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SS Amps for C4 Signature II's

OK, I’m curious about amps.

I have a set of C4 Signature II's that are running with ODYSSEY KISMETS and seem to sound pretty darn good. But, they aren't the be all to end all amps, and they never were meant to be. A good sounding "value", well yes. I have no major complaints on their sound for the price. So, lets not pick on them but look at what might be an upgrade for these speakers. Dragging amps home to audition is a physical exercise in and of itself with 75 pound and heavier weights I'm seeing!

I have just a few amps that seem to be very compelling for different reasons and I’d like some viewpoints from all of you that have been here, done that, and especially C4 users. C4’s can be an odd load at the low-end.

1.0 The first thing is CLASS A verses A/B. The image stability of CLASS A amps is derived from the voltage rails being sag proof (or more so) than class A/B since the are charged up all the time. Yep, that eats power, too. Still, this is an advantage if you pick the right amp.
2.0 A/B amps come in two flavors, high bias amps like an old McCormack DNA-225 (it gets plenty hot when running!) or a lower bias unit like my ODYSSEY KISMETS that refuse to even get warm. The “hybrid” high bias amps that are around (PASS LABS as an example) can run CLASS A pretty high (up to 40 watts in the case of a X350.5). Is that enough to capture the CLASS A “flavor” and A/B efficiency?
3.0 Weight. Man, how do you move your stuff? Some amps are frighteningly heavy making a dual MONO set-up seem logical, but even more expensive. I may get the sound, but the weight can drag you down. Yes, weight is part of the deal in a good power supply, which means get the power you need.
4.0 I HAVE to be able to listen to them before I buy. I don’t need “more” of the amp I have now, worse or the same general sound, but better. So in-house audition is a must. I can’t easily get the PASS or ANTHEM products making auditions and service a pain. But, if it’s worth it, I can try. I can get BOULDER products but they are WAY high priced.
5.0 I am using a PASS LABS XP-10 pre amplifier so I have full balanced or RCA outs.
6.0 Is it just me, or are the specs on these units hard to come by? VA transformer ratings, CAP values in the power supply ETC? Not that this is all there is, but it helps.

So considering those points, and if I’m seeing all this right, we can sort of claw through some of this on paper.

My first choice, again, on paper; Plinius SA-103.
I have heard the Plinius on Theil CS2.7’s, and it imaged VERY well. Can’t comment on the musical balance on my speakers, though.
All CLASS A capability but can run A/B with the flick of a switch so I can listen to the radio with A/B!
Seems to be a solid design with good sonic ratings.
Plenty of power (125 watts / 220 watts) for the volumes I listen to (83 dB SPL average where I sit 15 feet away).
I can get another one if needed for silly amounts of power.
Seems to be nice at low impedance and high current situations.
Wow, it gets warm in CLASS A so keep the music going!
Good paper specs on S/N and separation.
I can actually pick this amp up at 85 pounds.
Price is “reasonable” for a high-end amp.

My second choice is a PASS LABS X350.5 as I’m told that the sweet spot for PASS A/B sound is this amplifier. PASS pure class A is too expensive.
40 watts of class A capability may capture the sound I need?
Seems to be a solid design and also with good sonic ratings.
WAY more power than I’ll ever use, though.
Never need to buy another amp for power.
Stable into low impedance.
I CAN NOT safely pick this amp up at 135 pounds!
Price is “reasonable” if you can find a used one for a high-end amp.

My third choice is an ANTHEM P2 that some say is a giant killer (I don’t see any dead giants laying around anywhere, though).
Seems to be a more standard A/B amp for home theater but…I keep being told to listen to it.
Seems to be a solid design (full of protection circuits).
WAY more power than I’ll ever use, though.
Never need to buy another amp for power.
Stable into low impedance to an extreme.
I can pick this amp up at 75 pounds.
Power rating and light weight make me wonder about the current delivery capability.
Price is “reasonable” for a high-end amp.

My fourth choice is a BOULDER 860.
Doesn’t seem to “double-up” on power into 4-ohms.
Can’t be run “mono” to add one later on.
Built well.
Paper specs are impressive (S/N and separation) but gets a knock for harshness in the midrange.
Seems awful light at 45 pounds to provide a big current reserve in the power supply.
Price seems high for the lightweight power supply.
rower30
p59teitel
312 posts
 
"After that we listened to the PLINIUS SA-103. Rats, this unit sounded too warm (sound, that is but it did get physically HOT) and also not rich and detailed enough."

