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Radio Shack MPA-250B Stereo Amplifier

T

transformer8

New Member
I have the Radio Shack stereo amp as noted in the title. I want to amplify my computer sound card. It is stereo. The common, the left speaker and the right speaker in the tip, ring and sleeve. The problem is that my wonderful RS stereo amp has an input consisting of two 1/4 inch stereo inputs. All the other inputs are two pole, or monophonic, except for one which consists of two, two pole RCA inputs. Anyone know WHY Radio Shack created such an arrangement? I thought I'd take the tip of my computer output and attach it to the tip of one of the 1/4 inch amp inputs and attach the ring from the computer output to the ring of the other 1/4 inch amp inputs. The computer output sleeve will bifurcate and attach to both 1/4 inch input sleeves. The amp diagram said the 1/4 inch inputs were "balanced".
 
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The RS MPA250B is a Public Adress amplifier and is configured to work with different sources, 1/4 inch jacks or RCA phono plugs. If you are feeding a mono source ,such as a guitar, the right hand 1/4 inch jack is for that. You want to feed the RCA inputs on your amp from your computer. Radio shack has an adaptor cable with a stereo mini jack on one end and two RCA phono jacks on the other. Plug it into the audio out Jack
on your sound card and connect the two RCA plugs into your amp and you are good to go.
 
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The 250A and 250B mixers are totally mono. Only the RCA inputs into the amplifier part are stereo. So the mini to rca splitter (or cable) is the only way to get stereo. Should be able to get either at Radio Shack, or Monoprice or Amazon or Ebay or ...
 
transformer8 said:
I have the Radio Shack stereo amp as noted in the title. I want to amplify my computer sound card. It is stereo. The common, the left speaker and the right speaker in the tip, ring and sleeve. The problem is that my wonderful RS stereo amp has an input consisting of two 1/4 inch stereo inputs. All the other inputs are two pole, or monophonic, except for one which consists of two, two pole RCA inputs. Anyone know WHY Radio Shack created such an arrangement? I thought I'd take the tip of my computer output and attach it to the tip of one of the 1/4 inch amp inputs and attach the ring from the computer output to the ring of the other 1/4 inch amp inputs. The computer output sleeve will bifurcate and attach to both 1/4 inch input sleeves. The amp diagram said the 1/4 inch inputs were "balanced".
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The 1/4" inputs on the amp are not stereo like on the sound card minijack. They are balanced TRS inputs so you'd need a cable to convert the stereo minijack to individual left and right 1/4" TS plugs.

However, the suggestion to use a stereo miniplug to left/right RCA adapter is good since those cables are easy to get.

http://www.monoprice.com/Product?c_id=102&cp_id=10218&cs_id=1021815&p_id=5598&seq=1&format=2
 
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