Basic Volume Circuit

[quixote171]

I've done some poking about but so far I'm unabvle to find the answers I need...

Here's the problem.

I have a 101 Disc CD Changer with no volume control running directly into a PA system at work. The PA's volume control is extremely touchy and is either off or blaring.

I'd like to build a small box to insert between them - two rca inputs, two rca outputs and a volume knob. It doesn't need to be fancy I just don't have the technical knowledge to create it. I'm sure I can build it, I just don't know where to start.

Any help would be greatly appreciated.

Thanks!

[BWRX]

http://sound.westhost.com/pots.htm

That's a great page to get you up to speed on all you need to know about making a very simple volume control.

[Nigel Goodwin]

Originally posted by quixote171

I have a 101 Disc CD Changer with no volume control running directly into a PA system at work. The PA's volume control is extremely touchy and is either off or blaring.

Why not just repair the existing control?, either replace the control or give it a squirt of contact cleaner - personally I find simple WD40 is BETTER than specific contact cleaner, but many people disagree! (however, I've been using it professionally for over 25 years).

[sreten]

Hi,

your CD player probably has ~ 2V output whilst the PA
input could easily be ~ 100mV input, i.e. far too sensitive.

All you need to do is make up a dual phono to phono cable,
and use good sized plugs at the far end with enough room.

At the far (PA) end solder in a 10K series resistor and 1K
parallel (i.e. 1K resistor pin to case, 10K pin to signal).

job done.

/sreten.

[quixote171]

Thanks very much! I think that's just what I needed!

[quixote171]

One more question!

The wiring diagrams I'm looking at show two pots - one for the left channel and one for the right channel. How would I make one volume control to regulate both at the same time?
Forgive me if I'm asking silly questions - I'm a total noob.

Thanks again.

[pburke]

Originally posted by quixote171
One more question!

The wiring diagrams I'm looking at show two pots - one for the left channel and one for the right channel. How would I make one volume control to regulate both at the same time?
Forgive me if I'm asking silly questions - I'm a total noob.

Thanks again.

you use a stereo pot (that's two in one)

[AndrewT]

Hi,
if you make up the two resistor attenuator as in post4 you do not need another pot. The attenuator alone will give about 20db of cut and should bring the existing volume control back to a sensible control rotation.

Provided the volume control on the PA is working properly. Could it have a broken track?

[quixote171]

I built the stereo pot and four rca jacks into a small radioshack project box - I haven't used it on the PA yet, but it seems to function properly in my home tests...

Thanks everyone!