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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
zd542
5,339 posts
 
I didn't know that your speakers don't allow for biamping. The reason I mentioned vertical biamping is that it eliminates all kinds of problems that you run into when you biamp traditional (horizontal). This is how it works. You need 2 stereo amps that are the same. Each amp powers one of the speakers. You run a cable from the right output on your preamp to both inputs on one of the stereo amps. (If your preamp has 2 sets of outputs, you can run 2 IC's. If you have only 1 output, You'll have to split it.). You then run speaker cables from the stereo amp to your speaker. One for the high's and the other for the low's. Do the same thing to the left channel.

The advantage of doing it this way is that you are working each amp the same because it is powering a whole speaker, as opposed to using 1 amp for the highs on both speakers and the other for the lows on both speakers. There's no need for active xovers or anything like that. You just hook it up and it works. Keep in mind, though, it only works with stereo amps.
xti16
1,525 posts
 
I have to mention the Burmester 911 or 956. My Dyn dealer had Sim and Burmester and I like the Burmester much better. I listened to those with the original C4's not the MKII/Signatures. I now have the C1 Sig's and they don't seem to need as much power as the originals.
rower30 OP
211 posts
 
OK, but there STILL has to be a passive X-over inside the speaker after you remove jumpers to allow vertical bi-amping as you can't, or don't want to, run full range into the mid/tweeter (assuming a three way speaker) and woofer. The set-up makes sens when you remove passive cross-over components.

C4's are not bi-amp capable. They are pretty efficient at 89 SPL rating and that seems to be accurate as they pump out WAY more sound than my Quatro's with the same amps.

Xti16, what stood out about the Burmester, and which exact model?

I listen to mostly chamber music and folk type music (smaller simpler ensembles) over Symphony and rock (larger busier ensembles). The C4 Signature II mids are to die for on this type of music.

xti16
1,525 posts
 
Honestly I can't remember if it was the 956 or 911 and neither can my dealer (NextLevelav). Anyhow for my taste the Sim had great 'control' with all the instruments and vocals BUT was way too detailed. After about a hour of listening I found myself not listening to the music but rather analyizing individual instruments and vocals. I found the same with Classe Omega but that was when I thought I liked B&W speakers. Now the Burmester had all the control with very good detail but was more musical. To me I would have to say the Burmester has better Prat. I found myself listening to the music again which for me gets my toes a tappin again. Unfortunately the Burmester is way out of my price range and have settled on an Octave V70SE tube integrated for my C1 sigs. Very good control and extremely musical. That being said with a few tube changes I can get more detail but seem to lose a little of that great musical sound. In other words I can change the sound characteristics by rolling some tubes and not having to replace the amp. BTW Dynaudio is the North American distributor for Octave and T+A.

Again these are my personal opinions based on my taste.
rower30 OP
211 posts
 
Yes, audio is odd in that some like less music to be "more" musical. I've switched around preamps and the tube units I've tried left me wanting...for detail and microdynamics. I just can't forget all the nuances of the music I hear with SS units that simple vanished with tube pre amps. Yep, the tube "harmonics" and tonal balance is there, but you loose the qickness and finer detail. My ear seems to want to hear all this. When I have a tube unit in my system, and switch it out, I don't want to go BACK to the the tube unit.
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Detail is not "hard" or glassy either. You can have a rich solid soundstage with good musical separtion and layering of the sounds with SS units. Tubes have been too "pastel" and seem to wash away information by design, much like a impressionistic painting. True, this is NOT the case with ALL tube units, but the ones that have been in my price range. A tube unit that can provide the harmionic structure and quickness with full rich texture with proper separation would be a gem, till the tubes change anyway.
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