UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - My first valve radio project

Ed_Dinning · 28th Dec 2016, 9:28 pm

Hi Nicola, the 2 resistors are to give a small degree of isolation to the stereo channels. They also act as safety resistor if something go wrong on the radio and it will not incinerate your player.

These sets were often designed to run from high output record player cartridges, perhaps up to 1 volt. Do you know, or can you measure (scope preferably) the output of your player?
Does this drop significantly when connected to the radio?
Some players have been used with a small IC amplifier to boost the sound.

Not sure of your circuit, but check to see if the cap in series with the tone control is OK, if it has gone low resistance, it will shunt the output transformer and reduce volume as you describe.

Note that some sets used the on/off switch on the tone, not vol control (to save wear and tear.

Ed

28th Dec 2016, 9:28 pm	#179
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: My first valve radio project - Philips 462A Hi Nicola, the 2 resistors are to give a small degree of isolation to the stereo channels. They also act as safety resistor if something go wrong on the radio and it will not incinerate your player. These sets were often designed to run from high output record player cartridges, perhaps up to 1 volt. Do you know, or can you measure (scope preferably) the output of your player? Does this drop significantly when connected to the radio? Some players have been used with a small IC amplifier to boost the sound. Not sure of your circuit, but check to see if the cap in series with the tone control is OK, if it has gone low resistance, it will shunt the output transformer and reduce volume as you describe. Note that some sets used the on/off switch on the tone, not vol control (to save wear and tear. Ed