What IS Pioneer's NON_SWITCHING??????
I was going to bite my tongue here, but after THAT, I can't remain silent...
It has
nothing to do with anything like switching power supplies.
Let's start with something EVERYBODY is familiar with: Idle current through the output transistors.
WHY do we have idle curent - to reduce CROSSOVER distortion.
What is CROSSOVER distortion?
Wiki link to crossover distortion. ( not needed to understand, but it's here)
Amplifier output circuits have TWO transistors, to drive the positive and negative sides of the waveform. Push - Pull. But when the puller is pulling the pusher stops, and when the pusher is pushing - the puller stops - neither can do the other's job - they just get out of the way.
CROSSOVER distortion is the distortion caused when one of the two sides (positive or negative) of the the output transistors "hands off or transfers" the job of driving the speakers to the OTHER side.
Why does it happen: it takes time for the other side to "wake up" when it gets the message (voltage) to get to work. Waking up = SWITCHING ON .... How well do you bounce out of bed every morning?
SO, we TRY to keep both output transistors awake continuously by running IDLE CURRENT through them at all times. There's been a simple circuit that has done relatively well for a long time - BUT IF YOU WANT TO GET VERY VERY PICKY, IT HAS A FAULT.
-- -- --- -- -- -- all this ^^^^ is
familiar territory we all deal with, .... here comes the NEW stuff!! -- --- --- -- -- -- -- --
The fault is that the positive signal (or vice - versa) eventually DOES
completely turn off the negative side.... NO IDLE CURRENT FLOWS - THE NEGATIVE SIDE TRANSISTOR IS ASLEEP - SWITCHED OFF ..... (or the negative signal does completely turn off the positive side)
The crossover distortion in a conventional idle current circuit is reduced because when the signal is returning to where that side WILL be turned on, the conventional idle current circuit gives the signal to those transistors a little
head start to wake up.
The NSA part of the amp does something DECEPTIVELY SIMPLER!!! (with circuits that are a HE## of a lot more complicated) .
It NEVER NEVER EVER lets EITHER side BE TURNED OFF !!!!
It CHOPS OFF THE PART OF THE SIGNAL GOING TO THAT SIDE (positive or negative) THAT WOULD TURN THE TRANSISTOR OFF - THE IDLE CURRENT NEVER STOPS FLOWING IN EITHER TRANSISTOR
EVER.
NON-SWITCHING (off)....
The two different chopped up signals, each sent to IT'S half of the output transistor circuit combine at the output to make an extremely low distortion result.
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So there you go, not as elegant an example as explaining a 4 stroke gasoline engine as : SUCK SQUEEZE POP PHOOEY... but it'll do.
