Help identifying 1920s 1930s battery set

[mike1 ryan1]

Hi,
I've had an old battery set from the 30s I guess for a while now and recently decided to try and find out what exactly it is. I've searched the internet and looked through images trying to find it but can't. So I was wondering if any of you good people on here have any idea what it is, and more importantly how to hook up the various batteries needed to get it to work. Any information would be great thanks.
Mike

[Ed_Dinning]

It looks like many kit sets of the era; thousands were built in that time.
The coils look like Telsen devices, so it may be one of the many designs that were published in the Telsen Radiomag of this era.

Usually a good set to work on. It will need a 2V accumulator for the valve heaters;an HT battery (with tappings)of 120v max (120 for audio OP, 90v main HT and possibly 63.5 v for the SG. A grid bias battery of 4.5v or more is needed to provide neg bias to some valves.
NOTE DO NOT OPERATE THE SET WITH THE GB DISCONNECTED, OR EVEN CHANGE GB TAPS. THIS WILL DAMAGE COMPONENTS< VALVES ETC.

Faults are likely to be mechanical in nature (poor connections/ soldered joints). There is the possibility that the intervalve transformer will have one or more windings open circuit, but it can easily be rewound; you may get lucky and manage to by one (3:1 is the common ratio)

Ed

[mike1 ryan1]

Thanks for your reply that's most helpful info. What kind of speaker would work with these sets, I believe they were very high impedance devices, would it be a case of a modern speaker with a matching transformer, or could you use headphones I have some from this era.

[mike1 ryan1]

Does anyone have any info on the telsen coils suggested circuits. They are colvern ltd coils on this but I believe they are very similar. Tried searching the internet but not really finding anything.

[AC/HL]

You can use headphones, they'll be live (a nip rather than dangerous) and should be connected the right way round to aid what magnetism is left, rather than oppose it.
It's in good condition, many have suffered decades of lofts or worse. The screen grid valve looks to have lost some of it's getter, but may still be OK. There is a lot of information on the internet, and there were relatively few variations on circuitry, so it should be possible to restore it to health. Surprisingly for a near 100 year old radio spares are easier to obtain than many modern ones.

[Mike. Watterson]

Same may apply to ICs and any record player stylus! New steel needles still sold (which are usually intended for single use, but is that one or both sides?).
Transformers are the tricky parts, but I've used mains transformers of suitable ratio for interstage on 1929 to 1939 sets and for output on battery or mains. For Mains single ended you either need to loosen the I off E on core or a slightly larger rating so it doesn't saturate. The DC cancels on push-pull outputs.
Rewinding is possible and only solution for the earphones, horns and moving iron paper cone speakers.

[Ed_Dinning]

Hi, for the output use a normal single ended transformer from a typical mains or battery set (30:1 or similar should be OK, but almost anything will do). If from a single ended op stage it will be air-gapped so should be OK. Use a normal 3R speaker.

Telsen and Colvern made very similar speakers and connection details are online. If no success mail me in 2 weeks when I will have access to my archive.

Most of these coils had an aerial winding, possibly switched for LW. The Grid winding may also have been switched as well and there may or may not have been a 3rd winding for reaction. The reaction winding was not always fitted so a cheaper coil could be made. It can be left open circuit if not required.

Ed

[greenstar]

MIke, in case you do not know, there is the invaluable American Radio History website https://www.americanradiohistory.com/index.htm#T_ that has downloadable copies of many UK early radio magazines (and a shedload of other material). Most are searchable and there is a meta search for early magazines. https://www.americanradiohistory.com...dio/search.cgi

UK published magazines there that may include your set:
Modern Wireless
Popular Wireless
Amateur Wireless
Wireless Constructor
Wireless Magazine
Wireless Weekly
and of course Wireless World and possibly but might be a little late, Practical Wireless.
The Telson Magazine is also there, but at 1933 also looks a bit late for your set.

[PJL]

The anode current of a PM252 is enough to damage high impedance headphones. The Pye transformer would probably have been the anode load for the PM252 allowing the high impedance speaker to be capacitor coupled.

[mike1 ryan1]

Brilliant thanks lots of info and I'll have a look at the American site tonight at work. I'm just going to clean up and check all the connections, I've a fairly good idea where all the connections to the batteries should go and speaker, aerial etc.
Thanks again will be nice to hear it working again.
Mike

[mike1 ryan1]

Here is a couple of pics of a speaker I bought from the same auction. Does this look like the kind of thing a set like this would use. Again I can't seem to find anything about this particular model of speaker. Typed the details into a search and trauled Google images but didn't find anything.
Thanks,
Mike

[PJL]

Difficult to work out the size from the picture but that looks as though it came from a large speaker enclosure but a similar one was used in the Philips 2601.

You may struggle to get it to work as it will probably need a DC supply for an energising coil. Are there any markings on the controls on the back?

[mike1 ryan1]

Not that I can see no, unless I can get some info and a wiring diagram I'll just leave it alone for now.
Mike

[Ed_Dinning]

Hi , it looks as if it is from a mains set. Battery sets, unless DC mains types did not normally have energised speakers, and not normally that big.

Ed