Sonus Faber Stradivari amp: X600.5 or X1000.5 ?


Hello,

I want to know which power amp is better for my new speakers (Sonus Faber Stradivari) combined with ARC REF3. Ive just listened a few days ago the X350.5 and i loved it so much. Right now i have a pair of MC-501 but i'm a little dissapointed of them when i try to listen to some complex music like rock and others. Is X1000.5 a good choice for it or X600.5? The X1000.5 have 2000 wats in 4ohms?
Anyone listened to both of them. Let me know.

Thanks.
johnb30

Showing 5 responses by raquel

The Strads are very sensitive, 92 db.+ and there is therefore no reason to use a high-powered amp with them, unless you listen at extremely loud sound pressure levels, in which event it makes no sense to use Strads (while they go plenty loud, they are primarily a finesse speaker).

It never ceases to amaze me how many people do not know that the vast majority of HIGH-POWERED AMPS SOUND MEDIOCRE. Big amps almost always use global feedback in order to control the circuit, which takes the life and dimensionality out of the music, and they also use dozens of output devices (i.e., lots of transistors or tubes) to achieve high power, which kills transparency and finesse.

More and more solid-state amp makers, from darTZeel, Ayre, the new Rowland, to Sim, as well as Pass (and many, many tube amp makers), no longer use global feedback in their curcuits. If you have really inefficient speakers or listen in a huge room, and you listen loud, then use a big Krell, etc. (even better, sell your inefficient speakers), but if you want your system to make recordings sound much more like real instruments, stay away from big amps and amps that use global feedback. You'll notice that the previous poster is recommending the 160 watt, Class A-biased Pass - not the 350, the 600 or the 1000.
Charles1Dad:

I see that you are running Coincidents - I recently put Total Victory IV's into my system and am very happy with them.

Johnb30:

The Pass amps are very good, but for a lot less money, the Parasound JC-1 monos are a very good sounding high-powered amp. They are also fully differential balanced and should work well with the ARC Ref 3 preamp.

Again, if you want an extremely powerful amp just so you can occasionally listen to rock and roll, you are going to suffer when you are not listening to extremely loud music. And the Strads can go loud and can handle some power, but they are not big Wilsons and should not be driven extremely hard. If you really
Johnb30:

Even at normal listening levels, peak signals can pull far in excess of 80 watts, which gives you the crossover distortion problems of AB operation. Full Class A operation has a lot of practical disadvantages (very high electricity consumption, a lot of heat, need to periodically re-bias output transistors), but manufacturers still make Class A amps, despite the practical disadvantages, because sonically, full Class A operation, when properly implemented and all other things being equal, sounds better.

In addition, all of the Pass amps, including the 160, have dozens of output transistors - on a transparent, finesse speaker like the Strads, especially given its very high sensitivity, you're generally going to get better sound using a high quality amp of 100-150 watts/channel that has a very small number of output transistors. The darTZeel, for example, is a zero feedback design that puts out approximately 150 watts/channel with only one pair of transistors per channel. The Pass is a very fine amp that has few gain stages and little or no global feedback, but you're going to hear the effects of all of those transistors in a high-resolution system.
Johnb30:

That's not the way it works. Again, every time there is a fortissimo passage, the speakers can draw far in excess of 80 or 160 watts, and the amp operates in Class AB. For pop or orchestral played at "normal" volumes, this happens all the time, which means that crossover distortion is always an issue. If you are listening to chamber music at 75 decibels at the listening chair, this won't happen, but it happens all the time with pop / rock / orchestral / big band jazz, etc. Again, if it wasn't an issue, amp manufacturers would not bother to make full Class A-biased amps, which are not easy to own (enormous heat and tons of electricity - mine draws 1,400 watts at all times and gets HOT).

I suggest that you make a judgment call as to just how much loud music you listen to. John Atkinson estimated the Strad's sensitivity at 93 db., which means that it is highly efficient - you do not need a high wattage amp to make such speakers go loud, just a well-built amp (i.e., stiff power supplies) that can deliver current (it drops to 3.3 Ohms in the bass). If you intend to listen to a lot of loud music, however, why not buy a loud music speaker, for example, big Wilsons? In any event, unless you do most of your listening at really loud volume, a high-quality 150 watt/channel amp, especially one that does not use global feedback, should make you happier in the long run.
It sounds like you intend to listen at very high volumes. The Strads can go loud, but you're talking about volumes well in excess of 110 db. You should talk to Sumiko (assuming that you live in the U.S.) or Sonus Faber to determine whether the drivers and crossover will hold up if played frequently at those kind of volumes. I ran Ebens which use Audio Technology midrange drivers like the Strads and they do not handle power as well as a lot of other drivers (in fact, other speakers that use Audio Technology drivers, e.g., Verity, Peak Consult, Rockport, are not known to be rock and roll speakers). For those kinds of volumes, I again ask why you are not using something like big Wilsons or horns.