Many have independent power supplies for individual channels.
Hi Guys, Thanks for all the responses. Firstly, I do indeed have those speakers and my room has decent treatments, I do have a vaulted celing at 14ft high which certainly comes into play a little bit.
I do not tend to listen at reference levels and find myself leaning towards the Classe CA 5100, The class A bias is certainly of interest to me as my prior unit was an Arcam AVR750 which I loved and was hands down the best sounding receiver I have ever owned, its first 20 watts per channel were in Class A.
My only concern is that the Monitor Audio Platinum Pl300's are considered to require significant power to get the best from them, they are 4 ohm and recommended amplifier of 100-300w. I like the look of the krell that Auxinput suggested but he correctly reasoned that I was looking for something a little newer.
Basicallly will the Ca 5100 drive my speakers adequately? or should I continue looking at higher powered options. Thanks Again!
@erik_squires - yes, I do agree with all your points on multi-channel amps. It is, basically, a compromise to get 5 or 7 channels into a single device and still perform -somewhat- well.
The Monitor Audio speakers are 4 ohm, which will make it more difficult for an amplifier to drive. However, it doesn’t really drop down below 4 ohms like some speakers do, and most of the impedance is readily above 4 ohms:
That being said, you will probably lose some midbass punch where the impedance is almost a flat 4 ohms between 100 and 200 Hz. Also, some areas in the deep bass. The Classe amp is probably the best choice out of your 3 because of the "Class A" bias, but it is not really the best choice for the speakers.
Yes, nCore and ICE Class D amps can generate more power, but in my experience in research, the frequency response of Class D amps are typically dictated by the speakers impedance curve, meaning that the lower impedance areas will affect how powerful the Class D amp outputs. A Class D amp will probably perform very well on a speaker that is almost a flat 8ohms across the entire frequency range (much like a basic 8 ohm resistor). I don’t know about the newer Class D amps, but this is what I found with earlier Class D.
I don’t know if you are taking suggestions, but I have owned the B&K Reference 7 channel before. It’s more power than the Classe (at 200 w/ch). It has a Class A pre-driver and good power supply. The amp had really good power and volume and it was very sweet sounding, but I felt that the sound was too warm for me. At the time, I was running a Bryston SP2 Class A processor, so it was too much Class A in the audio path for me, but I think it could work out for you if you want to consider it.
Otherwise, another suggestion is to start buying up used Emotiva XPA-1L monoblock amps and run them in the Class A mode (30 watts). They are typically less than $400 each used, so it is in your budget. The only problem is supplying a separate outlet (or heavy power strip) for each amp. You need space for 5-7 individual amps and they do get hot in Class A - so you will need a good 3" space above for heat ventilation.
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.