Negative output impedance

[Rikard Nilsson]

I´m contemplating some ideas just for fun. Would you say negative output impedance from an amp would be a good thing? Theoretically, if matched correctly with the voice coil resistance it could be used to cancel out the resistance and obtain a very good damping factor, right?

Or is it wrong to assume that the voice coil resistance should be added to the amps output impedance, effectively ruining any small benefits from lowering the amp output impedance to zero?

[VladimirK]

Originally Posted by Rikard Nilsson

I´m contemplating some ideas just for fun. Would you say negative output impedance from an amp would be a good thing? Theoretically, if matched correctly with the voice coil resistance it could be used to cancel out the resistance and obtain a very good damping factor, right?

Or is it wrong to assume that the voice coil resistance should be added to the amps output impedance, effectively ruining any small benefits from lowering the amp output impedance to zero?

Speaker manufacturers usually want that their products would fit into a standard situation - amp's output impedance is close to zero. Providing negative Zout will not guarantee that sound will be better, anything could happen, but improvement is hardly expected.
I would love an opposite idea - trying a transconductance amp (Zout is rather high, near 40 Ohms as tested by Nelson Pass). Some speakers sound excellent under such conditions.

[SoNic_real_one]

The maximum power transfer is achieved when the output RESISTANCE is equal to the speaker one and the output REACTANCE is opposite sign and equal with the one of the speaker.

[sregor]

Originally Posted by SoNic_real_one

The maximum power transfer is achieved when the output RESISTANCE is equal to the speaker one and the output REACTANCE is opposite sign and equal with the one of the speaker.

I disagree - I was taught that maximum power transfer is achieved when the LOAD resistance = source resistance - for a modern amplifier this would mean the lower the resistance, the more power transferred which agrees with what I've seen in the real world. my 2 cents

It's also getting away to the OP original query.

[VladimirK]

The question here is not about optimal power transfer, it is about best sound quality from the amp-speakers system. And speakers are usually designed and tested with some real amp, having 0,01...0,1 Ohms Zout modulus.

[phase_accurate]

Those who know how to use the search function

1) wouldn't need to open a new thread and
2) would find a lot of interesting answers

;-)

Regards

Charles

[Rikard Nilsson]

Originally Posted by phase_accurate

Those who know how to use the search function

1) wouldn't need to open a new thread and
2) would find a lot of interesting answers

;-)

Regards

Charles

Well, sorry for being such a pain.....