Hmm, the TDA2822 does have a "bridge" mode where it is wired up with the two amps
out of phase to drive a speaker without needing output caps.
Is that what you are referring to?
The uBitx does not use bridge mode, the second section of the TDA2822 is left unused.
So the output load is between the amp output pin and ground,
allows the headphone jack to have the return at ground potential.
A DC blocking cap (C77 in the uBitx) is required.
> Shorting the output keeps both legs of it above ground.
Perhaps you mean that if we were in bridge mode with a 0 ohm load,
both sides of the load would wind up at a voltage above ground?
Jerry
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On Thu, Mar 1, 2018 at 10:29 am, Dexter N Muir wrote:
Read the thread/s thoroughly, Raj (and all). Shorting the output keeps both legs of it above ground. It would seem that taking either leg to ground (that 'ring' connection that is taken there by a mono plug in particular) does the damage. It's the 'cheapo' method of boosting audio output: bi-phase two amps: 4x the power from the same supply voltage. This package evidently does this internally. If the spec sheet shows the internal circuit, this becomes obvious. I await reports...
