6BW6 brands
 

Are there know differences in the performance of different brands/makes of 6BW6 values? The make I can read on most of mine are BRIMAR, but I can't see a manufacturer on some. Presumably they were made in different factories.

I've got a pair in a Codar AT5, one for the PA and one for the modulator. They are pushed quite hard, but within their limit. But I've noticed a significant difference in RF output and modulation linearity. Some examples are barely adequate and some really quite good. The biggest difference is when they are used in the modulator.

They all give approximately the same readings on an T160 valve tester.

Thanks.

Ian

Re: 6BW6 brands
 

Almost all the ones I've seen were Brimar though I do recall a few 'Pinnacle' ones showing up in later years.

The 6BW6 is a hard worker but if you mistreat them they can have a short and unhappy life. I generally found 6BW6 to stand mistreatment better than that other favourite the EL/UL84.

Re: 6BW6 brands
 

I have a few Philips branded, I also have some "un named" ones that I strongly suspect are Brimar, and I have several differentbox styles for the Brimar stock that I have. I have never used them in radio though, always in amplifiers, both guitar and hi-fi, never noticed or measured very much difference in any of them. They certainly have a long life!!

Joe

Re: 6BW6 brands
 

I'm pretty sure the 6BW6 was a Brimar design. The code sounds American but actually isn't. Why they didn't make the pinout the same as the EL84 is anybody's guess.

Re: 6BW6 brands
 

Yes, the 6BW6 was a Brimar original, registered in 1950 April.

Brimar appeared to use American registered designations for its own-design domestic receiving valves that were intended to complement its core American-origin range. Another example was the 12AH8 triode-heptode.

On the other hand, it had its own designation system that seemed to be used for valves that had industrial (perhaps as well as domestic) applications. Its version of the Osram Z77 was initially known as the 8D3. In this case Cossor undertook the American registration as the 6AM6, and later Brimar used this designation rather than 8D3. Brimar’s own designation system persisted into the 1960s, for example with the 13D7 super-high mu double triode.

Then Brimar also started using the Pro-Electron system, in the early 1950s, I think. Initially this was as a duplicate designation, e.g. 9U8/PCF82, then there were later issues with only a Pro-Electron designation. Perhaps that was grudging recognition that the Pro-Electron system was the best of the lot, providing more at-a-glance information about a valve than any of the others without the need for much prior rote-learning knowledge.


Cheers,

Re: 6BW6 brands
 

I have often read that the 6BW6 is a 6V6 in a smaller envelope. I prefer the 5763 for RF applications, but the 6BW6 is probably more versatile and less expensive.

Cheers

Aub

Re: 6BW6 brands
 

That’s my understanding. Already available was the 6AQ5, a 6V6 in B7G form, albeit with reduced maximum voltages. Presumably Brimar’s customers wanted – or Brimar thought they would want – a noval-based version of the 6V6 without any derating.

That seemed not to be needed in the USA at the time, although a few years later RCA added the noval-based 12AB5 variant of the 6V6 family for car radio applications.


Cheers,