Tech help: Jamma Mono to Stereo

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capcomguru
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Tech help: Jamma Mono to Stereo

Post by capcomguru »

Hi Everyone-

I'm having a bit of a problem. I recently did a Power Supply and Audio amp upgrade on my New Astro city. The power supply I installed has an internal audio amp, but its no good. Since the amp was no good, I decided to install a QSound amp instead. The audio is STELLAR for stereo games. Only problem, I can't do mono as of right now.

So here's my question. Whats the best way to take Jamma mono audio and split it to Red/White RCA jacks? I was thinking I'd make a break-out adapter, and physically split the mono line and speaker ground over the stereo jacks. My question is will the Jamma PCB's audio amp conflict with the QSound's audio amp? I'm sure I'll need to make sure the audio is turned way down on all my jamma's before i power them up, just want to be sure I don't blow any of my amps up.

Would it be a good idea to put an attenuation circuit on the new "stereo" lines? (By stereo I mean mono split over two inputs).

Any help would be greatly appreciated!
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Chi
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Re: Tech help: Jamma Mono to Stereo

Post by Chi »

You would be better off making a switch to route the mono and stereo to the speakers seperately, so that at any time only one input is connected. A double pole double throw switch should do the trick.
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Flazh

Re: Tech help: Jamma Mono to Stereo

Post by Flazh »

You should use diodes for this. Then you won't have any problem with amplified voltage going into the speaker terminals. Either that or somehow get the voltage down to levels where you could input the mono signal through a splitter and into the audio amp.
capcomguru
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Re: Tech help: Jamma Mono to Stereo

Post by capcomguru »

I ended up building a quick attenuation circuit which is built into a Jamma pass through harness.

Basically, it takes the amplified jamma mono audio and drops it to line level. I put a 100kohm resistor on the + line and a 10kohm resistor on the - line. After the audio was attenuated, I have it splitting to female stereo RCA leads. From there, I patch the split mono audio into my qsound amp. Best of all, the volume control on my PCB's still works! Woohoo!
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