Speaker on Vintage Radio

[Johnnycosmos]

Hi,

I've a lovely old radio. It has been restored in that capacitors etc have been replaced and it works lovely. Piccies attached. I believe it was custom made in Bradford in around 1937 by my great Uncles brother who had a radio shop.
Kitten scratched speaker grill so just sourcing some new.
Made me wonder.
The kitten also managed to slightly tear the speaker cone/diaphragm.
If I fit a more modern speaker would that improve the sound? Is there such a thing as a speaker with a built in amp? Or should I just try and source a new cone?
I really don't know what I don't know.

Many thanks for your thoughts.

Kindest
John

[paulsherwin]

You can usually repair minor damage to speaker cones quite easily. You just need some thin paper and PVA adhesive.

Changing the speaker is possible but should be seen as a last resort. It won't be straightforward and won't improve the sound. More importantly, it will wreck the originality of what is now practically a museum piece.

[ms660]

Just to note that the loudspeaker appears to have a field coil.

Lawrence.

[dazzlevision]

I see the speaker says M R G Bradford. Mains Radio Gramophones (of Bradford) probably made the whole thing. MRG were taken over by Radio Rentals and were later renamed Baird Television - around 1960, when RR acquired the Baird name rights. The factory was eventually closed in the 1970s.

If I fit a more modern speaker would that improve the sound?

Probably not, modern 'speakers are designed for closed or vented cabinets, the old ones are for a more open box like yours. And as Paul said a thin bit of paper with a bit of PVA will execute a good repair, handy hint, tear the paper to size so the edges are tapered. An overlap of 3 or 4mm all round is all you need.

Any thin cloth will be fine, pick your own pattern, I find Indian cloth shops have a wide range of patterns and modern materials are kitty proof too. I have one near me in Southall and having me (a big biker type bloke) walk in raises many eyebrows among the exclusively female staff and visitors. I have asked for small pieces for speakers and always go away with a bit for nothing and a cup of tea too! There can be a bit of a language barrier but their English is infinity better than my Hindi. Laughter is universal.

[Herald1360]

That output valve pair looks distinctly "interesting"

[Station X]

Pee Exe Fours?

[Nickthedentist]

Yep, I bought the same chassis in a homemade cabinet from a charity shop a few years ago, and nobody could ID it. Now I know!

John. Keep the original speaker. It's part of its history and there's no modern speaker which will replace it.

[greenstar]

Nice discussion on speaker repair here:
https://antiqueradios.com/forums/vie...?f=10&t=343931

[Johnnycosmos]

Hi All,

Many thanks. Most helpful.
Chris? What is 'interesting'?

Kindest wishes

John

[Station X]

That question is best answered in a Private Message (PM).

[Vintage_RC]

I have had a lot of success repairing speaker cones with model aircraft tissue applied with diluted PVA. Even quite extensive damage can be repaired with patience and care.

[Glowing Bits!]

Originally Posted by Vintage_RC

I have had a lot of success repairing speaker cones with model aircraft tissue applied with diluted PVA. Even quite extensive damage can be repaired with patience and care.

Same here, one was fitted to an old GE American set, it crossed my mind to replace it but the mounting bracket is a part of the speaker itself.
Watered down PVA and kitchen paper/bog roll seems to work well, it can sometimes alter the sound but altering speaker TX primary capacitors can compensate for this.

[David G4EBT]

As Lawrence said in post No3, the speaker has a field coil (it states the coil resistance on the label), and hence, the speaker is mains energised. The coil magnetises the speaker, as well as acting as a smoothing choke in the HT supply. Replacing it with a modern permanent magnet one, as well as destroying the authenticity of the radio, would require either a choke in the HT supply, or converting the HT from an L/C smoothing circuit to R/C.

As regards repairing the cone, flexible glue such as UHU or Copydex is preferable to PVA, except perhaps for small tears. As to suitable paper, toilet tissue is best avoided as it’d designed to dissolve in water. (Drop a piece in a bowl of water and see what happens to it). Kitchen roll however, is formulated to not dissolve in water - leastways, not easily. I’ve used newspaper to good effect.

[Johnnycosmos]

Many thanks for really helpful advice. Much appreciated.
John