Like an octal but not an octal... - UK Vintage Radio Repair and Restoration Discussion Forum

daviddeakin · 20th Nov 2015, 9:04 am

Can someone remind me of the type of socket that looks almost like an octal, but doesn't actually fit an octal? I think the pins get slight closer together as you approach the centre of the row...

David G4EBT · 20th Nov 2015, 9:29 am

Mazda Octal? ('M.O'. rather than 'I.O' - International Octal).

A chart of valve bases attached. Though it states 'Valve Bases in Use Today' I've no idea when 'today' was, but decades ago in any event!

Hope that helps.

Radio Wrangler · 20th Nov 2015, 10:19 am

It was a rather nasty ploy to stop other makes of valve getting fitted to sets whose manufacturers had been hooked with favourable pricing or were part of an empire.

David

Sideband · 20th Nov 2015, 10:37 am

Quote:

Originally Posted by daviddeakin

Can someone remind me of the type of socket that looks almost like an octal, but doesn't actually fit an octal? I think the pins get slight closer together as you approach the centre of the row...

...and I think the central locating spigot was thicker and didn't fit the proper octal socket.

'LIVEWIRE?' · 20th Nov 2015, 10:41 am

Wouldn't be a Mazda Octal by any chance, would it? IIRC, they were different to the IO (International Octal) I have an old valve data book somewhere, but can't find it!!

Wendymott · 20th Nov 2015, 11:18 am

Yeah deffo Mazda Octal... Very annoying.

daviddeakin · 20th Nov 2015, 11:59 am

Mazda octal- yep that looks like that one, thanks!

Peter.N. · 20th Nov 2015, 1:09 pm

I think the gap between pins 1 and 8 is larger. SP41,61 etc.

G6Tanuki · 20th Nov 2015, 7:33 pm

Mazda Octals were 'intriguing' - apart from their obvious use in blocking the use of 'off-brand' valves as replacements, they did at least get right the putting of the heaters on pins 1 and 8 (so closer together and reducing the hum-issue which was - allegedly - a problem with the default 2-and-7 heater assignment for conventional octals)

What perplexes me is that the UK Military embraced the Mazda Octal for the likes of the 18/38-sets - surely they would have been in a position to force suppliers to standardize on 'proper' Octals to simplify supplies?

Mazda [along with Mullard/Philips] tried the same game a decade later with their "B8A" range as an attempt to block the B7G / B9A "standard" from being adopted by UK radio manufacturers.

daviddeakin · 25th Nov 2015, 2:41 pm

Quote:

Originally Posted by G6Tanuki

What perplexes me is that the UK Military embraced the Mazda Octal for the likes of the 18/38-sets - surely they would have been in a position to force suppliers to standardize on 'proper' Octals to simplify supplies?

I didn't know that. It's especially odd considering the efforts they went to to standardise other things bteween the US and Europe, like screw threads.

AC/HL · 25th Nov 2015, 4:25 pm

It would probably have been seen as interfering with Commercial interests, but there is the matter of dual sourcing, something they do generally pursue.

G6Tanuki · 25th Nov 2015, 5:56 pm

Yes, from the 4-letter markings on some of the ARP12/CV1331 I have here they were definitely not the sole-manufacture of Mazda!

Of the two that fall easily to hand = KB/EN suggests Thorn-AEI Sunderland, KB/D suggests Mullard, Mitcham.

The third is just

"B [Broad Arrow]
ZA7023
ARP12"

but is in the same-shape bottle as the KB/EN one.

If "B" can be taken to be part of the usual "sequence" then it's an Ediswan product.

20th Nov 2015, 9:04 am	#1
daviddeakin Hexode Join Date: Apr 2007 Location: W Yorks, UK. Posts: 407	Like an octal but not an octal... Can someone remind me of the type of socket that looks almost like an octal, but doesn't actually fit an octal? I think the pins get slight closer together as you approach the centre of the row...

20th Nov 2015, 9:29 am	#2
David G4EBT Dekatron Join Date: Feb 2003 Location: Cottingham, East Yorkshire, UK. Posts: 5,761	Re: Like an octal but not an octal... Mazda Octal? ('M.O'. rather than 'I.O' - International Octal). A chart of valve bases attached. Though it states 'Valve Bases in Use Today' I've no idea when 'today' was, but decades ago in any event! Hope that helps. Attached Thumbnails __________________ David. BVWS Member. G-QRP Club member 1339.

20th Nov 2015, 10:19 am	#3
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,873	Re: Like an octal but not an octal... It was a rather nasty ploy to stop other makes of valve getting fitted to sets whose manufacturers had been hooked with favourable pricing or were part of an empire. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

20th Nov 2015, 10:41 am	#5
'LIVEWIRE?' Rest in Peace Join Date: Mar 2006 Location: N.W. Oxfordshire(Chipping Norton) Posts: 7,306	Re: Like an octal but not an octal... Wouldn't be a Mazda Octal by any chance, would it? IIRC, they were different to the IO (International Octal) I have an old valve data book somewhere, but can't find it!!

20th Nov 2015, 11:18 am	#6
Wendymott Octode Join Date: Jun 2013 Location: Huddersfield, West Yorkshire, UK. Posts: 1,795	Re: Like an octal but not an octal... Yeah deffo Mazda Octal... Very annoying. __________________ Should get out more. Regards Wendy G8BZY

20th Nov 2015, 11:59 am	#7
daviddeakin Hexode Join Date: Apr 2007 Location: W Yorks, UK. Posts: 407	Re: Like an octal but not an octal... Mazda octal- yep that looks like that one, thanks!

20th Nov 2015, 1:09 pm	#8
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Like an octal but not an octal... I think the gap between pins 1 and 8 is larger. SP41,61 etc.

20th Nov 2015, 7:33 pm	#9
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Like an octal but not an octal... Mazda Octals were 'intriguing' - apart from their obvious use in blocking the use of 'off-brand' valves as replacements, they did at least get right the putting of the heaters on pins 1 and 8 (so closer together and reducing the hum-issue which was - allegedly - a problem with the default 2-and-7 heater assignment for conventional octals) What perplexes me is that the UK Military embraced the Mazda Octal for the likes of the 18/38-sets - surely they would have been in a position to force suppliers to standardize on 'proper' Octals to simplify supplies? Mazda [along with Mullard/Philips] tried the same game a decade later with their "B8A" range as an attempt to block the B7G / B9A "standard" from being adopted by UK radio manufacturers.

25th Nov 2015, 4:25 pm	#11
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Like an octal but not an octal... It would probably have been seen as interfering with Commercial interests, but there is the matter of dual sourcing, something they do generally pursue.

25th Nov 2015, 5:56 pm	#12
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Like an octal but not an octal... Yes, from the 4-letter markings on some of the ARP12/CV1331 I have here they were definitely not the sole-manufacture of Mazda! Of the two that fall easily to hand = KB/EN suggests Thorn-AEI Sunderland, KB/D suggests Mullard, Mitcham. The third is just "B [Broad Arrow] ZA7023 ARP12" but is in the same-shape bottle as the KB/EN one. If "B" can be taken to be part of the usual "sequence" then it's an Ediswan product.