Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

http://www.r-type.org/exhib/abc0004.htm

That is mid period production. The early ones had a metal skirt on the base like Loctals and the last ones looked like B9A Novals but with a locating pip on the side. Mazda produced some with a central metal spigot on the metal skirt: https://commons.wikimedia.org/wiki/F...da_Rimlock.JPG

They were largely restricted to the UK and Europe, but were the dominant standard there in the first half of the 50s.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

Rimlock B8A valve bases, photos of the earlier metal base and the later all glass.
http://www.tubedata.org/bases/Rimlock_6F15_P1040363.jpg

http://www.tubedata.org/bases/Rimlock_EL41.jpg
http://www.tubedata.org/bases/Rimlock_UAF42.jpg

Crossed post

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

Thanks gentlemen, I have seen the type in the first pic ( UL41) but I would just call that a standard noval, BUT specifically Philips because they were the only ones to use that "glued on base" look. I have never seen the type that looks like a loctal, with or without spigot.

Thanks again

Joe

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

We tend to use the designations B8A and B9A, which better highlights the different pin count. As said, this was a European standard so you would only have seen it on imported sets.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

B9A Novals have 9 pins with a gap for orientation. B8A Rimlocks have 8 equally spaced pins with a side pip for orientation. They are approximately the same size, and as I said above, late production Rimlocks were made without the metal or glass collar at the bottom and look very like a Noval with a side pip.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

This 1946 article by Philips provides background on the inception of the Rimlock (B8A) type valve. Philips acknowledged the existence of the American miniature (B7G) type, and explained why a larger envelope with more pins was required.

Attachment 189257

Philips’ view on the similarities between the Rimlock and noval (B9A) types comes out in this 1949 item on the EQ80 enneode.

Attachment 189258

The early history of the American B7G valve is provided in this 1947 RCA article, at the end of which is mentioned, in a matter-of-fact way, RCA’s apparent first noval release, the 12AU7.

Attachment 189259


Cheers,

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

As mentioned upthread, some of the Rimlocks received American registrations and designations in 1955. Included were the following, all with 1955 October 10 dates:

EF41 as 6CJ5
ECH42 as 6CU7
EBC41 as 6CV7
EAF42 as 6CT7
EK41 as 6CK5
UF41 as 12AC5

On its face, that is puzzling, as by late 1955, Philips had completed its noval radio series, late issues being the EF89 and EBF89, and had released in Europe the EBC81, previously held back from that market. So by then the Rimlocks were no longer “front line” valves.

One possible explanation is that this was done to provide designations that better suited the Australian market, where although Rimlocks were apparently never manufactured nor used in Australian-made equipment, nonetheless they were imported to provide spares for imported equipment that was fitted with Rimlock valves. Here is a 1954 Australian advertisement for Eddystone receivers that does mention the (Rimlock) valves used therein.

Attachment 189260

I don’t recall whether the Rimlocks sold in NZ in the 1960s showed both the original and the American designations. Probably so, as quite a few valves did have double designations, and NZ was essentially bilingual, as it were, when it came to valve designations.. But when Rimlocks were used as original equipment in NZ, as in the early versions of the famous Bell Colt radio receiver, it was with their original designations.


Cheers,

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

This has become a very educational thread for me at least.


EF41 as 6CJ5
ECH42 as 6CU7
EBC41 as 6CV7
EAF42 as 6CT7
EK41 as 6CK5
UF41 as 12AC5

For instance, I have NEVER seen any of the above valves in either designation. I did start my career as a kid pestering the local TV repairers to "can I see please".
I had two mentors that taught me a great deal of what I still remember ( yes, thats a hint to the education system). As I have mentioned before, RCA had a huge influence on Australian made valves, even though I "think" that the valve factories made batches for whoever was paying for them at the time.
Philips were in Adelaide, some thousands of kilometres from where I lived, but did make many valves for the TV market. MOSTLY though they were branded Mullard.
RCA, Radiotron and AWV were in Sydney a few hundred miles away, and that could also have a bearing on what I saw and learned.
The most common brand name in Australia was AWV. Amalgamated Wireless Valve.
If I am given a choice of valve for use, and I have a choice of brands, I will generally use the AWV branded units, as they were tough as old boots and lasted very well under the most severe circumstances. I have mentioned before working on AWA AM radio transmitters where the lowly old 807 would show quite bright pink plates for years without faltering. This is NOT a plug for aussie made BTW !!.

I was given a radio from a tank when I was young, and it had he first "bodgie" valves I had seen. They were loctals, and the radio was from South Africa.
That was as far afield as I had seen up to that point. I went away and built mainframe computers for quite a few years. When the early computer boom finished so had the valve era.
Octal based valves ( eight pins with a locating spigot) were extremely common, as were 5 pin (807 style). "Most" Australian radios that I saw/worked on used 7 pin miniature, or noval bases, and for the life of me, (and I have been thinking since this thread started)
TV's were almost all octal or noval, and audio varied. Some of the best audio equipment came from across the ditch ( New Zealand), but all the valves used American designations.

