Radio id, possible kit constuction ? - UK Vintage Radio Repair and Restoration Discussion Forum

Freya · 25th Jun 2018, 1:18 pm

The only valves that can be identified are the Mullard PM2 and the Cossor point one. I only have the picture at the moment but hope to get the set soon.

Mr Moose · 25th Jun 2018, 7:29 pm

Hello.
It has a variety of different makes of components so is almost certainly a home built set either from a published design or freelance. It is probably about 1927.
It is unusual in that it uses resistance-capacity coupling rather than the more common transformer coupling between stages.
I think the first valve is a 'Cossor Point One RC' which appeared in 1927 with a high impedance for resistance-capacity coupling.
The second valve could be a Cosmos valve of which there are several possibilities such as this http://www.r-type.org/exhib/aaj0049.htm.
Yours, Richard

Freya · 26th Jun 2018, 9:13 am

Thanks for that info Richard, the earlier sets are new to me, having only worked on 30`s sets until now.

rontech · 26th Jun 2018, 9:28 am

The beautifully grained surface on which the old set stands makes me curious.

Is it by any chance the top of an impressive late 1930's console radio?

Herald1360 · 27th Jun 2018, 10:13 am

Dining room table?

Place mats, bowls etc.....

Freya · 28th Jun 2018, 4:06 pm

What type of speaker would I need to source or would it be headphones only. From what I gather reading some books, phones need to be about 2000 ohms ?

AC/HL · 28th Jun 2018, 7:59 pm

PM2 is a power (?) valve, so it would have been a high impedance speaker. Headphones would work, but are at HT potential. You'd need to add an output transformer for a modern speaker.

Freya · 28th Jun 2018, 9:20 pm

Thanks for that Bill.

PJL · 28th Jun 2018, 9:55 pm

Bit of an odd mix of valves. They may all be 2V filament but do check first, the Cossor will say on the label, the Cosmos you need to look for a mark.

ms660 · 30th Jun 2018, 6:45 pm

There's a PM2 valve data sheet here:

http://g3ynh.info/valves/old/Data-Bo...G/RVG-p011.pdf

Lawrence.

25th Jun 2018, 1:18 pm	#1
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,990	Radio id, possible kit constuction ? The only valves that can be identified are the Mullard PM2 and the Cossor point one. I only have the picture at the moment but hope to get the set soon. Attached Thumbnails __________________ Stephen _________"It`s only an old telly" ___

25th Jun 2018, 7:29 pm	#2
Mr Moose Octode Join Date: Jul 2008 Location: Gloucestershire, UK. Posts: 1,043	Re: Radio id, possible kit constuction ? Hello. It has a variety of different makes of components so is almost certainly a home built set either from a published design or freelance. It is probably about 1927. It is unusual in that it uses resistance-capacity coupling rather than the more common transformer coupling between stages. I think the first valve is a 'Cossor Point One RC' which appeared in 1927 with a high impedance for resistance-capacity coupling. The second valve could be a Cosmos valve of which there are several possibilities such as this http://www.r-type.org/exhib/aaj0049.htm. Yours, Richard

26th Jun 2018, 9:13 am	#3
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,990	Re: Radio id, possible kit constuction ? Thanks for that info Richard, the earlier sets are new to me, having only worked on 30`s sets until now. __________________ Stephen _________"It`s only an old telly" ___

26th Jun 2018, 9:28 am	#4
rontech Heptode Join Date: Jun 2017 Location: Southport, Merseyside, UK. Posts: 646	Re: Radio id, possible kit constuction ? The beautifully grained surface on which the old set stands makes me curious. Is it by any chance the top of an impressive late 1930's console radio?

27th Jun 2018, 10:13 am	#5
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Radio id, possible kit constuction ? Dining room table? Place mats, bowls etc..... __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

28th Jun 2018, 4:06 pm	#6
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,990	Re: Radio id, possible kit constuction ? What type of speaker would I need to source or would it be headphones only. From what I gather reading some books, phones need to be about 2000 ohms ? __________________ Stephen _________"It`s only an old telly" ___

28th Jun 2018, 7:59 pm	#7
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Radio id, possible kit constuction ? PM2 is a power (?) valve, so it would have been a high impedance speaker. Headphones would work, but are at HT potential. You'd need to add an output transformer for a modern speaker.

28th Jun 2018, 9:20 pm	#8
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,990	Re: Radio id, possible kit constuction ? Thanks for that Bill. __________________ Stephen _________"It`s only an old telly" ___

28th Jun 2018, 9:55 pm	#9
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Radio id, possible kit constuction ? Bit of an odd mix of valves. They may all be 2V filament but do check first, the Cossor will say on the label, the Cosmos you need to look for a mark.

30th Jun 2018, 6:45 pm	#10
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Radio id, possible kit constuction ? There's a PM2 valve data sheet here: http://g3ynh.info/valves/old/Data-Bo...G/RVG-p011.pdf Lawrence.