shtf Posted June 16, 2018 Share Posted June 16, 2018 On 6/10/2018 at 1:45 PM, Kimo said: I am considering auditioning some higher powered electronics with my Alta Audio Celesta FRM-2 monitors. They are of a nominal 4 ohm load. I am only interested in integrated amps. So far I have come up with 2 candidates. 1. Pass Labs INT 250 2. Jeff Rowland Continuum S2 I have ruled out a few brands already for various reasons: Accuphase, Ayre, Boulder, Chord, Devialet, and Musical Fidelity. Looking for suggestions and at least 200 watts per channel into 8 ohms. Market seems smaller than I had thought. I am done with heavy separates and monoblocks, though obviously the Pass isn't very easy on the back. Of the two primary choices you list, without hesitation I’d opt for the PASS Labs but only because it’s not Class D whereas the Jeff Rowland is Class D. Don’t get me wrong. I love Class D amps. Well, the musical ones anyway. I experienced an integrated high-powered Class D amp and though I thought it rather musical in some ways, I got rid of it is because I heard what seemed to be an unusual amount of audible distortions. I’m big on using superior line conditioners to cleanse / purify the noisy AC coming in from the street and I remember an experiment with some prior Class D mono-block amps each having their own dedicated line conditioner and then the added distortions received when I tried sharing just one line conditioner between the 2 mono-block amps. Anyway, I remembered that experiment when I was auditioning the integrated Class D amp. That’s when I realized 2-channel Class D does not work well in a single chassis configuration and especially not in a single-chassis integrated amp configuration. Though not digital, Class D’s high-speed switching amps will induce a digital-like bi-directional noise that, when power is shared at a single AC inlet, the bi-directional digital-like noise is also shared between the 2 channels at the common AC inlet. And with Class D, it's common for each channel has its own amplification section even though they share a common chassis. It only gets worse when that same configuration is taken to an integrated design because the pre-amp section must borrow AC from one of the 2 channels. And since the 2 channels are already sharing their bi-directional digital-like noise with each other, now the pre-amp section is also getting the bi-directional noise of both channels. So based just on the two amps you listed, I can all but guarantee you the PASS Labs int. amp stands a far greater probability of sounding more pristine, more delicate, and just more musical than the Class D int. amp by Jeff Rowland. But I’ll put in a plug for another Class D amp. About 4 years ago, I went from my $8k BMC C1 int. amp to try the Wyred-4-Sound (W4S) SX-1000 575wpc Class D mini-mono-block amps that retailed for $2400 the pair. Though not necessarily the prettiest of amps, the W4S mono-blocks are by far the most musical amps I’ve owned to date and frankly, made the BMC int. amp sound like a $100 BestBuy receiver in comparison. And that’s not to say the BMC amp was inferior. But there’s a caution with any rather high-powered amp which as with the W4S’ high-powered 575wpc provides a rather powerful and dynamic presentation. So much so that in my already quite dynamic system, it now seemed the initial attack of every musical note was in my face when using an active gain stage pre-amp. Almost like my ears were running up onto the soundstage for the initial attack of every note and then running back into the audience for the ensuing decay. Which to me is not very realistic. But when I removed the active pre-amp and just went with my digital source’s internal passive volume attenuator, it became an incredible combination because now all the music remained at the soundstage including the notes’ initial attack while my ears remain firmly planted into the audience. And though I swore numerous times I’d never go with a passive pre because of my love for dynamics, my system is actually just as dynamic as ever because of the 575wpc but now in a much more realistic sense and always with a distance between my ears and the soundstage. As it should be. Also, I’m pretty sure W4S still has a 30-day satisfaction guarantee or your money back. I should mention there is yet another potential benefit of going with very a high-powered amplification / passive volume attenuator combo which is the overall music presentation became that much more pristine and even delicate, especially in the higher frequencies. I suspect because any time an input signal is amplified new distortions are induced and/or the amplified gain stage amplifies pre-existing distortions. And a passive pre-amp eliminates this potential as well. The more I dabble with extreme forms of electrical mgmt. and extreme forms of vibration mgmt., the more I’m convinced it’s all just variations of managing mechanical energy. Or was it all just variations of managing electrical energy? No, it’s all just variations of mechanical energy. Wait. It's all just variations of managing electrical energy. -Me Link to comment
Popular Post shtf Posted March 30, 2019 Popular Post Share Posted March 30, 2019 On 6/11/2018 at 5:28 AM, MetalNuts said: I had used this before and it sounds thin but it is one of the best Class D amplifier you can get. Another thing I don't like is the polishing which will easily be stained and the manual said that it is not advisable to clean even with a light damp cloth. So it leaves me hanging of how should I clean it (I have the habit of cleaning my equipment every week). Once again, it is your cute avatar that attracted me to your posts here. Until I start getting the dry heaves, then it drives me away. I agree with you about the McIntosh gear. As for the Jeff Rowland or any Class D integrated amp for that matter, I'd suggest steering clear of any Class D integrated amps or for that matter any Class D stereo amps. Don't get me wrong as I love some Class D amps but even then only the mono-block versions. The reason being that Class D, though not digital, will induce a bi-directional digital-like noise (just like all digital gear) due presumably to their high-speed switching modules. Hence, Class D stereo amps (1 board per channel sharing the same chassis and same IEC inlet) will share each channel's bi-directional digital-like noise with the other channel at the IEC inlet. With regard to Class D integrated amps, it gets much worse since the 2-channels are already sharing their bi-directional digital-like noise with each other inducing distortions into the other's channel, since the pre-amp section must borrow AC power from 1 of the 2 channels, the pre-amp section is now getting a double dose of this digital-like noise. Moreover, that double-dose noise is then being amplified via the pre-amp's gain stage. There's only one way I'm aware of to get around any of this digital-like bi-directional noise with Class D amps and that's mono-blocks only with superior dedicated bi-directional filtering line conditioners. That's the only way to get the very most out of Class D and if that can be done, in some cases the results are quite musical. As for the OP, if Class D is on their list of contenders and they should, then Class D mono-blocks plus superior passive and bi-directional filtering line conditioners is the only work around. And if the Class D mono-blocks amps are high-powered, then a passive volume attenuator at the source is all that's necessary to produce a potentially very musical and still quite dynamic playback presentation. Matias and MetalNuts 1 1 The more I dabble with extreme forms of electrical mgmt. and extreme forms of vibration mgmt., the more I’m convinced it’s all just variations of managing mechanical energy. Or was it all just variations of managing electrical energy? No, it’s all just variations of mechanical energy. Wait. It's all just variations of managing electrical energy. -Me Link to comment
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