Digital Amps vs Solid State Amps

Hi Vince,

I don't know what is installed. I am currently using the pair Henry had been using in his system for the last year. He said they are the latest of whatever he stuffs into them. They sound very good.

Alan

Hi,

I've owned the Pass XA 100.5 mono amps for a little over a year, but recently sold them. I've also owned H2O Audio class D amps for a long time, and am currently using H2O mono amps to drive my Avalon speakers. So, I have compared both these amps directly with my speakers and have also listened to both amps extensively with the Magico V2 speakers. The verdict? They are both great when set up within the right system.

I think both the Pass and the H2O amps sound wonderful but in different ways, and my preference comes down to system matching. The Pass XA.5 amps have a full, warm sound with a glorious midrange and very smooth high frequencies, and sounded beautiful with the Avalons. However, the Pass amps don't have the control in the low end that class D amps generally exhibit.

The H2O mono amps don't flesh out the midrange as much as the Pass amps do, but they are still wonderfully liquid sounding through the midrange. They can be amazingly good sounding in the right system. I preferred them to the Pass when mated with the Magico V2.

Alan

Hi Dob,

I respectfully disagree that the XA200.5 would control the bass of my speakers better than either the Spectron or the H2O.

I don't think the wattage of the amplifier is what determines its ability to control the low end of the speakers, as much as it is the overall topology of the design. While the higher line of the XA.5 series has more wattage and current available, you will notice that the damping ratio of the XA200.5 is exactly the same as the XA100.5, and I imagine that's due to the overall topology of the amplifier (its low loop feedback).

I've listened to other 100 watt amplifiers in my system, similar in power and current specifications to the Pass XA.5 series, that have controlled the bass far better than the Pass mono-blocks. So I think that if you use an amp designed with low or no negative feedback mated to a speaker with a difficult low frequency impedance load, the result will be comparatively loose bass control, no matter how much wattage the amp pushes out. If my speakers had a more friendly impedance load, I think the Pass would control the woofers to my satisfaction.

In contrast, an amp like such as Spectron or H2O has a much higher amount of loop feedback and a higher damping ratio, and that's probably what allows it to control the woofers of a low impedance bass load.

Alan

Hi Rtn1,

I am sure that I would love the XA160.5 or XA200.5, as I thought the XA100.5 produced a beautiful sound in my system. The midrange and top end of the Pass is wonderful. I like the richness of the bass too, but with the Opus it is a bloomy bass more suited to classical music; it didn't have the micro-dynamics and pitch definition that made for great acoustic jazz bass when mated with the Opus. In my system, I never saw the Pass bias needles moving so I figured power was not the issue.

A friend of mine still owns the XA100.5 and another friend owns the XA160.5. Maybe if I hosted a nice dinner and promised to pay for their hernia surgeries, I might convince them to lug the amps over for a side by side comparison.

Alan