UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

cathoderay57 · 25th Jan 2019, 10:29 am

Hi, it doesn't matter what wire you use for such a tiny length. It is carrying less than 100mA. So long as the thickness of wire looks approx the same as the stub end of transformer wire you will be OK. Be careful when you solder the extension wire to the stub end because the transformer wire might be enamelled so you might need to scrape the enamel off carefully to avoid breaking the wire again so that it will take solder. As the speaker worked on an external amplifier it sounds like it isn't an energised type which requires high voltage on the energizing coil to magnetise the speaker pole piece. Presumably then there are only 2 wires to the speaker? I haven't checked the service sheet.

Cheers, Jerry

25th Jan 2019, 10:29 am	#9
cathoderay57 Nonode Join Date: Oct 2017 Location: Bristol, UK. Posts: 2,388	Re: Ultra Model 50 (1937) Restoration Hi, it doesn't matter what wire you use for such a tiny length. It is carrying less than 100mA. So long as the thickness of wire looks approx the same as the stub end of transformer wire you will be OK. Be careful when you solder the extension wire to the stub end because the transformer wire might be enamelled so you might need to scrape the enamel off carefully to avoid breaking the wire again so that it will take solder. As the speaker worked on an external amplifier it sounds like it isn't an energised type which requires high voltage on the energizing coil to magnetise the speaker pole piece. Presumably then there are only 2 wires to the speaker? I haven't checked the service sheet. Cheers, Jerry