[THROWBACK]

I have ordered Mike's new Icepower 1200AS2 Class D SS amp (Lot 4; Standard) as a potential replacement for my Atmasphere M-1s (175 watts).

I am encouraged to think that might be possible because after a lifetime of "tubes-rule," I switched out a very fine Audio Note tube preamp for the even finer DSA (Dynamic Sound Associates) Phono II phono preamp and DSA Pre 1 preamp, both SS units. The increase in clarity and "aliveness" without a trace of the hardness/brightness/sterility I formerly associated with SS still continues to amaze me. I have almost holographic, enveloping sound, and an "ease" of presentation that is difficult to describe and impossible to measure.

But there is a problem.  The Atma's, being OTLs, do not like low-impedance speakers. I had to rewire my magnificent GR Research LS-9s (OB version) from their stock series/parallel configuration to a more series configuration to raise the impedance seen by the amps. The result is that my current system is the best I have ever heard in my home (and in anyone else's, for that matter). It may not be fair to stick Mike's amps back into my system without changing the wiring back to the way Danny Ritchie designed it. I have tried other SS amps without restoring the wiring to stock, and much of the magic was lost. Going back to the original config, however is a real pain, and I'm not sure I am willing to do that. I'm hoping Mike's amp will not need that.

So why am I messing around with Mike's amp? Well, I'm a long.-time audiophile with (I believe) an open mind. I tried Class D amps 10 years ago with my (then) Sound Lab ESLs and the sound wasn't horrible (not bad, actually, but . . . ). The M-1s require a total of 38 tubes. Reasons good and bad, maybe. Anyway, I'm willing to give it a shot.

BTW, I listen almost exclusively to classical music on vinyl. But I might be willing to try Mike's new DAC setup if things go well with the amps.

[Photon46]

I have ordered Mike's new Icepower 1200AS2 Class D SS amp (Lot 4; Standard) as a potential replacement for my Atmasphere M-1s (175 watts).

I am encouraged to think that might be possible because after a lifetime of "tubes-rule," I switched out a very fine Audio Note tube preamp for the even finer DSA (Dynamic Sound Associates) Phono II phono preamp and DSA Pre 1 preamp, both SS units. The increase in clarity and "aliveness" without a trace of the hardness/brightness/sterility I formerly associated with SS still continues to amaze me. I have almost holographic, enveloping sound, and an "ease" of presentation that is difficult to describe and impossible to measure.

But there is a problem.  The Atma's, being OTLs, do not like low-impedance speakers. I had to rewire my magnificent GR Research LS-9s (OB version) from their stock series/parallel configuration to a more series configuration to raise the impedance seen by the amps. The result is that my current system is the best I have ever heard in my home (and in anyone else's, for that matter). It may not be fair to stick Mike's amps back into my system without changing the wiring back to the way Danny Ritchie designed it. I have tried other SS amps without restoring the wiring to stock, and much of the magic was lost. Going back to the original config, however is a real pain, and I'm not sure I am willing to do that. I'm hoping Mike's amp will not need that.

So why am I messing around with Mike's amp? Well, I'm a long.-time audiophile with (I believe) an open mind. I tried Class D amps 10 years ago with my (then) Sound Lab ESLs and the sound wasn't horrible (not bad, actually, but . . . ). The M-1s require a total of 38 tubes. Reasons good and bad, maybe. Anyway, I'm willing to give it a shot.

BTW, I listen almost exclusively to classical music on vinyl. But I might be willing to try Mike's new DAC setup if things go well with the amps.

I look forward to your impressions. DSA is excellent, some of the best sounding components I've heard.

[paul79]

There’s far more specs on that datasheet than I can find on the Sansui.

Yep. Sure are more specification listings for all parts of the amp. But the actual amplifier performance specs are a bit lacking I think. Ya, I see specs for the power supply, etc, but the actual amp performance, I see less. Since they were going for page count on the specs, why not list the rest of them?

I am not picking on the amps you are speaking of. I have heard the NC500's in their best form IMO, and did walk away impressed at the level they played at vs. my expectations. That is why I would like to hear a pair of your amps to hear the latest Ncore tech at a more reachable price point. My only problem with the NC500 based amps were they got a bit lost on very complex music. They delineated well, but not as good as I would like them to, and have heard other amps do.

[2bigears]

  this great hobby is about sound/value ratio.  If a 2K dig can do what a 60k VAC can do ,,,, I'm ALL IN .   Where the hell do I sign.  I really need a new amp and pre,,,,,ha.  Really really ,,,,

[bavmike]

Yep. Sure are more specification listings for all parts of the amp. But the actual amplifier performance specs are a bit lacking I think. Ya, I see specs for the power supply, etc, but the actual amp performance, I see less. Since they were going for page count on the specs, why not list the rest of them?

