View Full Version : RCA TV Connections/Audio Amplifier

02-01-2007, 12:22 AM
Hey everyone,
I'm working on developing my own game console system based on the Propeller, and I'm designing a custom PCB for it,
I am not the best with electronics, I'm better at making components work together, but anyway,
What kind of wiring/connections do I need for TV output off the propeller? I havent found any information in any of the documentation such as a reccomended wiring scheme, etc.

Post Edited (Sachiel7) : 2/1/2007 12:26:10 AM GMT

02-01-2007, 12:26 AM
Look at the schematic for the Propeller Demo board. It's all there.


Sid Weaver
Don't have VGA?

Newzed@aol.com (mailto:Module?Newzed@aol.com)

02-01-2007, 07:21 AM
Thanks for the info,
I've found a good series of RCA Headers, but I've got another question now.
If you look at the Demo Board layout schematic, they're using a MAX4411ETP to amplify audio output for headphones.
I'm planning to have standard phono audio connections for TV, so, does anyone have any reccomendations on a different MAX amplifier IC I should use? Hopefully one that follows closely with the wiring scheme of the Demo board...

Mike Green
02-01-2007, 07:34 AM
The Hydra uses a similar low pass filter that just connects to a phono jack rather than running through an amplifier. You should be able to do the same thing using the Demo Board's component values, just leaving off the amplifier. Try it on a breadboard. The Hydra Manual goes into some detail on the choice of low pass filter values. You could also find some other discussions via a websearch.

Dennis Ferron
02-01-2007, 10:35 AM
I had a similar question a while back, and Paul Baker of Parallax gave me a circuit that has been working great for RCA audio out in my suitcase computer.

Here is a link to the forum post: http://forums.parallax.com/showthread.php?p=627929

Basically you just run the pin output through a 200 ohm resistor to provide the correct impedance, and use a .1 uF capacitor on the end of the resistor to ground to integrate the digital audio pulses. A 10 uF capacitor is used to couple the circuit to the RCA jack. It will make more sense if you look at the picture Paul drew.

Definitely copy the circuit of either the demo board or the Hydra, that way you will be able to run demo programs and games without modifying them to work with your set-up. I copied the demo board for my suitcase computer, and it is good that anything that runs on the demo board ought to run just as well on my suitcase computer.