Class D is just Dandy!


I thought it was time we had a pro- Class D thread. There's plenty of threads about comparisons, or detractors of Class D.

That's fine, you don't have to like Class D amps, and if you don't please go participate on one of those threads.

For those of us who are very happy and excited about having musical, capable amps that we can afford to keep on 24/7 and don't require large spaces to put them in, this thread is for you.

Please share your experiences with class D amps!
erik_squires
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.
EPC (small company) Alex Lidow is the inventor of this new GaN-FET transistor Technics uses, and he happens to be the inventor of the Mosfet/Hexfet all those years ago I believe.

Cheers George

@georgehifi

Very interesting! :)

Hexfets..... I seem to remember ... was it Toshiba that invested heavily in them for a while?

Best,

E