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Audio and Video Talk
The Vintage Audio Section
Lafayette Superheterodyne Radio - 1935
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<blockquote data-quote="El Sid" data-source="post: 1005795" data-attributes="member: 18550"><p>Thanks all for the hints and suggestions. </p><p></p><p>I tested the transformer with all valves out, and it makes all the voltages required: 360-0-360, 2,5V and 5V. I then started tracing from there and came up with bad news. What I thought was the output transformer is actually the choke, and tracing the wires on the speaker plug pictured below, I realised that the output transformer was obviously mounted on the field coil speaker (not uncommon in old radios). So not only is there no speaker, there's also no OPT. I suppose one could use a permanent magnet speaker (although not sure how important the choke effect of the field coil is for the power supply), but where to find a push-pull OPT for a 47 valve? Not sure the owner's budget extends to having one wound. </p><p></p><p><img src="https://i.imgur.com/bWNfy50l.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="El Sid, post: 1005795, member: 18550"] Thanks all for the hints and suggestions. I tested the transformer with all valves out, and it makes all the voltages required: 360-0-360, 2,5V and 5V. I then started tracing from there and came up with bad news. What I thought was the output transformer is actually the choke, and tracing the wires on the speaker plug pictured below, I realised that the output transformer was obviously mounted on the field coil speaker (not uncommon in old radios). So not only is there no speaker, there's also no OPT. I suppose one could use a permanent magnet speaker (although not sure how important the choke effect of the field coil is for the power supply), but where to find a push-pull OPT for a 47 valve? Not sure the owner's budget extends to having one wound. [IMG]https://i.imgur.com/bWNfy50l.jpg[/IMG] [/QUOTE]
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Audio and Video Talk
The Vintage Audio Section
Lafayette Superheterodyne Radio - 1935
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