Set identification needed - UK Vintage Radio Repair and Restoration Discussion Forum

AndyWright · 11th Nov 2021, 4:49 pm

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

turretslug · 11th Nov 2021, 5:17 pm

The bezel and knobs look like EMI pre-war types- maybe a professional-market packaging of one of their "all-wave" or "export" sets?

AndyWright · 11th Nov 2021, 5:34 pm

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.

AndyWright · 11th Nov 2021, 5:48 pm

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photographs from the 2018 thread I can see I have the same set as the OP in that thread as one of the electrolytics has been replaced by a smaller component.

Ed_Dinning · 11th Nov 2021, 8:41 pm

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

AndyWright · 12th Nov 2021, 8:15 am

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

Ed_Dinning · 12th Nov 2021, 8:45 pm

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

AndyWright · 14th Nov 2021, 3:31 pm

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

Ed_Dinning · 14th Nov 2021, 9:06 pm

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

AndyWright · 15th Nov 2021, 6:36 pm

Amazingly it works! The valve rectifier had to be replaced, but it provides a reasonable volume into a 600 ohm loudspeaker.

11th Nov 2021, 4:49 pm	#1
AndyWright Tetrode Join Date: Feb 2012 Location: Bishop Auckland, County Durham, UK. Posts: 92	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 Attached Thumbnails

11th Nov 2021, 5:17 pm	#2
turretslug Dekatron Join Date: Nov 2011 Location: Surrey, UK. Posts: 4,395	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?

11th Nov 2021, 5:34 pm	#3
AndyWright Tetrode Join Date: Feb 2012 Location: Bishop Auckland, County Durham, UK. Posts: 92	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.

11th Nov 2021, 5:48 pm	#4
AndyWright Tetrode Join Date: Feb 2012 Location: Bishop Auckland, County Durham, UK. Posts: 92	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.

11th Nov 2021, 8:41 pm	#5
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	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
AndyWright Tetrode Join Date: Feb 2012 Location: Bishop Auckland, County Durham, UK. Posts: 92	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
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	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
AndyWright Tetrode Join Date: Feb 2012 Location: Bishop Auckland, County Durham, UK. Posts: 92	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
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	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
AndyWright Tetrode Join Date: Feb 2012 Location: Bishop Auckland, County Durham, UK. Posts: 92	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.