In Line RCA Attenuators

[sixstringphil]

Sorry to veer off the stompbox path, but this might help me better understand some of the basics...

Problem: I have a video game system that is overdriving the audio inputs on my television. No way of dialing it back that I know of.
Solution from others: In-line RCA attenuators like these (http://www.enjoythemusic.com/magazine/equipment/0803/rothwell.htm)

Would anyone be able to help explain or point me to an explanation of how this works. Seems like it must be pretty simple. This would be the same as a pad on a direct box, correct?
I pretty well understand the construction, but not the theory. How should I go about calculating resistor values?

Also, they're available with different decibel reductions. (3, 6, 10, 12, etc.) Could this be made variable with a pot?

Thanks!!

[John Lyons]

Just rig up a volume pot on one channel to test, maybe 50K or 100K in between two RCA cords and see what you come up with.
Dial it back and see where the best setting is.
Measure the resistance between the wiper and ground and the wiper and lug 3/Hot.
Then make yourself a couple RCA pad with those resistances as fixed resistors.
You'll probably have to round up or down a little to use standard value parts.

Funny that it's overdriving the TV though...

John

[sixstringphil]

Thanks John. That's what I would have thought. However, in the article, it describes a resistor connected from hot to ground, but also one connecting both of the hot pins. I think I understand how the volume pot connecting the hot to ground pins works, but what would the purpose of the resistor across both hot pins be?

Here's a quote from the article...
These attenuators are made by taking a male RCA plus barrel and soldering a female RCA plug to the other end of this barrel. Inside the barrel there are two tiny resistors, one soldered from the hot centre pin of the male to the hot inner sleeve of the female. The other resistor is soldered in "shunt" which means it goes across the connector. This resistor connects the hot centre pin of the male RCA to its ground section. Then the resistors are siliconed inside the barrel. The connector can be opened by unscrewing the barrel from the male RCA end. Use a wide rubber band on both these surfaces to get a better grip and unscrewing the male RCA jack from the barrel. These two resistors, one in "series" and the other in "shunt" produce the 10dB attenuation through the attenuator.

So, that would be something like this.... But why the resistor from + to + ?
                     
           (+)  ---/\/\/---  (+)
      /        |                          \
male     (pot)                      female
      \        |                          /
            (-)                  ( -)





Thanks!