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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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11th Nov 2021, 4:49 pm | #1 |
Tetrode
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 92
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Set identification needed
Hello
does anyone have any idea what radio set this is? I obtained it at the Hornsea rally a few weeks ago, obviously a receiver, with 6 octal valves including rectifier, and designed for rack mounting. It looks like there was some kind of identification plate below the dial at some time. On the rear there is a GPO stamp. Cheers Andy G4OJY |
11th Nov 2021, 5:17 pm | #2 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,397
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Re: Set identification needed
The bezel and knobs look like EMI pre-war types- maybe a professional-market packaging of one of their "all-wave" or "export" sets?
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11th Nov 2021, 5:34 pm | #3 |
Tetrode
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 92
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Re: Set identification needed
I've just done some cleaning and found a small label inside. Apparently it's an EMI RR20. Just found a thread from 2018 on this forum.
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11th Nov 2021, 5:48 pm | #4 |
Tetrode
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 92
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Re: Set identification needed
Looking at the photographs from the 2018 thread I can see I have the same set as the OP in that thread as one of the electrolytics has been replaced by a smaller component.
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11th Nov 2021, 8:41 pm | #5 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,195
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Re: Set identification needed
Hi Andy, I did a set looking very much like that for a guy up in Northumberland a few years ago. It had been used as a ship's entertainment set and drove a small PA system.
The tuning knobs certainly look HMV/ EMI Ed |
12th Nov 2021, 8:15 am | #6 |
Tetrode
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 92
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Re: Set identification needed
Hello Ed
did you have any circuit info? Google searches draw a complete blank for this set, although its pretty simple I could probably get it going without a schematic. Cheers Andy |
12th Nov 2021, 8:45 pm | #7 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,195
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Re: Set identification needed
Hi Andy, no schematics I'm afraid, but as you say it was a simple circuit.
A recap , one resistor gone high and I think one valve with an OC heater Ed |
14th Nov 2021, 3:31 pm | #8 |
Tetrode
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 92
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Re: Set identification needed
Hello Ed
I've done the recap and changed the off value resistors. What impedance load did you connect to the output, and was there enough output to drive a loud speaker? I'm guessing it may want to drive 600 ohms? Cheers Andy |
14th Nov 2021, 9:06 pm | #9 |
Dekatron
Join Date: Jan 2004
Location: Newcastle upon Tyne, Tyne & Wear, UK.
Posts: 8,195
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Re: Set identification needed
Hi Andy, try a set of headphones that should be about right. Don't turn the wick up until you see how loud it is.
You may need a small transformer to operate a 3 ohm speaker as it may be 100v line for audio distribution ~ these transformers are readily available Ed |
15th Nov 2021, 6:36 pm | #10 |
Tetrode
Join Date: Feb 2012
Location: Bishop Auckland, County Durham, UK.
Posts: 92
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Re: Set identification needed
Amazingly it works! The valve rectifier had to be replaced, but it provides a reasonable volume into a 600 ohm loudspeaker.
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