Well there ya go - I did mention that it was a little rolled off, but I guess you found it a lot rolled off! No surprise really, given that you prefer the Boulder and Sim gear.

I'll second Xti16's recommendation to check out Burmester and Soulution, as they should both provide the level of detail you crave.
rower30 OP
211 posts
 
P59teitel, your dead right on that call (someone has to be right, eventually!), the softer nature of the SA-103 surprised me being CLASS A and all. It was a thirty-second read.

Well, I can't afford a Burmester! I'm deeply into the used market for a Boulder 1060 (12-14K range). I think I've lost my mind at 10-14K! But, I'll use it till they shove me in a square 8-foot deep hole. So the buck stop at or south of 14K.

The SIM unit I listened to was a 700i dual MONO, 175 watts/channel. It was VERY good sounding. It was detailed without being thin. Mids were full deep and against a pure black backdrop. Bass was exceptional with a HUGE soundstage. I need to get a W8 or the 860A and the PASS XP-10 going.

I'll have to get back on the Octave integrated I listened to. It was good, but after the i700, no way would I stay with it. I'm not being mean to you tube lovers, I heard the "magic" in the texture of voice on the Octave, for sure. It was nice but, my ear just goes to the detail like a moth to a flame. It's me. Nothing has it all, so you seem to settle on one side or the other.

I have to drag my XP-10 and KISMETS over to try to square-up what I can expect from my XP-10, and what level of improvement I hear from the KISMETS which aren't terrible at all. But against this level of stuff, I expect a difference akin to the Octave verse the sim i700. Both are good, one is better!

Remember, I'll go full balanced with the SIM 860A or Boulder 1060, too. The XP-10 is supposed to be much better with balanced out-puts.

Thanks for hanging in there on this thread. You all are in a better financial deal with the eventual outcome compared to me!
p59teitel
312 posts
 
Hey, I just thought of another brand for you to try: Spectral. Very detailed and known for precise soundstaging too.

"You all are in a better financial deal with the eventual outcome compared to me!"

As a lawyer, I am professionally trained to spend other people's money. :)
ejlif's avatar
ejlif
1,373 posts
 
Keep us posted on the results of the boulder 1060 if you get it. Sound like a solid choice to me
rower30 OP
211 posts
 
The 1060 was awesome...and over my limit...darn. It had the same sound at any volume. It never seemed to have dynamic compression.

But, I have a line on a MOON W-8 in good condition for 10K and tax (right at my limit). The XP-10 preamp ends up having laser sharp imaging and spectral location to harmonics off the fundamentals. Imagine a cymbal strike. The overtones are dead nuts emination from the location of the fundamental "snap". No other preamp did this, and it, to me, makes music sound live. At least that's what my brain "hears" as it turns out. I had no idea till we switched preamps all around. The XP-10 is an imaging and soundstage precision killer!

Ok, what's not to like about that? It can get harsh on bad stuff, making you back down the volume. What's this got to do with the MOON W-8?

The W-8's are known for a very big soundstage and a smooth solid state sound, that should soften the XP-10 deficiencioes some. To back that up, the i700 MOON was SMOOTH like the Boulder, but with a bigger soundstage at the expense of a little imaging that was so good on the Boulder amp / pre combo. I do mean a little. You kind of liked either amp.

So, the XP-10 with the MOON W-8 may be a nice fit with my C4's. The W-8 has the zero feedback LYNX circuit and a decent amount of power.

I will drag those HEAVY KISMET amps and XP-10 back to the dealer and listen to the XP-10 and the MOON W-8 when the new owner get his MOON 870A (lucky %&$%#@%).

Still, for 10K I think that the Candian built W-8 with five years warranty is a nice amplifier. I just hope it marries my pre-amp well. This take a LOT of time. If not, we soldier on to more of your suggestions. But, I have no "home base" for sonics after I leave Hanson Audio's set-up. Their room is just plain sickeningly good! It is not "live" or "dead" but images with surgical precision. That pisses me off when I go home! My room is next.

Hansen audio is about tired of me by now...as all of you are, too!
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