numbers are commonly found on the WE 421A. It appears that later, as part of an agreement with Chatham, only Chatham used that designation.

Again it is my understanding that shortly after WE obtained the 5998 number, Chatham entered into an agreement with WE to produce a "5998". This involved purchasing the "guts" of the 421A from WE and installing them into a Chatham bottle, and also, licensing the 5998 designation.

In the end, there are no special versions of the WE 421A. But of course, given that the tube was manufactured for 30 some years, changes were made as a result of new materials and processes, as well as feed-back from the field. So a 421A manufactured in 1950 will likely sound somewhat different than one manufactured in 1980.

And a Chatham 5998 and a WE 421A, manufactured at about the same time will likely sound very similar. My advice: you can't go wrong with either.

But again, this is just a WAG on my part to try to understand these two tubes and the relationship between these two companies.

 

[leftside]

@leftside, so if I am to understand correctly, the above tubes labeled as WE421A break both rules of distinguishing the 5998 from 421A, having top getters and what appears to be non-coiled cathode heater wiring. Therefore, it is most likely a 5998 labeled as a 421A? It seems as though there are almost always labelling or re-labelling differences that go against accepted convention.

Yes I think so.

We also had fun over on the 6J5/L63 thread with some "GEC" labelled tubes that were actually Mullards and a few other rebranding examples.

 

[Dogmatrix]

A pair of plain old RCA 6as7g doing their thing in my new McChanson

 

[rlawry]

Thank you to all on the WE 421A/T-S 5998. I always learn something about tubes on this forum.

 

[JTbbb]

My current thinking......

All Western Electric 421A are also 5998. In 1950, WE formally requested that the RTMA (Radio-Television Manufacturer's Association) assign a special purpose number (5998) to the 421A. And in the early 1950's both numbers are commonly found on the WE 421A. It appears that later, as part of an agreement with Chatham, only Chatham used that designation.

Again it is my understanding that shortly after WE obtained the 5998 number, Chatham entered into an agreement with WE to produce a "5998". This involved purchasing the "guts" of the 421A from WE and installing them into a Chatham bottle, and also, licensing the 5998 designation.

In the end, there are no special versions of the WE 421A. But of course, given that the tube was manufactured for 30 some years, changes were made as a result of new materials and processes, as well as feed-back from the field. So a 421A manufactured in 1950 will likely sound somewhat different than one manufactured in 1980.

And a Chatham 5998 and a WE 421A, manufactured at about the same time will likely sound very similar. My advice: you can't go wrong with either.

But again, this is just a WAG on my part to try to understand these two tubes and the relationship between these two companies.

gibosi, I think you have pretty much hit the nail on the head. I know the photos of my Chatham’s could be a little better, but the internals look identical to those of a similar age WE421a posted a few pages back.

 

[tintinsnowydog]

Got a Chatham 6080WA thinking that it will be same as my Tungsol 6080 but it is quite different to the Tungsol. No extra mica supports and the top end looks quite different. Is it a Raytheon 6080 variant?

The two round (non-serrated) top micas along with the grey heater shields look like RCA 6080s to me. That is interesting, have never seen Chatham branding on any 6080 apart from the TS 3 mica support type.

 

[tubebuyer2020]

A pair of plain old RCA 6as7g doing their thing in my new McChanson

RCA 6as7g (even grey-plate) is now officially a fancy premium tube on par with 6080 Tung-Sol, anyone who disagrees - PM links to cheap NOS please!

PS: $30+ is not cheap imho.

 

[gibosi]

RCA 6as7g (even grey-plate) is now officially a fancy premium tube on par with 6080 Tung-Sol, anyone who disagrees - PM links to cheap NOS please!

PS: $30+ is not cheap imho.

With all due respect, if anything over $30 is too much, then I would recommend Svetlana 6N5S / 6N13S. They are quite good and fit into your budget.

 

[tubebuyer2020]

With all due respect, if anything over $30 is too much, then I would recommend Svetlana 6N5S / 6N13S. They are quite good and fit into your budget.

Both are within my budget, thank you very much, my point is that RCA 6as7g is not a cheap and common tube anymore. Open ebay and they are far and few in between. A couple of insane sellers are even asking for $100 bucks!

Example of cheap and somewhat comparable tubes: 6080 RCA/GE. They are undesirable of course, but it's not like they are Shuguang, Bottlehead consider them good enough.

 

[gibosi]

Both are within my budget, thank you very much, my point is that RCA 6as7g is not a cheap and common tube anymore. Open ebay and they are far and few in between. A couple of insane sellers are even asking for $100 bucks!

Example of cheap and somewhat comparable tubes: 6080 RCA/GE. They are undesirable of course, but it's not like they are Shuguang, Bottlehead consider them good enough.

I hear you. It seems that Covid has impacted tube prices. Just 15 months ago, many tubes were much more reasonable.

 

[tubebuyer2020]

I hear you. It seems that Covid has impacted tube prices. Just 15 months ago, many tubes were much more reasonable.

Pre-Covid I was only interested in portable gear! Also I think (Mass)Drop has boosted awareness of good headphone-centric audio I think, including tube amps.

 

[tintinsnowydog]

RCA 6080 and the 6AS7 are really great tubes, relatively plentiful and affordable still. I neglected them for a while but have really enjoyed using them recently. They match really well in tone with brighter headphones by warming up the bass response and smoothing out the highs e.g. with HD800.

 

[HTSkywalker]

RCA 6080 and the 6AS7 are really great tubes, relatively plentiful and affordable still. I neglected them for a while but have really enjoyed using them recently. They match really well in tone with brighter headphones by warming up the bass response and smoothing out the highs e.g. with HD800.

In general RCAs are polite all round performers but nothing outside the ordinary

 

[HTSkywalker]

RCA 6as7g (even grey-plate) is now officially a fancy premium tube on par with 6080 Tung-Sol, anyone who disagrees - PM links to cheap NOS please!

PS: $30+ is not cheap imho.

Good tubes for the price but not fancy ones, The Tung Sol 5998 is a fancy one