Originally Posted by sprintright
Tell me about the SC-68. I have Magnepan MMG up front. with Oppo 93
well, I'm a maggie user for many years & have used the Ice amp based SC-09 and the SC-68. not sure how "warm" is "warm" but I think the sound is consistent with my former Pioneer flagships with class A/B amps, the 49txi & 59txi. there's 1 or 2 who disagree and have stayed with the 59txi even tho it's at least 8 yrs old now IIRC. I also have an Innersound amp made by Coda that's class A/B and very hi powered amp made to drive e-stats.
Emotiva: this could end up being controversial
edit - I removed most of my comments on the XPA5. It just isn't relevant to your question and all it does is foment arguments
I'm not dissing the XPA-5 per se, is an OK amp for its price. but it would not find a place in my setup. the XPA-1, 2, and XPR-5 are a different story. I fully accept that those
meet & maintain their rated power
I think you know where I'm coming from.
the SC-68 should hold its rated power up to 5 channels, then will naturally drop. keep in mind it has a 810 watt power supply, but that is class D so being 80-90% efficient, it should have the reserve to be very dynamic. but in comparison with the Denon 4520, a german reviewer who bench tested both, showed the Denon dropping drastically off to only 35 watts per ch at 7 channels. the limits of the power supply start to come into play.
H-K: I haven't had good luck with the 2 Harmon-Kardon products I owned a long time ago. both receivers had quality problems, one required lengthy stays in the repair shop & one was DOA! so I've had no interest in 40 years to own another one. I can't give you a comparison
supposedly H-K is noted for conservative rated amps, a "warm" sound and having a form of Logic 7 surround processing which many Lexicon owners highly valued
there have been a number of maggie owners using the class D SC models over the past 5 years but I can't recall names.
for the record, I have 3.6's, CC3 & MC1 for surrounds. the 3.6's are on the ext amp because they do sound their best and best dynamics the more power you feed them. but I have driven them with the SC-09 & tried out the SC-68 on them and was pleased with the sound. the SC-68 held up very well
I don't think the SC-68 will have any trouble powering your MMG''s & be able to give you decent dynamic peaks. but you'll be using a sub anyway so I'd definitely set your MMG's as small, probably use 80 hz crossover.
if you were happy with the power of the H-K's by themselves, you should be with the 68's power.
what you might be noticing as "warm" may not be the amp but how H-K does room EQ. in this, you'll have to draw your own conclusion based on listening to a SC-68 with Pioneer's MCACC room EQ system. I've been happy with it with maggies for going on 10 years now. and if you'd like a bit extra warmth, you can tweak the 125, 250 hz bands to taste. I always felt my sound had body in the mid-bass, low mid-range areas (warmth) and didn't sound "lean". some attribute an edge to hi-freqs to class D design but I have no idea. I can say that all class D amps have the characteristic that distortion starts to rise in the high freqs > about 10-15K, but it's still well within low levels & is a gentle rise until you reach the clipping point. bench tests on the SC-57, the 1st with Pioneer's new class D design, actually showed lower & flatter distortion levels than the previous Icepower amps they used. the switching power supply in the new design is pulsed at about 500-600 Khz while the Ice amps were about 50-60Khz. just like oversampling a digital recording, faster power pulsing probably does = smoother sound.
and this is very subjective
but to my ears, the SC-68 did seem to have just a bit less "edge" to the sound than the Ice amps in the SC-09 did, fuller, more rounded sounding. it reminded me of my class A/B Innersound amp
but I think the difference in how Air Studios tuned each design plays a role. all this is definitely not scientific or objectivist
just an opinion, consider it like all others....fwiw, ymmv
there are a number of MUG forum members who have used the big maggies with class D amps from D-Sonics, Wyred4Sound, Gilmore Raptors. but these are more powerful amps, being based on the 250, 500, & even 1000 watt Ice amps: http://www.integracoustics.com/MUG/MUG/
my best advice is go take a listen. also you may want to PM forum member purdyd. he also uses maggies with his SC-57 and is also happy with his sound.Edited by ss9001 - 1/25/13 at 2:19pm