Using virtual center tap for a power amp ?

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#22
If one uses a bridged output, the "GND" is only a reference potential, no power currents involved. One can make a bridged amp with only one high-Z GND connection, derived from a 1:1 divider of the rail voltage (with caution, e.g. snubbers etc must return to the rail, not GND).

But, looking closer, all amps, by neccessity, are bridge configs in the end, just that sometimes one of the bridge halves is passive (center tapped xformer or two flaoting supplies connected at one "center" point) or active (this virtual GND stuff here) but not driven with any signal (as it is in a real bridge amp). The choice of which point is labelled GND is somewhat arbitrary (of course one might need level shifter -- eg. xformers -- at the input). The quality of both bridge parts determines sound quality, as they are always in series -- as is the whole supply, WRT to the output current, which is a current *loop*, returning to the point it came from and getting level-shifted (from the voltage view) over and over again (the essence of supplying power to a circuit).

- Klaus
 
#26
I do not like to have doubts...when i have i use to test

Quad 306 was constructed.... perceived the bass not good.... then i increase the input capacitor...bass more strong but undefined.

Also, using the supply without center tap i tried my own amplifier, to see if the loosen, undefined bass.... distant...not present...not clear...if this would repeat into my amplifier.

And i have obtained the same result.

The difference i had in my amplifier, the technical difference was the supply.

Works...for sure without center tap works!..... 30 years ago i could not make it work..... now i could...but do not sounds fine to my subjective evaluation.

Of course...others can feel different...of course.

bye folks... chapter closed to me...tested!

regards,

Carlos
 
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