Class D is just Dandy!

Guys,

You know I was just thinking about something. If the current crop of digital amps had appeared in the 1980's I think they would have pretty much ended the solid state / linear amplifier market.

The SS amps at the time were, by and large, full of compromises, and consumers were hungry for all things digital.

This did not happen however, the digital amps of the 1990's weren't nearly as good as they are now, and solid state amplifiers also continued to advance to where they are today.

Still fun to think about. :)

Best,


E

The 60’s 70’s 80’s were the change over from germanium transistors to early silicon transistors, and the amps around at that time were ? to say the least. A good tube was better to own still. But the silicon transistor has advanced, so to circuit design.

I’m still waiting for the transistor that will take Class-D to where it will eventually get to in the rankings, Technics are using a super transistor (not available for everyone) for their SE-R1 Class-D poweramp (special order only), but it’s a $20k-$30k amp, it shows what’s ahead in the future for Class-D

http://www.technics.com/us/products/r1/se-r1.html

Stereophile listens. Technics SE-R1 Stereo Power Amplifier
"This amplifier delivered some of the best reproduced sound at CES 2017
The broad and deep soundstage, imaging, upper midrange detail, and bass extension were thrilling during the system’s rendition of "Lord, make me an instrument of thy peace" and "Pie Jesu."

Digital Trends Listen: Technics SE-R1 Stereo Power Amplifier
" Not only are we hearing things we’d never heard before, we’re hearing it in a way we’ve never heard it before. A music system that sounds like a live performance is a tough goal to attain, but Technics’ flagship nails it.

This is all due to the higher switching frequency (double of what's around now)  of these special transistors.

Cheers George

Interesting, @georgehifi re garding transistor manufacturing.

In 1976 Dr. Leach introduced his paper, Build a low TIM amplifier which transformed, if not codified, what would be linear amplifier design for the next 3 decades.

Also 80's were flirting with MOSFETs that promised to behave more like tubes. High input impedance, more linearity, blah blah blah. and some worked out, some worked out some of the time. :) I think James Bonjiorno (spelling?) and Sumo in general were among the early names that were associated with this. But we digress.

Well, there is always some technology around the corner, some new way of winding a transformer that promises never-before heard of improvements. 99% of the time, these changes don't pass the test of time, and are forgotten by their own inventors, or fail to make enough of an impression to be adopted by others. There are also a number of amplifiers who end up being door stops once the manufacturer of the super-special magic transistor stops making them.  << sigh >>

Remember Halcro with their super low distortion, universal accolades? It went under, came back... and now who knows.

I guess my point is, we can always look forward to new things, but we can't let that stop us from enjoying what we can get now. :)

Best,

E

@georgehifi

Your link just reminded me of something. One thing I really like the Japanese manufacturers for is power meters. Yamaha (professional), Hitachi, Technics, early Onkyo. Gorgeous analog meters in the 1980’s. I’m very happy to see some of this coming back, even if it is in gear I can’t afford. :)

Interesting info on the Technics SE-R1 amplifier from @georgehifi

One thing I thought was particularly interesting (and a lot of work) was the Load Adaptive Phase Calibration.

All digital amps must go through a low pass filter at the output. This may cause some variability in the high end response based on many things. Modern digital amps with easy to drive speakers should not suffer this very much (especially if they use feedback at the output, shhhhh!)

The SE-R1 takes on the approach of measuring and directly compensating for this at the input instead of using feedback.

This is a LOT of number crunching to put into an amp. Cool ideas for sure.