Wiring of pot resistor (potention meter)

Hi Guys,

I am taking a Hi-Fi speaker output into an FM modulator.

I realise that the FM modulator has a lower input, therefore I am building a small circuit between the Hi-Fi and the FM modulator with a pot resistor to bring down the speaker volume to an acceptable range for the FM modulator input.

I am using a pot resistor (502 6P1-38).
The problem I am experiencing is with the pin layout of the pot resistor.
I learned online that pin number 1 should be earth, nr 2 input and nr 3 output.

From the Hi-Fi I have two wires. (Standard speaker output).

I've connected the first wire straight through to the FM modulator, and the second wire to the first pin of the pot resistor. From the second pin of the resistor to the second wire of the FM modulator input. Adjusting the pot resistor I am getting a Slight variance in volume.

I've also tried pins 2 & 3, but with the same result. Should the pot resistor not work the same as a light dimmer, it should be able to mute the volume completely?

What am I doing wrong here?

- - - Updated - - -

Hi Guys,

I've done a little more reading up, and it seems that I am going to be better off with a volume control, rather than using a pot resistor.

"A volume control for one channel has 3 terminals. One is from the music source, one is ground and one connects to the input of the FM modulator. They must be connected properly for the volume control to work properly."

"If the music source has an output of 0.3V then when it is connected to a 47k volume control the power in the volume control is (0.3V squared/47k)= 0.0000019W which will not destroy the volume control"

A potentiometer is a resistor (that you can measure with an ohm-meter) and a slider that can slide along the resistor from one end to the other end.
The signal source is connected across the resistor part with the signal at one end and the ground at the other end. The output of the pot (or volume control) is the slider and ground.

When the pot is turned clockwise the output level is the same as the input signal level. When the pot is turned anti-clockwise the output is ground (no signal).

Additional comment.

- We can't know if "pin nr. 3" is actually the potentiometer slider. In many datasheets, the slider is marked as pin 2.
- The "standard speaker output" may be from a bridge amplifier. In this case, none of it's terminals is grounded and never must be grounded. Respectively the "FM modulator" must have no ground connection either.