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

Raquel,
Well stated words of wisdom, but only if genuine music quality is the objective as opposed to spectacular Hifi. I`ve come to belive that the advent of inefficient speakers has been counter productive for the persuit of natural sound. It forces one down the path of ever bigger and more complex amplifiers to drive them.

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

Raquel:

What do you mean by "you are going to suffer when you are not listening to extremely loud music" ? If i'm listening to normal levels i should be on class A up to 80 watts.
It is not the same thing as haveing XA160.5 ?

Check the specs of the Pass amps. I think the X350.5 has about the same current as the XA100.5. The XA100.5 also has more class A watts and doubles output as impedance is halved, so 200 watts at 4 ohms. I would stretch for the biggest XA.5 you can afford, BUT your Strads are pretty efficient, though I don't know the impedance, so the XA100.5 should be plenty. Of course, you should listen to be sure.

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.