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What would it take to balance a stereo power amp ?

I am in a band and own the P.A. system that we use . In the interest of eliminating hum and noise I have decided to run it balanced . The main FOH system is tri-amped with an electronic crossover going into three seperate stereo power amps. Two of them have balanced inputs but one of them does not . The "unbalanced" amp is an older model that has given me years of trusty service and I don't want to replace it if unnecessary to do so . What would it take to balance it ?
Obviously , it would have to be an inexpensive retrofit or it wouldn't be worth the cost or aggravation . Any help would be greatly appreciated .
dicehead
jjwinterberg
45 posts
 
Dice,

Actually Ghostrider is correct. A component must be designed to be balanced or it just won't be balanced.

What Bob is refering to is running a balanced connection between components. And Bob and TWL are correct that this is possible and only requires a set of balanced to single ended transformers. If the noise is caused by pickup in the interconnects then the balanced cables will produce a benifit. If the noise pickup comes from other sources, then the advice from Driver should be helpful.

I think you should use both suggestions for best results.

Regards,

John
nrchy's avatar
nrchy
2,124 posts
 
Both groups are right as far as they go.

1) Balanced outputs can be added to anything.
2) Having XLR outputs does not make the piece balanced. This is a design issue which obviously involves more than just outputs. Balanced circuitry is balanced throughout.

Whether or not this alteration will eliminate the 'hum and noise' is not certain, but your proposed solution is fairly inexpensive and easy to accomplish.
dicehead OP
2 posts
 
Opinions seem to divided on the possibility of balancing a non-balanced amp . I am no electronics wizard by any means but am not afraid to tinker with the insides of my gear . I never did believe the warning - " No user serviceable parts inside !" Does any one know of a circuit diagram or a place to come up with one ?
kr4's avatar
kr4
3,677 posts
 
Opinions may seem to be divided but Nrchy is correct.(1) You cannot easily balance a non-balanced amp but (2) you can make it compatible with balanced sources.

You also ask: "Does any one know of a circuit diagram or a place to come up with one ?" Assuming you mean adding an input transformer for (2), others will suggest specifics. If you mean (1), then you have to tell us what the amp is and provide the original schematic.
twl
3,251 posts
 
Of course, I'm sure you realize that I wasn't inferring that adding the adapters would change the topology of the amp to balanced. The adapters are simply a way to allow him to use the cabling he wants.
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