Are all amps being built wrong?


The power amplifiers that drive our loudspeakers are mostly built as a low impedance voltage source. They have always been ... but why?

Loudspeakers have a (greatly) varying impedance over the frequency range. A current drive amplifier would eliminate the issues that stem from this varying impedance, and at the same time make discussions about esoteric speaker cables that strive for optimal R, C, L superfluous. Although there still would be these un-measurable ’this (very expensive) cable sounds better’ debates and opinions ... and that’s OK, that’s part of the fun. :)

So ... why are amplifiers not built as a high impedance current source?

This is an interesting read: https://www.current-drive.info/
rudyb
@atmasphere  ... thanks Ralph.  I would be fibbing if I said I understood everything you just posted, but at a high level I can appreciate a little bit better why feedback is used and what its limitations are.

Too bad our hobby is really a business.  What I mean by that contradiction is that it would be interesting to compare various types of amps (e.g., zero feedback, some feedback, solid state, tubes) in a controlled environment with the same speakers at the same time.  That is the hobby part of our musical pastime.

The business part is that, IMO, it is unfair and unrealistic for one to think that they can sit for hours on end in a brick and mortar store, take up a salesperson's time comparing amps, ... and then not to buy something.

Thanks again for the great posting on feedback.  It shows that a lot of thought and experience goes into designing and manufacturing really good audio equipment. 
The business part is that, IMO, it is unfair and unrealistic for one to think that they can sit for hours on end in a brick and mortar store, take up a salesperson's time comparing amps, ... and then not to buy something.
  • The sales people are there for that purpose.
  • And the profit margin is designed to account for that.

The alternative is to buy gear and sell it, doing the demos in one’s own home. Or just trusting the internet to provide information on what one is looking for. And that later part is bit problematic with confirmation bias.
@holmz ... I agree with your last 3 sentences.  As to your 2 bullet points, ... sure, try to spend time educating your ears, switch gear in and out, burn sales people's time.  If the sales people think your not a buyer, they will toss you. 

IME, it takes time to listen to gear, switch stuff in and out, and so forth.  And even then, unless you are switching gear in and out of your system, ... in your home, there is risk that what you think sounds good in the store may not sound so good when you get it home.      

That is why I read reviews and buy brands that I trust, like ARC.  So far, I have been lucky.  But I will never know if I could have done better because I don't sit in brick and mortar stores comparing gear.  I simply don't feel comfortable. 
Thanks @bifwynne , one problem is that I am 1000-2000 miles from most shops. But I do an appointment with one in 3-1/2 weeks.


My ARC gear has also worked fine… for many decades.