An Amplifier Change for my Wilson Sophia 2's?

So if an amp i choose has more gain, that could be a benefit for the volume issues I have spoken about before.

It would lower the setting of the volume control that you would use to achieve a given volume level, everything else being equal.

And if the amp also has more wattage, it can control the speaker better ...?

Not necessarily.  That depends on several different characteristics of both the amp and the speaker, including amplifier damping factor and output impedance, how much damping is optimal for the particular speaker, how the speaker's impedance varies over the frequency range, the robustness of the amp's power supply, etc.  The bottom line is that it's hard to predict.

And if the amp also has more wattage, it can ... perhaps provide a better sound with high dynamic range music?

Stereophile measured the sensitivity of the Sophia 2 as being 88.3 db/2.83 volts/1 meter.  For its 4 ohm nominal impedance that corresponds to 85.3 db/1 watt/1 meter.  Neglecting room effects an amplifier capable of providing 100 watts into 4 ohms should be capable of driving a pair of speakers having that efficiency to a maximum SPL of about 99 db at a typical listening distance of around 10 feet.  That will be adequate for the great majority of recordings for the great majority of listeners. 

I for one happen to be among those for whom that kind of maximum volume capability would be inadequate, though.  I have a lot of classical symphonic recordings on audiophile-oriented labels such as Telarc, Reference Recordings, Sheffield Labs, etc., that have been subjected to minimal or no compression, and can reach 100 to 105 db at my listening position, on brief dynamic peaks, while being listened to at average levels of perhaps 75 db.

Would the increase of wattage of the amplifier allow me to hear the music better at lower volumes as well?

Again, it's hard to predict, and from a subjective standpoint it may depend on how the distortion characteristics of the particular amplifier vary as a function of the amount of power it is putting out.

All I can add at this point is that if you already haven't it may be worthwhile to research the Audiogon Virtual Systems to see what amps others have used with the Sophias.

One final point:  As with many ARC line stages and preamps, ARC recommends 20K as the **minimum** load impedance that should be presented to the LS25.  Keep that in mind in considering other amplifiers.

Best regards,
-- Al
 

Once Bob Carver created best amp: Sunfire Sig 600. It’s load invariant and can be used as welding machine as well(hey if needed).

It drives ANY speaker of ANY size super clean.

How about 1.2kW into 4 Ohms would sound like? I heard these speakers with Electrocompaniet AW 250/TaCT RCS2 preamp and the sound was ’hiding’ inside the box with no imaging whatsoever.

After they’ve been connected to this relatively light powerhouse mentioned above (hey, substantially lighter than Electrocompaniet), They started to open and showing soundstaging capabilities.

Using VT100 on Wilson Sophia speaker is similar to using Honda 1.5L engine on FreightLiner trucks. This is having in mind that you have ARC line stage with pretty high gain on the first place. 

Czarivey, 

wow, I guess you are saying My Sophia's are underpowered!  Obviously there are loads of opinions on this, but I am gravitating towards this opinion as well.  I called Wilson yesterday and spoke to one of the tech guys there.  He told me that Wilsons in general react very well to high powered amplifiers.

i think it's time for me to learn more about amplifiers. For starters I need to better understand the relationship between gain and wattage.

thanks for the input.

Hi Mark,

Regarding the relationship between gain and wattage, as I mentioned there tends in general to be a loose correlation, but one that is so loose that it is typically of no usefulness.

As you’ve probably found, the gain of both integrated amplifiers and power amplifiers is very often not specified. If Stereophile has reviewed the product the measurements section of the review will usually indicate the measured gain. In other cases the gain can be calculated to a reasonable approximation from the specified maximum output power and the specified sensitivity (the input voltage that is required to drive the amp to the specified maximum output power), as follows:

Gain is the ratio of output voltage to input voltage, expressed in db.

The ratio of two voltages, V1 and V2, are converted to db based on the formula (20 x logarithm(V1/V2)).

The rated maximum output power into 8 ohms (or 4 ohms) can be converted into voltage based on the equation P = (Vsquared)/R, where P is power in watts, V is volts, and R is resistance in ohms.

So for example in the case of an amplifier rated at 200 watts into 8 ohms and having 2 volt sensitivity, if we represent the output voltage corresponding to the 200 watts into 8 ohms as "Vout" and the 2 volt sensitivity as "Vin," we have:

200 = ((Vout)squared)/8

From which it can be calculated that Vout = 40 volts

Therefore the gain in db is

20 x log(Vout/Vin) = 20 x log(40/2) = 26 db

That is an approximation, as I indicated, in part because it does not reflect margin that may be built into the maximum power specification. But it will generally be a reasonably good approximation for most purposes.

Also, note that for a tube amp having 4 and 8 ohm output taps the gain will be approximately 3 db less for the 4 ohm tap than for the 8 ohm tap.

If you have a scientific calculator these calculations are very easy to do. Alternatively, the calculator that is built into Windows can be set to scientific mode, although I find using it to be somewhat clumsy.

Best regards,
-- Al

Well, Al,
If you and few other poster were speaking about where 100W per channel can bring Wilson Sophia, it’s not truly the case and I’ll explain why.
That ARC VT100 would be able to supply to my guesstimate only a third or a quarter of specified power which is only 25...30W realistically at highest volume setting. Although tube amps soft-clip, there’s still not enough CURRENT to move drivers and therefore actual power halves or even quarters. ARC line preamps in general have 20dB of gain so combined 80dB of gain is substantially enough -- no need to move gain higher to 73dB.
Mentioned earlier Bryston 3B-st or 3b-sst/sst2 amps can do much better job but still not enough.
As I’ve mentioned before 250W Electrocompaniet amp wasn’t enough either. It was loud enough, but no 3d and imaging.
400+Wpc/8Ohm and 600+WPC/4Ohm is about right ’prescription’ otherwise money wasted.
There’s one Sunfire Sig 600 for sale here on audiogon and I wish to stretch my budget and get it. I was foolish not to get it at more than half of price years ago, but trust me It’s the best amp ever made for any budget.

Increasing from 100 watts to 400 watts would give another 6 db of volume. Doubling the watts equals a 3 db volume increase. A volume increase of 10 db would sound twice as loud twice as loud.

In other words the starting point isn't 100 watts. Try going from 30watts: 60, 120, 240, 480 ... 12dB -- Now these figures bring you much closer to reality.