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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
rower30 OP
211 posts
 
..Sounds like you've answered your own question...

Well, I wish that was true but I'm not that smart. So far this has been mental gymnastics, really. If this was all audio was it would be too easy.

Yes, I have Dynaudio C4 Signature II's. And no, these are not fatiguing to listen to at all. I find them superbly rich and detailed. I do agree, however, that if you like that softer type sound these are probably NOT the best choice for that. I keep going back to the more detailed sound I seem to enjoy and the big Dyn's provide this with exceptional balance. These are one of the few speakers I've heard that make ensamble music on vocals sound "real". The midrange texture and richness is, to me, addicting.

Loud? I hit 80-83 dB average SPL and maye 90 dB peaks when I listen. Not sure if that's "loud". No, I would not say this is quiet. It's foreground volume, not background.

So I'm considering class A or high bias A/B amps, which on paper extract the absolute best in imaging precison. The C4's will let you hear it if it is there.

For standard A/B amps, the KISMETS are great. Doing better isn't an easy task. An at home better A better B comparison will let me know where this can go sound wise.

Any Plinius SA-103 users out there? Does this amp deliver the CLASS A goods like you expected?
arh
366 posts
 
I have been a tube guy all my life. Have briefly had a Krell Ksa 50 and Odyssey Khartego. My tube amps have been Audio Research, Conrad Johnson, Cary and VTL. Recently discovered an amp that is the best I have ever heard. It is the Gilmore Raptor 500D mono blocks. Believe it or not this is a class D amp which is just astounding. Deep powerful base with gorgeous top end. Resolution is better then any other amp I have heard.
Great micro and macro dynamics. 250w/8 ohms and 5003/4 ohms. They are $2500 for a pair of monoblocks and weigh 37 lbs each
Alan
zd542
5,339 posts
 
I've read through your post and you seem to be on the right path. I think you should keep #4 mandatory, if at all possible. Also, while you can look at the design of an amp and maybe point yourself in the right direction, in the end the amp has to stand on its own 2 feet with regards to sound quality. Some amps have 4 rubber feet. Thats OK too. Just as long as it sounds good.

I've had several Pass amps, the McCormack you mention and an old Boulder. Never had a Plinius. Also, I think its safe to say that a newer Boulder amp would sound much different than the old one that I had. Given all that, the first amp I would recommend you look at is Ayre. I feel their products are state of the art for SS. That doesn’t mean that you will like them, but to not consider them would be a mistake. Generally speaking a lot of people say that they are analytical. I don't believe that’s an accurate description. Ayre does pass a huge amount of detail through their products but its the cleanest, purist, most liquid solid state I've ever heard. In my main system, I have 2 V5's biamped vertically powering my speakers. Depending on how big your room is and how much volume you need, 1 V5 may be all you need. I won't lie, though, 2 is better.

"I can get BOULDER products but they are WAY high priced." By that statement, I take it you live somewhere near boulder. Ayre is made in Boulder as well, so there should be no problems there.

If it turns out that you don't like the Ayre for some reason, I highly recommend you listen to BAT. In my opinion, they are in the same league but they do sound a little different. Their SS sound falls somewhere in between Pass and Ayre.

One last thing. The weight issue. Are you kidding me? Its not like a girl that you have to go around and be seen with. You need to suck it up on that one. Pay some to move it or through your back out. This is your audio system were talking about here.
altanpsx
70 posts
 
If u find a chance, try asr ii.
peter_s
1,335 posts
 
Gamut is worth considering. As for weight, I have 200 lb Classe Omegas, and have learned how to move them around the room just fine. There are ways of doing this - just like the Egyptians built the pyramids. If you have to get them up/down some stairs, you'll need help.
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