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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.
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.
I still say the NC-500’s are much better than you think.
I’d put the latest under $2000 class D up against anything at any cost from any era.
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.
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.
Electromagnetic interferenceThe 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.
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.
Re: the OP "Are we on the verge of a SS revolution???"The answer is no. The Revolution has already happened.
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 SMPSDevialet 400 Expert Pro:THD+N : 0,00025% (440W / 6Ω)THD : 0,0001% (10W / 6Ω)Signal-to-Noise ratio: 133dB
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.pdfPS Audio has been getting some great reviews for their Icepower amps.http://www.10audio.com/psaud_stellar_s300.htmhttps://www.stereophile.com/content/ps-audio-stellar-m700-monoblock-power-amplifierhttps://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.
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