Rogers Ravensbrook Third Channel Connection - UK Vintage Radio Repair and Restoration Discussion Forum

MarkAT6 · 29th Jul 2021, 11:22 am

Hi All,

A quick query on the Rogers Ravensbrook Tuner Amplifier which I've been testing recently. In addition to the usual Left & Right speaker Din output connectors there is another Din connector which is labelled "Third Channel". Unfortunately I only have the Ravensbrook Amplifier schematic which doesn't appear to show this connector. I was therefore wondering whether this connection a simple Hafler style output for a rear 'ambience' speaker? I've plugged a 3rd speaker into the connector and audio does indeed emanate from it. Does anybody know what this connection is for and / or have the schematic for this tuner amplifier which shows this connection.

Regards

Mark

Radio Wrangler · 29th Jul 2021, 7:04 pm

Two guesses... it could be a mono output or it could be an output if an optional board is added to decode the auxiliary channel. Sometimes called SCA or 'storecast' The Zenith pilot tone stereo system was designed with a bit of spare capacity which in some countries is used to distribute mind-numbing muzak to shops.

David

tony brady · 29th Jul 2021, 9:29 pm

I think it's most likely a Hafler style output. easy to test with the power off as the '3rd' speaker would hang between the positive outputs of the left & right channels, sometimes with a low value resistor in series.

just do a continuity check from the positive pin of say the left channel and see if you have continuity to one of the connections on the 3rd din socket. do the same for the right channel

29th Jul 2021, 11:22 am	#1
MarkAT6 Tetrode Join Date: Jul 2011 Location: Worcestershire, UK. Posts: 87	Rogers Ravensbrook Third Channel Connection Hi All, A quick query on the Rogers Ravensbrook Tuner Amplifier which I've been testing recently. In addition to the usual Left & Right speaker Din output connectors there is another Din connector which is labelled "Third Channel". Unfortunately I only have the Ravensbrook Amplifier schematic which doesn't appear to show this connector. I was therefore wondering whether this connection a simple Hafler style output for a rear 'ambience' speaker? I've plugged a 3rd speaker into the connector and audio does indeed emanate from it. Does anybody know what this connection is for and / or have the schematic for this tuner amplifier which shows this connection. Regards Mark

29th Jul 2021, 7:04 pm	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Rogers Ravensbrook Third Channel Connection Two guesses... it could be a mono output or it could be an output if an optional board is added to decode the auxiliary channel. Sometimes called SCA or 'storecast' The Zenith pilot tone stereo system was designed with a bit of spare capacity which in some countries is used to distribute mind-numbing muzak to shops. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

29th Jul 2021, 9:29 pm	#3
tony brady Hexode Join Date: Mar 2014 Location: Peacehaven, East Sussex, UK. Posts: 278	Re: Rogers Ravensbrook Third Channel Connection I think it's most likely a Hafler style output. easy to test with the power off as the '3rd' speaker would hang between the positive outputs of the left & right channels, sometimes with a low value resistor in series. just do a continuity check from the positive pin of say the left channel and see if you have continuity to one of the connections on the 3rd din socket. do the same for the right channel