The first Carver amp, the M-400 did this in 1980. One channel inverted the signal and the other did not. The speaker terminals on one channel were swapped.
This was done so that the load on the "magnetic field" power supply would remain balanced for the heavy bass since it was essentially a 60Hz switcher that couldn't recover quickly, so it had a big output cap.
The schematic can be found on the web.
This was done so that the load on the "magnetic field" power supply would remain balanced for the heavy bass since it was essentially a 60Hz switcher that couldn't recover quickly, so it had a big output cap.
The schematic can be found on the web.
I was saying that if 1 channel is inverted and the other is not, then there is difference between the 2 channels. And that is bad.
Ripple will not disappear, it will be only less. Many DIYer simply use quite bigger supply then actually needed anyway. So it will not bring any nirvana. It may help in situations where you must get more juice from what you have, but if you plan well ahead, doesn't benefit much.
Inverting one channel input, then inverting the speaker, will mean that any even-order distortion will now be antiphase rather than inphase. This might be audible, although whether it will sound better or worse would need to be the result of well-thought-out experiments.
I was saying that if people can hear things that defy measurements, they must easily hear the very large improvements that can esily be measured and show to vastly improve performance! It doesn't make sense to avoid a clear and obvious improvement for something that some claim they can hear but what never has been confirmed in controlled tests.
Just sayin' 🙂
Jan
2 separate power supplies, one for each channel, is the best solution. Better than invert - invert.
I was about to agree, but thinking it over, are mono blocks really better in this respect? In theory they are, but in practice, it will all depend on practicalities.
The reason to put a question mark here is that with a single transformer and phase-antiphase connection (ST.PAC), the frequency of the current draw is doubled as compared to the monoblock situation (although the peak level of the current drawn will be the same). This means that you need double the total amount of reservoir caps in the mono block situation as compared to the ST.PAC configuration to get the same amount of ripple suppression.
So yes, mono blocks are better in theory, but besides adding a second transformer, you will also need to double the amount of capacitance as compared to ST.PAC, so it all boils down to a question of weight and cost versus effectiveness.
It might well be that for a given budget, if you invest the additional costs that mono blocks would entail in a larger transformer and more capacitance in an ST.PAC, the end result of the latter would be better. As a matter of fact, it stands to logic that it is, up to a certain point. To find that point is a much bigger challenge than to reinvent the idea itself.
It was all the fashion many years ago in the HiFi mags, then (like most fashions) it died out. If it was the 'solution' I guess all amps would be made that way.
Agree. Class A should have constant current, nothing to do with frequency. If your amplifier draws more current at lower frequency as suggested by OP then you have been doing wrong, always.
A long time ago I did have a Class B amp. A long time ago, this technique was widely discussed as suggested by Mr Onion. I tried it, like I tried many tweaks, and didn't hear much difference. IIRC correctly, I achieved phase reversal one channel by reversing the cartridge leads on my Grado, then reversing speaker leads.
I think a local guy here in Melbourne Australia was doing this years ago (20 or 30yrs) and it was known as "Oops".........Out Of Phase. (Just reverse the input and output of one channel.)
As far as I remember, the schematics were fully complementary with differential inputs with only a resistor to load the emitters of each pair.
There was a dedicated circuit to invert polarity on one channel.
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