Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

Maurits.Eycken@soc.kuleuven.ac.be

: Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

: I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

: It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

: Maurits.Eycken@soc.kuleuven.ac.be

Hi Maurits, I think you'll find that the volume control has the centre tap to earth. the anti clockwise end to the aerial and the clockwise end to the cathode(s) of the RF/If amplifier(s). As the control is turned down from maximum it progressively shorts out the aerial and reduces the amplifier gain by increasing the cathode bias. Your set might use separate pots of different values to get better balance between the two functions. I'm keeping my eye open for a circuit, if I find one I'll send it on. Don.

: : Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

: : I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

: : It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

: : Maurits.Eycken@soc.kuleuven.ac.be

: Hi Maurits, I think you'll find that the volume control has the centre tap to earth. the anti clockwise end to the aerial and the clockwise end to the cathode(s) of the RF/If amplifier(s). As the control is turned down from maximum it progressively shorts out the aerial and reduces the amplifier gain by increasing the cathode bias. Your set might use separate pots of different values to get better balance between the two functions. I'm keeping my eye open for a circuit, if I find one I'll send it on. Don.

Gentlemen,
The circuit for the Philco 20 may give you some clues to this system-it has both the antenna and cathode biasing ciruits controlled by a double potentiometer.

Bob Rosengarten

: : : Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

: : : I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

: : : It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

: : : Maurits.Eycken@soc.kuleuven.ac.be

: : Hi Maurits, I think you'll find that the volume control has the centre tap to earth. the anti clockwise end to the aerial and the clockwise end to the cathode(s) of the RF/If amplifier(s). As the control is turned down from maximum it progressively shorts out the aerial and reduces the amplifier gain by increasing the cathode bias. Your set might use separate pots of different values to get better balance between the two functions. I'm keeping my eye open for a circuit, if I find one I'll send it on. Don.

: Gentlemen,
: The circuit for the Philco 20 may give you some clues to this system-it has both the antenna and cathode biasing ciruits controlled by a double potentiometer.

: Bob Rosengarten

The AVC control, as described above is also used, in my Philco model 252 and my Sonora Sonorette model 855D. However, in these cases only one potentiometer does the job.
These radios are described on my homepage http://www.gironet.nl/home/gverhe/home.html and include the schematics of the Sonora.

Gidi Verheijen

: Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

: I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

: It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

: Maurits.Eycken@soc.kuleuven.ac.be

: : Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

: : I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

: : It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

: : Maurits.Eycken@soc.kuleuven.ac.be

FOUND IT

I could figure out the circuit and localize each part of it.

Thanks anyway for the comment

Maurits

: Can somebody explain or drawn me the circuit of the double volumepotentiometer in a set without AVC.

: I know that the middle tap of the potentiometer is connected to earth and one of the others is connected to the antenne to reduce the antenna signal, but I don’t find out the third connection.

: It is a circuit used in a HMV model 238 AC (1934-1936 ?) (still searching for schematic diagram)

: Maurits.Eycken@soc.kuleuven.ac.be