As far as this goes, and only slightly off topic, I have NEVER even seen an AC/DC radio in my life. There were a few early B/W TV sets that were, but I have never worked on one. I think this may have to do with Australian regulations, but I cant prove that. We do have an excellent record for electrical installation however.


Thanks again to all

Joe

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

There was a very substantial US military presence in the-then West Germany post-war and overseas allowance was good- could there have been a significant number of the quality table radios etc. offered by a number of German manufacturers and equipped largely or solely with Rimlock valves that came back to the US with their owners, subsequently resulting in a worthwhile US requirement for Rimlock spares? I had always assumed that this would have been a drop-in-the-ocean market but registering US designations for European valve types may have been part of trading red-tape even for small quantities.

Another thing that has long struck me about the Rimlock series of valves is that they seem to be outliers compared to their Mullard/Philips predecessors and successors in terms of their typically low heater-current requirements and relative socket complexity. Both of these are more typical of German-origin valves of the late '30s/early '40s and Rimlocks have a certain resemblance to larger Telefunken valves such as the LS50 power pentode with its 8 symmetrically-disposed pins in a glass button base and a keyed glass envelope. Could it be that Rimlocks represented technology-acquisition of a Telefunken-originated and wartime-development valve series that seemed too good to pass up?

Edit: I was slightly surprised to see an EK41 listed- that really would have been a nod towards US practice, away from the European triode-hexode/heptode trend- but cross-referencing 6CK5 suggests the more familiar EL41?

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

One thing I have noticed between B8A rimlock, and B9A noval (and B7G), the pins of B8A valves are hard and stiff, whereas the others aren't.

I can see the need for pins that bend, if the valve is knocked sideways in the valveholder then the pins bend rather than the glass breaks. And B8A valves are supported by the skirt anyway so the force is not taken by the pins. But given that bendy pins would not detract from the valve in B8A, and given that the alloy had already been developed for B7G, what did B8A have rigid pins? Or was it just cheaper?

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

Yes, that was a typo on my part - it should have been EL41, not EK41.

There was, though, a Rimlock octode frequency changer, namely the DK40. This was part of a range intended for use in battery-operated non-portable receivers. (Philips had also introduced a range of B7G miniatures for use in battery-operated portable receivers.)


Cheers,

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

I have taken this topic to a separate thread, "AC-DC Live Chassis Receivers in the Antipodes", at: https://www.vintage-radio.net/forum/...d.php?t=159413.


Cheers,

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

The design of the glass base and pins was likely based on the older B8G base, so developed before the B7G.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

Hi

I have just turned 80 yrs young and until recently I had never seen the "term" NOVAL until looking through the entries on this site, I have only ever known that range of valves as B9A, it just goes to show you that you are never to old to learn.

Unless of course there are NOVAL valves and B9A valves.

Bill

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

Here's one:

http://www.r-type.org/exhib/abc0004.htm

The socket has a thin metal skirt which surrounds and guides the larger diameter section of the envelope just above the pins.

Not too visible in the photos, there is a pip moulded into the glass on the lower left side. The shirt on the socket has a shaped slot to spring out and allow the pip past. The bottom of the slot ends in a circular hole to accept and retain the pip.

These valves could be devils to unplug after years and were too easily broken. Sometimes the skirt cracked the pip off and let air in.

As a kid, I hated the things. Any I acquired went straight in the bin.

I also didn't bother with Mazda Octal. This was a distorted version of International Octal. Deliberately incompatible to force set users to only buy one brand of replacement valves. Evil!

David

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

It's an American term originally. I tend to refer to 'B9A Novals' as lots of people don't know what one or the other means. Similarly I use 'B8A Rimlocks'.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

The earliest reference to the noval type that I have found is in AWV Radiotronics 1947 March, in connection with the RCA 12AU7:

Attachment 189668

Interestingly early advertising by RCA and GE in respect of their noval valves did not include the "noval" descriptor.

The noval name seemed to have crossed the Atlantic failry readily. Philips used it in 1949, which I think was the first year in which European-made novals became available:

Attachment 189669

And it was used by Wireless World in 1950 connection with the Mullard EF80 and ECL80:

Attachment 189670

Re "Innoval", it is looking very much as if this was exclusive to Philips Australia.


Cheers,

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

I think 'noval' actually fell out of use in Britain as the 50s progressed, and has only re-entered use in the last 20 years with the internationalisation of technical vocabulary.

I'd never heard of 'innoval' before encountering it in this thread.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

Neither did I.

In the Netherlands, noval was the most used designation, with magnoval and novar for the larger valves. I never remembered which letter went behind B9.

Re: Valve Items - Philips/Mullard Rimlock-to-Noval Transition
 

The Mazda Octal does have the merit that the spigot is large enough in diameter to house the exhaust tube, so the whole electrode structure can sit much lower down in the base. Capacitances and lead inductances are lower as well as the valve being more compact.

It's not as good as B8G though.