I am not picking on the amps you are speaking of. I have heard the NC500's in their best form IMO, and did walk away impressed at the level they played at vs. my expectations. That is why I would like to hear a pair of your amps to hear the latest Ncore tech at a more reachable price point. My only problem with the NC500 based amps were they got a bit lost on very complex music. They delineated well, but not as good as I would like them to and have heard other amps do.

I still say the NC-500’s are much better than you think. But of course to make them top level the cost is much more than is feasible to make a marketable product from them. However just be aware that the shortcomings in your setup are from the input buffer and power supply. Not the class D end.

[paul79]

I still say the NC-500’s are much better than you think.

I don't. I have been doing this for a long time, and consider myself a very trained listener. The fact that they did as good as they did vs. my expectations based on earlier Class D designs, is impressive to me. Seemingly questioning my credibility is only good form, and I expect nothing less. However I don't know how or even know if my explanation of myself and experience would be viable in expressing my credibility. I have never been one to over qualify.

I can say that I fix things from all audio eras, and listen to these things on a regular basis in a dedicated purpose built audio room. Maybe the properly restored BA-F1 is better than you think it is? It is my current reference, and has yet to be bettered. I can name a few other amps from the 70's and some newer amps that I have had the pleasure to try and or afford that get close sonically, but none better.

I’d put the latest under $2000 class D up against anything at any cost from any era.

This is exactly how I feel about my Sansui, and it only weighs 40lbs 

I agree, to a degree, about the supply and input buffers being a possible shortcoming. The supply is the most important I think. The input stages are all pretty transparent in these Class D amps for the most part. Even some of the ones using very good off the shelf opamps.

The power supply matters BIG time for these digital amps, and switch mode is possibly the best way to get the best performance out of Class D designs from a cost standpoint.

[Wind Chaser]

The power supply matters BIG time for these digital amps, and switch mode is possibly the best way to get the best performance out of Class D designs from a cost standpoint.

I think that is a bit of a generalization; there are always exceptions to the rule. For all the good things people have said about Astron regulated power supplies, I found I much preferred an SMPS with a isolation transformer in front of it, and even more so with a DAC. As always, YMMV.

[Archguy]

Well,  I read the entire thread.  Most of it was entertaining.

Re: the OP "Are we on the verge of a SS revolution???"

The answer is no.  The Revolution has already happened.

We're just futzing with the details now. Regards

[maty]

For all the good things people have said about Astron regulated power supplies, I found I much preferred an SMPS with a isolation transformer in front of it, and even more so with a DAC. As always, YMMV.

Interesting.

What do you think about RF/EMI filters with class D amps? Or RF ferrites.

My old Panasonic TV uses plasma technology (I LOVE que quality image). The plasma technology is ultrafast, much more than class D amplifiers. I tried everything: Schaffner RF / EMI filters, Würth 150 kHz ferrites and DC & riple blockers but the image was always worse, much worse. I do not remember the sound quality with the gadgets.

Better connected directly to the wall socket.

[maty]

Talking about ferrites and filters with class D amplifiers, the Nuprime ST-10:

[Wind Chaser]

Interesting.

What do you think about RF/EMI filters with class D amps? Or RF ferrites.

My approach to audio is different from yours in that I don't need to know or even care about the technical side of things.

I judge and care about one thing only, and that is the end result of what I hear. If it sounds good, it is good.

And to be perfectly honest, I have not heard the ST-10. What's your point?

[maty]

The question is if you think that RF/EMI filters and RF ferrites are problematic with class D technology.

With class A or AB work well until the attenuation is excessive (too much filters, stages or ferrites in the chain) and causes a dynamics loss.

Class D technology has more problems with interferences than older technologies. They/we have to be more careful in design and assembly in the box.

https://en.wikipedia.org/wiki/Class-D_amplifier

Electromagnetic interference

The switching power stage generates both high dV/dt and dI/dt, which give rise to radiated emission whenever any part of the circuit is large enough to act as an antenna. In practice, this means the connecting wires and cables will be the most efficient radiators so most effort should go into preventing high-frequency signals reaching those:

* Avoid capacitive coupling from switching signals into the wiring.

* Avoid inductive coupling from various current loops in the power stage into the wiring.

* Use one unbroken ground plane and group all connectors together, in order to have a common RF reference for decoupling capacitors

* Include the equivalent series inductance of filter capacitors and the parasitic capacitance of filter inductors in the circuit model before selecting components.

* Wherever ringing is encountered, locate the inductive and capacitive parts of the resonant circuit that causes it, and use parallel RC or series RL snubbers to reduce the Q of the resonance.

* Do not make the MOSFETs switch any faster than needed to fulfil efficiency or distortion requirements. Distortion is more easily reduced using negative feedback than by speeding up switching.

