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amp bias help needed

got a board for a dynast70 series II which I am running with iron from and original ST70.

sounds very good but the bias system in the st70 series II -- 2 LEDs between a pot on each channel -- is not quite right. the LEDs blink a lot, especially during loud/higher power passages.

to set the bias, you adjust the pot so that both LEDs are of equal light intensity. still blinks when I do this and also seems to drift out of equilibrium quite a bit.

thoughs?

I'm a semi-newbie and not a real electronics wiz.

some personal observations: ST70 series II is not tube rectified, so I am not using the two tube rectifying taps from the power transformer. could this be causing voltage increases in the other taps?

could an improper filter choke cause this, as I am using the choke per the original ST70.

thanks.



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Topic - amp bias help needed - dst 15:17:16 01/2/00 (4)


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