Class D is just Dandy!

@georgehifi

Very interesting! :)

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

Best,

E

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

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.

@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, @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

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

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

I have had Nuforce Reference 9 V2, the V3Se and Now Nuforce/Nuprime Reference 20 monos. They have bested in my opinion all Class A and A/B designs that I have heard with high end Pass Labs coming closest to reflecting the beauty of music. Also Nuforce best of the 5 Class D amps that I have heard which were all great in the bass but not as liquid and natural in mids and highs. Plus I do love the size, weight (which allows me to easily take them to other's homes and compare to their amps or ship for mods) and continuous on because of low power use. Have found class D to be sensitive to power cords, electronic and mechanical isolation, long break in and warm up. I agree with many that they are especially nice paired with a tubed preamp, in my case Ayon.

Erik,
Great informative post, with accurate descriptions of the objective differences of the sound of Class D vs. other fine amps.   You nailed it.  Class D amps do not presently have the euphonic sound of the best Class A solid state or tube amps, but I think they are exceeding accurate, so one must pick their poison, so to speak.  I dig "green" gear that needs minute amounts of electricity to make my speakers sing and doesn't heat up my listening room in the blistering hot CA summers which was always the curse of my many tube amps, running a half dozen KT88's hard.  To my ears, a tube preamp and solid state amp, including Class D amps, is a match made in audio heaven.  Cheers.     

Hi randy-11,

If you mean the multi-channel amps with Hypex/nCore modules, YES THEY DO! 

I would just be sure to listen first. I have heard a couple of modern NAD gear and I didn't like it. This is a brand I really encourage you to listen / try out before committing.

Best,


E

Hi @roxy54

You know, I probably heard the same Class A amps @whitestix heard in the Bay Area and I have to concur. I re-iterate, blindfolded and level matched I don’t think I could tell them apart from the Parasound A23’s. Both are excellent, modern sounding amps via my reference speakers.

Negatives?
The ICEPower 250 ASP modules are in no way euphonic. They lack the utter calmness and dark backgrounds of the very best Ayre or Arcam systems. They lack the juiciness if not excessive boldness of the best big Conrad Johnson tube amps.

Despite all of this, they are very very engaging and when the music and sources are right just as compelling to listen to as the best amplifiers I have heard.

Unlike the worst SS amps, they also don’t sound thin, compressed, underpowered or grainy at all. I just listened to Trombone Shorty’s latest tracks via Jazz FM 91 and man, freaking awesome playback. Absolutely nothing was missing nor called attention to itself in terms of the amplifier.

Best,


E

Gents,
I had a pal construct a Class D amp in a nice wood cabinet that set me back the princely sum for $125.  It won a blind comparison against a pricey Class A ss amp at a gathering of the Bay Area Audio Society.  I initially felt the sound of the amp was rather dry sounding compared to my tube amps, but upon further listening, I conclude that it has a very neutral sonic signature.  However, this 125 wpc amp, paired with a Don Sachs 6SN7-based tube preamp, is a wonderful combination.  It drives my Dali Zensor 3 speakers with ease with great detail and extension.

I believe Class D amps are clearly the wave of the future.  They run so cool and efficiently and the new wave of designs I suspect will be able to mimic attributes of the sound of tube gear that so many of us like.  

the nads look interesting

I have a Class D Ampeg bass amp. It's tiny for 350 watts. Thought I'd toss that one in there, and I'm hoping it counts.

Happy to see a thread "celebrating" this technology.  I have a Taranis Class D power amp from Merrill Audio.   Apart from the sheer power this thing supplies, I'm very impressed with the quality of bass from Totem Forests when driven by it. I think outstanding bass quality might well be a hallmark of Class D design.  The Totems' bass is impressive to begin with - especially considering their driver size, but the Taranis takes them to another level.  Bass is deeper and fuller than with either the solid state integrated I was using (Hegel H-200) or my EL-34/78WPC tube mono blocks.  The Taranis makes using a subwoofer with the Forests truly unnecessary for most (most) recorded material.  I also like the fact Merrill has produced a balanced design.  Having recently brought a Schiit Freya pre-amp into the system, I can now run balanced outputs from CDP & DAC into the Freya and from Freya into the Taranis.  Balanced, to my ear, is associated with a less fatiguing and cleaner sound.  The Taranis certainly allows long listening sessions; I don't experience listener fatigue using it.  Add to that cool running and no reliability issues, so far.  I did attempt a review of it here on A'gon. shortly after buying it.  Thanks very much to Audiogon member D. Patterson for getting me started thinking about Class D (he's been something of an audio mentor - intentionally or not!).  Thanks also to Guidocorona for pointing me towards the Taranis and Merrill Audio.  

I always liked your handle, islandmandan.  Maybe the noise you are hearing is the tropical breeze blowing though the palm trees.  Please don't spoil it for me if you are on Long or Staten Island.
George

I use Class D Audio amps I built from kits. My old Adcom 5 channel bit the dust, and I needed a low cost replacement. I made a three channel amp using two modules, sharing a common power supply. One module is in stereo mode for the surround speakers. The other is bridged to mono, for 500 Watts to the center.

I like this arrangement so much, I built another amp, using two modules bridged to mono, for 500 Wpc for my main speakers. Sounds ridiculously good, especially for the cost. I use this amp for 90% of my listening, an SET 300B for the remainder. They both sound good in my situation, though the modules that are bridged tend to be a bit noisy. They sound so good, I really don't mind.

Regards,
Dan

Purchased a Rogue Sphinx from Audio Connection a few monthes back to use with my Green Mountain Europa's. Very happy with the sound

Greg,

Good to hear. TBH I've only heard B&W speakers with Krell amps, and that combination never made me reach for my wallet.

Interesting you find the ICEPower modules working so well for you. :)

Best,


E

I'm running one of the original IcePower-based seven channel amps from D-Sonic.  They run two Bowers & Wilkins Nautilus 800s each driven with two 1000ASP modules (biamped) and a pair of Nautilus 803's plus a center.

The amp absolutely dominates the 800s in this configuration and sound better than with any other amplification that I've heard them through.  Of course I've not heard them through $45,000 monos :)

Greg

  I am on my second amp from the digital amp company.  They don't get much fanfare here on audiogon but the cherry plus amp is awesome.  Very clear and just a tad bit warm and laid back, plus it is very powerful.  Very happy with mine

I should say that in the mid-80’s I did get to listen to early Class D amplifier from one of our vendors. It was not then up to snuff, especially not with metal dome compression drivers. :)

Best,

E

Hy Roxy,

I never did. My experience in the pro world was in motion picture auditoriums. At the time my employer bought Hafler amplifier modules, attached their own supplies, and their own surround processing. We probably kept Hafler in business a lot longer than they would have been otherwise. I understand they have come back though.

My day job is esoteric related to IT.

My current set-up uses custom loudspeakers driven by ICEPower 250ASP modules. I did a lot of listening and comparing them to Parasound Halo A23 amplifiers, which while small, are fabulous performers. I rate the two as equivalent in sound quality.

Best,

E