[paul79]

I think that is a bit of a generalization; there are always exceptions to the rule. For all the good things people have said about Astron regulated power supplies, I found I much preferred an SMPS with a isolation transformer in front of it, and even more so with a DAC. As always, YMMV.

No. How it should have read is that it would take a serious amount of money to build a linear supply that performs better than the SMPS in the NCORE amps. This was more of a compliment in that regard. Also trying to express just how important the supply is with these amps. I also believe SMPS tech evolution is the main driving force behind these Class D amps getting better.

[Freo-1]

No. How it should have read is that it would take a serious amount of money to build a linear supply that performs better than the SMPS in the NCORE amps. This was more of a compliment in that regard. Also trying to express just how important the supply is with these amps. I also believe SMPS tech evolution is the main driving force behind these Class D amps getting better.

It's not just NCORE.  Benchmark makes excellent gear, and that includes switching power supplies.  They state that their SMPS are an improvement over linear power supplies.

https://benchmarkmedia.com/blogs/application_notes/152143111-audio-myth-switching-power-supplies-are-noisy


Check out the specs of this audio playback setup with SMPS

Devialet 400 Expert Pro:
THD+N : 0,00025% (440W / 6Ω)
THD : 0,0001% (10W / 6Ω)
Signal-to-Noise ratio: 133dB

[Early B.]

Re: the OP "Are we on the verge of a SS revolution???"

The answer is no.  The Revolution has already happened.

I agree. We're at the beginning of a revolution in high end audio where massive amps and a system of separate components are being replaced with smaller amps and integrated setups. For instance, my previous amp weighed 75 lbs. -- the current set of monos weighs about 5 pounds each. Likewise, my previous DAC weighed over 30 pounds -- the new one weighs less than 2 pounds. My system sounds far better at a much lower cost.

The next audiophile revolution will be battery-powered bluetooth speakers with integrated amps built inside of them. No power cables, no speaker cables, no interconnects, no power conditioners.... The technology doesn't need to mature to make this a reality - it's already here. The non-audiophile community has been using bluetooth speakers for many years.

[Freo-1]

Along the lines of advancement, the current availability of Digital Audio Players (DAP), and what they can do,  is remarkable.  One can get audiophile quality sound from a unit that can connect via wireless, supports streaming, can act as a digital streaming source for a home stereo, and can store one's entire music collection. 

[paul79]

It's not just NCORE.  Benchmark makes excellent gear, and that includes switching power supplies.  They state that their SMPS are an improvement over linear power supplies.

https://benchmarkmedia.com/blogs/application_notes/152143111-audio-myth-switching-power-supplies-are-noisy


Check out the specs of this audio playback setup with SMPS

Devialet 400 Expert Pro:
THD+N : 0,00025% (440W / 6Ω)
THD : 0,0001% (10W / 6Ω)
Signal-to-Noise ratio: 133dB

Semantics... Not trying to leave anyone out, just giving a for example. The Theta Class D amps are supposed to be quite good too. Have also heard that the Cherry amps are supposed to be unlike any other Class D.

[OzarkTom]

If the smaller Icepower amps sound good and Emotiva brings these out, they would be great for desktops.

http://www.sohmerassoc.com/ces_2017/emotiva/Emotiva-CES17-Emersa-010317.pdf

PS Audio has been getting some great reviews for their Icepower amps.

http://www.10audio.com/psaud_stellar_s300.htm

https://www.stereophile.com/content/ps-audio-stellar-m700-monoblock-power-amplifier

https://www.cnet.com/news/get-ready-to-upgrade-over-receiver-sound-quality-amplifier-preamp-power/

http://hifipig.com/ps-audio-stellar-gain-cell-dacpreamp-s300-stereo-power-amplifier/

Stereophile gave the S-700's a Class A award.

[FullRangeMan]

These amps you linked are nice but 200/300W is too powerful, it would be nice a 50W Class D intended to drive a single driver Fullrange with the respective price reduction.

[debjit.g]

If the smaller Icepower amps sound good and Emotiva brings these out, they would be great for desktops.

http://www.sohmerassoc.com/ces_2017/emotiva/Emotiva-CES17-Emersa-010317.pdf

PS Audio has been getting some great reviews for their Icepower amps.

http://www.10audio.com/psaud_stellar_s300.htm

https://www.stereophile.com/content/ps-audio-stellar-m700-monoblock-power-amplifier

https://www.cnet.com/news/get-ready-to-upgrade-over-receiver-sound-quality-amplifier-preamp-power/

http://hifipig.com/ps-audio-stellar-gain-cell-dacpreamp-s300-stereo-power-amplifier/

Stereophile gave the S-700's a Class A award.

S-700s are truly getting stellar reviews both from reviewers as well as end users. PS Audio is using the Class D only as the output stage, while the input stage (Analog Cell) is their proprietary design.