plga, I just checked Nords site. It would cost > $2.2k for the Mk IIs. I don't mind the wait, but I can get a pair of AA monos for ~ $1500 (MSRP $3990) and that extra $700 I would need to spend now is a big stretch. I realize that the perceived value in the new amps could pay off at some later date, and that when I sell the AAs, they might further drop in value when I decide to sell
The Future of Audio Amplification
I have recently paired an Audio Research DS225 Class D amplifier with an Audio Research tube preamplifier (SP8 mkii). I cannot believe how wonderful and lifelike my music sounds. The DS225 replaced an Audio Research SD135 Class AB amplifier. Perhaps the SD135 is just not as good as some of the better quality amps that are out there, but it got me thinking that amazingly wonderful sonance can be achieved with a tubed pre and Class D amp. I have a hunch that as more people experience this combination, it will likely catch on and become the future path of many, if not most audiophile systems. It is interesting that Audio Research has been at the forefront of this development.
- ...
- 390 posts total
Well, thats something you have to think and decide on your own. It will be difficult for me to sell my previous 300B valve amp because its an expensive one and in my country (Argentina) there arent many people that can buy it, but I dont care much because, even selling it at a very low price, I should recover the money I spent on the Nord. And Im not even considering the replacement valves I have in stock and I also have to sell. But everything is now less importante considering that I have now a much better sound, less heat, less energy consumption, a smaller and lighter amp and I wont have to spend on valves ever again. Is up to you and your circumstances. |
It is always best to have dual mono......so here is a link to a review from a person that owned the mono Nord one up amps (with the Sonic Imagery op amps) and then bought two stereo amps with the IceEdge 1200AS2 modules in them and then ran each amp as a mono block.....so now we have a fair comparison (fully mono in each case). He says which one he prefers. https://www.audiocircle.com/index.php?topic=154910.80 Post #97 And this is with stock IceEdge modules implemented in a normal way. Imagine how much better it could sound with tweaked modules and tweaked execution.......stay tuned......coming soon. |
Dead time is part of the design of the amp, not something that arises from its ’harmonic structure’.Haven’t found a digital which can compete.Most digital are to clean for my ear.Sterile with no decaying harmonic structure, creating too much dead time, are the words I believe you should be using. Judging by the measurements I keep seeing, great class D amps still haven’t arrived. Most of them have issues with ringing. All of them have ultrasonic noise that sits on the outputs like standing DC. Upwards of .8 volts of noise!?!?!? That’s hifi, is it? A 1kHz sinewave looks horrible through those things. For all intents and purposes, it’s made entirely out of high frequency noise.@kosst_amojan Actually a 1KHz since wave looks good on most of them, without any noise. The ultrasonic noise to which you refer is the residual and is itself a low distortion sine wave at the switching frequency. Show me where it is stated that the Merrill uses higher than 500K for its switching frequency. In fact, Merrill stated (on this site) that higher frequencies for switching were harder to do. I hope Mr. Merrill steps in here and clears this up. What he seems to claim is that the zero dead time using GaNs plus his zero feedback circuit are what makes the great sound. The advantage of such high performance output devices is that they allow one to build a circuit that has no dead time circuitry in it. This means the circuit is a **lot** simpler! Of course, there is always some shoot-through current, so by going with a lower switching frequency a lot of consequences of that are avoided- one can use a slightly larger heatsink and the shoot-through heating is controlled. But the advantage of reduced distortion via no dead time is profound. So this should be a very nice sounding amplifier. Go to Stereophile and look at the last 5 or 6 class D amps they’ve measured. Unless JA applies a low pass filter on the AP the output signals look horrendous.@kosst_amojan I did and found the review at the link below. I think you may have misinterpreted something in JA’s measurement comments. The filter to which you refer above has to be there because all class D amps have a residual sine wave component, which has to be filtered in order to prevent the analyzer from having difficulty; in JA’s words: As class-D amplifiers produce RF noise that could drive my analyzer’s input circuitry into slew-rate limiting, between the test load and the analyzer I inserted Audio Precision’s auxiliary AUX-0025 passive low-pass filter, which eliminates noise above 200kHz.Note the cutoff frequency of the filter- 200KHz, and why it needs to be used. Nowhere in this article does JA say or imply anything that you suggest above. He seems to think the waveforms look pretty good. https://www.stereophile.com/content/mytek-brooklyn-amp-power-amplifier-measurements You need to understand better, it’s not the switching frequency "so much" but the "output filtering" needed to get rid of it that ’s problem, which gives phase shift problems right down to 3-5khz (the mids and highs of the audio band).@georgehifi This statement is incorrect. Many such filters are 12db, but if only 6 db, that is where you use the rule of thumb that the phase effects extend to 1/10th the cutoff frequency. In the case you state above that would be 45KHz, not anywhere in the audio passband! If 12db, the effects are more constrained; IOW 6 db is a worst-case scenario. |
which has to be filtered in order to prevent the analyzer from having difficulty; in JA’s words:This is just pure BS and you have been sucked in by those words "your just echoing Stereophiles words" that are advertiser driven, and anyone can see it. And I think you know that, as you don’t want your Class-D to look bad when a 1k square wave is put through it. As no such AP filter was used at Stereophile before, when all Class-D were measured with the same analyzers. And it showed just how bad what was coming out of Class-D’s. Also when the AP filter was introduced, Stereophile use to give the wave form shots with and without the filter. And then later mysteriously only with the filter, probably because of manufacturers complaints how bad it looked without filter. So one can see it was just the ugliness of the wave form without the filter, that potential customers didn’t like seeing, and this effects sales, and advertising. Just like ricevs (Tweak Audio) you are both protecting your soon to be released Class-D amps, and just ricevs you do/say anything not to tarnish it’s launch. Again a blind man can see it. |
- 390 posts total