Hello out there. I am into old tube console stereos and was thinking about turning some phono only ones into AM source also. I have an AM transmitter and some old AM radios and am not expert enough to try it on my own. Has anyone done this or can you help me figure out how to tap the output of a radio? If it's not too difficult I would love to try it. Thanks in advance!

Mark

On your speaker there will be two wires going to the cone. Try connecting to these wires to take a signal from the radio. This is the easiest as it doesn't require connecting to chassis circuitry.

Only a small voltage (1 volt) will be on these wires which is dependent on volume.

Norm

:Hello out there. I am into old tube console stereos and was thinking about turning some phono only ones into AM source also. I have an AM transmitter and some old AM radios and am not expert enough to try it on my own. Has anyone done this or can you help me figure out how to tap the output of a radio? If it's not too difficult I would love to try it. Thanks in advance!
:

Will this work OK? It sounds like I'd be connecting the driver output to my amp phono input. The console has an amp of it's own and are usually push pull outputs. Also they have 12 or 15 inch woofers! Thanks
:Mark
:
: On your speaker there will be two wires going to the cone. Try connecting to these wires to take a signal from the radio. This is the easiest as it doesn't require connecting to chassis circuitry.
:
: Only a small voltage (1 volt) will be on these wires which is dependent on volume.
:
:Norm
:
:
::Hello out there. I am into old tube console stereos and was thinking about turning some phono only ones into AM source also. I have an AM transmitter and some old AM radios and am not expert enough to try it on my own. Has anyone done this or can you help me figure out how to tap the output of a radio? If it's not too difficult I would love to try it. Thanks in advance!
::
:
:

Mark

Not sure what you are trying to do. If driving a 1 tube transmitter speaker voice coil will work and is isolated from the rest of a tube radio circuit.

If you want a phono input connect a shielded cable to the volume control. There will be three terminals. Ground the shield. Connect center wire to the center terminal. This is a low level signal and will give hum if not shielded.

Norm

:Will this work OK? It sounds like I'd be connecting the driver output to my amp phono input. The console has an amp of it's own and are usually push pull outputs. Also they have 12 or 15 inch woofers! Thanks
::Mark
::
:: On your speaker there will be two wires going to the cone. Try connecting to these wires to take a signal from the radio. This is the easiest as it doesn't require connecting to chassis circuitry.
::
:: Only a small voltage (1 volt) will be on these wires which is dependent on volume.
::
::Norm
::
::
:::Hello out there. I am into old tube console stereos and was thinking about turning some phono only ones into AM source also. I have an AM transmitter and some old AM radios and am not expert enough to try it on my own. Has anyone done this or can you help me figure out how to tap the output of a radio? If it's not too difficult I would love to try it. Thanks in advance!
:::
::
::
:
:

I think what is trying to be done is to take the AF from a radio, then run that into the phono input of a phonograph amplifier. The problem would be the potential of ground ( hot chassis ) from radio to phonograph input.

:I think what is trying to be done is to take the AF from a radio, then run that into the phono input of a phonograph amplifier. The problem would be the potential of ground ( hot chassis ) from radio to phonograph input.
:
That's exactly what I'm attempting to do. Most radio/phono units have the phono input switched into the stream of the radio amp circuit. And they usually have a schematic attached but they are so small that they are useless. I'll have to do some homework. Thanks

I'm visualizing a couple of problems here - that should be solvable.

A phono-only amp will have an RIAA equalization circuit at the front end. For any input except a phono, this will need to be switched out. You can Google for more info on RIAA equalization.

Secondly, a typical phono cartridge has an output of just a few milivolts. So, a higher level input (including Norm's suggestion) will be too high and cause major distortion. The input could be attenuated with a voltage divider. Or, since a phono amp will have a preamp stage - that stage could be bypassed.

With your stereo amp, each channel will have its own separate RIAA equalization circuit and preamp stage.

::I think what is trying to be done is to take the AF from a radio, then run that into the phono input of a phonograph amplifier. The problem would be the potential of ground ( hot chassis ) from radio to phonograph input.
::
:That's exactly what I'm attempting to do. Most radio/phono units have the phono input switched into the stream of the radio amp circuit. And they usually have a schematic attached but they are so small that they are useless. I'll have to do some homework. Thanks
: