Balanced input phono stage

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cressy
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#1 Balanced input phono stage

Post by cressy »

Hi guys, i have been musing about balanced phono stages for a while and have a pretty simplistic idea in mind.
My understanding is that a cart is balanced anyway, that the green and blue pins on the back of the cart actually output an inverted version of what is coming out of the red and white pins. And in the usual configuration the green and blue pins simply are conected to earth and discard this signal.
So for a balanced phono stage there is no need for a phase splitter as it is already split.
If my assumption is correct then can a phono stage be designed in a similar way to a push pull output stage?

What i have in mind is essentially a doubled up version of my nuvistor one where there are 4 'channels' one each for the red, white, green and blue with an initial gain stage, riaa network and second gain stage.

The bit i am mulling over is how to output this.

The reason being that if i use a set of transformers to give a single ended output im wondering if there is any advantage to the topology.

Presumably this way there will be noise cancellation so i should end up with something quiet

Something worth lookkng into?
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Nick
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#2 Re: Balanced input phono stage

Post by Nick »

My understanding is that a cart is balanced anyway, that the green and blue pins on the back of the cart actually output an inverted version of what is coming out of the red and white pins.
Its balanced in that the output is floating. If you round one side, its single ended, if you don’t its floating. Nothing can "come out" of one side of the coil, if nothing can "go in" to the other. Of course out and in are of no meaning as its AC and there is no 0v.
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cressy
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#3 Re: Balanced input phono stage

Post by cressy »

More reading required then, mark provided me with some links to look through so i'll start there
Cheers ant
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