Inverted or non-inverted... that's the problem

[purplepeople]

Originally posted by Richard C


In a domestic hi-fi set-up, odd numbers of inverting gain-stages don't necessarily require evening-up with an extra inverting stage, simply make the correction at the loudspeaker end.

Aternatively: inverting pre-amp followed by inverting power amp = no unecessary gain stages and no change at the speaker end.

Yes, if the equipment is DIY, hence the many IGC circuits here on this forum. But a fab that makes a component (like pre, eq, xo or amp) has no idea how the user will connect any products and so must make it with the input polarity the same as output polarity. Although it is possible to make an inverting component that is connect in reverse polarity like the IGC, there must be a reason for using the non-inverting opamp inputs - maybe for buffering components, the analog grounds must all match for best overall system performance.

:)ensen.

[Faber]

Thank you all for your answers.

I will probably use the inverting input on the GC, but I will test also the non inverting, just to listen how it sounds.

In addition, I will try to build a bridged clone and listen at it to view if it reach a right medium between inverting/non-inverting input sound :-)

Thank you again.
Bye, Fabrizio

[KURT]

Hi everyone,
National Semiconductor says that the inverting amplifier can have better THD+N performance in the datasheet of the LM4780 on page 19!!! (search with Google)

Best regards
Kurt

[ir]

yeah it does

saw it yesterday. it hasa short, two sentence paragraph staing the amplifier can be wired for inverting mode for slightly better THD

but thats all they say.

obviously National don't see it as being of huge benefit - and they make the things

[Morse]

Hi Peranders;

>>>...I think many people will endure 0.1% dist. Ask the tube guys...<<<

*LOL!* You got that right! ;-) My 2A3 is far worse than that on paper....but it sounds so, so sweet even so. IOW, it's the kind of distortion as much as the amount that really matters - I got over worrying about numbers a long time ago, so long as the end result is "good" to my admittedly aging ears. Just my 2 pence, natuerlich.

All the best!
Morse