You've been having fun! nice.
Reminds me of myself 30 years ago, when I made my 2nd active speakers.
I used
Meridian 105 monoblocks for my two bass drivers perside, and a
Meridian 103D (D= dual PSU) stereo power amp to drive my midrange and tweeter. To complete the electronics, I designed and built a simple three way electronic crossover to feed the amps.
The amps were heavily biased into class A operation.
I made a pentagon column pair of speakers with midrange driver having an enclosure of its own at top (Kef B110).
It worked, and sounded good, It is still working at a friends house in Yorkshire!
The Sony amp uses a novel (to me) bias arrangement based on volume control setting, to alter the bias of the output stage according to how much power it assumes it needs - for what purpose? - save on electricity and heat generation!
As cute and clever that it is, I rather not! lets think about it:
- let us assume we are listening to some music with a dynamic range of 30dB (let's keep it real and easy) at an
average listening level if 95dB.
- let us assume our speakers have an efficiency of 89dB for one watt (again we keep it real)
- This means we need an
average power of 4 Watts from the amp.
- Nick Mason comes along and starts to kick his bass drum on "Run like Hell" from "the Wall" !
- momentarily we may need 120+ Watts to reproduce the transients, but the amp sees that we are on level 4 on the volume control and has adjusted the bias accordingly!
- Amp goes into class B mode on transients.
- Now when Nick hits those hi-hats hard, sound will defo. gets grainy.
When I want sound quality, I WANT sound quality! I will pay for it, in electricity bill, heat built up, equipment cost and wife's nagging!
No compromises!
My OTL tube amps burn over 400 Watts at rest EACH! while producing a max. of 50 Watts output, but on average I am on about 10 Watts per channel.
Sony's approach is cute, class AB is a useful topology, but isn't it horses for corses?
If I need 200 Watts from a moderate size amp, class AB does nicely, if I need 2000 Watts class D does nicely, but at home when I need an average of 10 Watts, only class A will do.