Need Advice on Multi-channel Amp Choices.

One other question, are those speakers one's y ou own or are thinking about?

Do you have good room treatment? Especially important with subs.

I am usually suspicious of multi-channel amps, especially if linear. If I had to go with a single multichannel amplifier the NAD M27 is one of the few I'd be serious about.

Multichannel amps are usually compromised some way. From limited power outputs, inter-channel crosstalk, heat generation and disspation and yes, the shared power supplies.

Especially if we are talking 7 channel outputs. Otherwise, you get into really mosntrous amps like the Theta Dreadnaughts. Physically huge beasts.

The NAD with the nCore amplifier modules is one of the very few I would not be worried about. It’s still limited to 180W continuous, but that’s all 7 channels driven, or 1,200 W continuous. That’s a lot of power in a single relatively small 7 channel chassis and I could fit it on one of my existing shelves.  It also does around 600W peaks. That's pretty awesome and useful in a home theater.

By the way I’m not a huge NAD fanboy. I really like nCore, and ICEPower though. The NAD DACs I’ve heard were not to my taste, but damn, I like the look and modular concept of their processors. :)

Arcam is also nice, but not a very good track record on upgrades.

Best,


Erik

I found your comments about frequency response interesting. That would imply that they have high output impedance (or low damping factor) which they do not, by themselves have. Tube amps of course tend to behave this way. If you can point me to any measurements for the ICEPower or nCore amps which do this I’d love to check them out.

Most amps reduce DF (increase output impedance) as F increases, but older class-D amps pretty bad in this respect. If memory serves though, nCore and the later generation ICEPower units solved this quite well.

In solid state amps improving (reducing) output impedance is usually a matter of feedback, and in D class amps where the feedback is applied.

If memory serves, the feedback on the nCore is at the output stage, instead of before, a good thing. They have ridiculously low output impedance as a result. Any "frequency tracking" of the speaker impedance is not due to the nCore design.

I use bare ICEPower 250ASP based monoblocks to drive 4 Ohm speakers (min impedance 4 Ohms through mid bass) and they do superbly. The ICEPower amps replaced a pair of Parasound A23s, which are fairly well biased into Class-A for the first 30 or 40 watts. I could not hear a difference, so I completely converted. I was running the Parasounds in a 4.0 HT configuration, so 1 amp was left, 1 amp was right.

Best,


Erik

I’m not sure about the nCore, but as for the ICEPower units, I would say that’s true, they really don't add anything to the signal so if you need warmth or liquidity added these are b. .... however....

Using my current reference speakers I could not tell a musical difference between an ICEPower 250ASP and Parasound A23. The A23 is often described as warm, and my system is as well by listeners who do not kwow what the amps are.  My sources are a Mytek Brooklyn DAC feeding a Parasound P7. I could see myself trying out a tube preamp here or there to add some liquidity to the top and magic to the midrange, but the sound is most definitely not lean or soul-sucking like I have heard some mass produced processors to sound. I’m pretty happy with what I have, but tubes are tempting. :)  I have heard from a couple of users who attempted to use the ICEPower amps directly from PC sources, that did not go very well for them, I'm afraid. :D

Certainly for movies I lack nothing. Engagement, dynamic range, dialog intelligibility and transparency across the audible range are excellent.

Some of this may have to do with having relatively easy to drive speakers. Min 4 Ohms, and 8-10 in the treble, where I have read at least 1 complaint of the ICEPower units with Maggies. The ribbon tweeter in Maggies becomes inductive, while my speakers use an AMT which remains resistive from the crossover frequency upwards. It may very well be that there is some speaker dependent behavior. On the other hand, the Monitor Audio speakers are fairly straightforward to drive and nCore have an even lower output impedance than the ICEPower units.

My surrounds are even easier to drive, remaining around 8 Ohms through the midbass, and min 6 elsewhere.

So, to sum it up, if you have reasonably normal speakers without reactive tweeters and your sources have all you need in terms of warmth, tone, etc. I think the current batch of Class-D amps is an excellent choice, and the NAD 7 channel nCore a fabulous bargain.

Best,


Erik

Glad you got something you can appreciate happily for many years! :-)

Thanks for letting me play.

Best,

Erik