[taoster]

sorry for this silly question but i need help. I purchased a potentiometer to build an attenuator with and I am planning to try with a small 1K linear pot to start. ( i understand i should be looking at a LOG or use a high quality resistor to make it LOG in character)

the pot has 3 prongs. what's what? can someone help me out?

I have the following 3 comopnents:

RCA
RCA1 LEFT
RCA2 GND
RCA3 RIGHT

POT(looking from top with prongs facing south)
prong 1(left most)
prong 2(middle)
prong 3(right most)

HEADPHONE SOCKET
TIP
RI(the other bit i guess)
GND


Right now, its connected with the RCA to the HEADPHONE SOCKET.
RCA1->TIP
RCA2->GND
RCA3->RI

how do i add the POT to it so i can decrease volume level?

thanks for reading and sorry for such a beginner question.

 

[Squalish]

Not quite sure what you mean by the RCA stuff.

You should have:
RCA LEFT SIGNAL
RCA LEFT GND
RCA RIGHT SIGNAL
RCA RIGHT GND
I don't understand this RCA1/2/3 thing you're describing.

A pot typically is a length of conductive plastic or carbon that acts as a resistor, and a metal wiper that moves across it. At each end of the resistive track, there is a contact. When the metal wiper is closer to one contact, there is less resistive material in the way, and there is less resistance. This allows more current to pass through it, increasing the volume.

The pot should be connected to the RCA input signal on one end, ground on the other end, and the wiper should be connected to the amp's imput cap, or for just an attenuator, to the output jack. These three pins are used for each channel.
The datasheet for your pot should tell you which pin is which.

What exactly are you making?
If its an amp, then the output would go to the headphone jack. If you're just making an attenuator, then it would go from the pot's wiper to the jack. The jacks are wired differently depending on model, just like the pots are, so you'll need to check the datasheet if you're looking at an enclosed jack(for an open jack you can see with your eyes). IIRC, the left channel is the tip, the right channel is the ring, and the ground is the sleeve.

 

[puppyslugg]

It sounds like you're using a mono pot. Is this correct?

 

[taoster]

hi

i am trying to make a simple attenuator with RCA as input, a pot for volume control and a headphone socket-out. yeah, thats it lol

Squalish;
the rca post thing has both the left and right channel ground already connected. so there is only RCA LEFT SIGNAL, RCA RIGHT SIGNAL and Ground(both left and right ground connected already).

re POT, the pot didnt actually come with a datasheet.. and im not quite sure if its the right kind of POT to use.

the POT should be in series to the circuit?? ohh.. i see.. i need a dual POT?!?! one for the left and the other for the right signal?? (or 2 mono) is that right? both connected in series to the signal path... ahhh its beginning to make sense hahaa thanks.

this is the pot that i am currently attempting to connect with:
pot without a datasheet, how do i know which is in,gnd, out. the middle pin is gnd? and the other 2 dont matter so much as long as its in series??

 

[Squalish]

The "in/out" pins of the pot, as you term them, can be flipped with the only result being a change in the rotation of the knob(IE from clockwise=increase volume to clockwise=decrease volume).

To find these "fixed" pins, ff you measure w/ a multimeter between them, you should have the pot's value(1Kohms you said). Both of them should have variable resistances when they are each measured against the wiper pin.

And yes, for stereo sound, you will need a dual channel pot, although you could use a 1 channel pot just fine for 1 channel.

 

[stereth]

Yes, you need a dual pot. No way around it. Look here, specifically the second and third diagrams, for some example schematics to see how to wire the pot.

You also need to check the value of the pot. Recommended values are 10K to 50K ohms. Make sure to get an audio/log taper pot.

Also look here for more specific information.

 

[taoster]

stereth, thanks for the pot spec!

Squalish, thanks for clearing everything up! much thanks.

from discussions with Jazz, i believe the 500ohm pot is ideal for my need due to impendence match with phone. if its 10K-50K the phone cant be driven directly by the line-out. so i believe..

there doesnt seem to be much 500ohm pots out there though