Pass XA.60.5 Monoblocks to Pass XA.100.5 Monoblock

I had written a review of the Pass XA.60.5 Monoblocks so rather than do another complete review, I thought it might be more informative to discuss the differences I have experienced when I recently upgraded to the Pass XA100.5 Monoblocks. I had asked for feedback on Audiogon about making such a change and would like to address some of the responses I received (and appreciated) now that I have had the real world experience of listening to the new amplifiers. I always have mixed thoughts about component burn in but for the sake of clarity, I have over 300 hours on the new XA 100.5 monoblocks. All of the other components and cables have remained the same from the time of the previous Pass XA60.5 monoblocks. The room is the same, my living room, which is 12 by 23 with the loudspeakers on the short side about seven feet apart, fifty six inches from the wall behind them, and about 2-3 feet from side wall and staircase on the other side. Certainly, not a perfect room, but we do the best we can with what we have. I will say that I have had systems in much larger rooms years ago and personally have been able to achieve better sound in a smaller room given imperfections in all the rooms I have had my systems in.

I should again mention the loudspeakers as they are a very important factor in the determination of the match with amplifiers. I have Tyler Acoustics/Woodmeres which have a sensitivity of around 89-90. These are fairly large speakers that are 4 ohm and have two 10 inch bass drivers, 2 seven inch mids, and the tweeter and are all SEAS drivers. If you look at the system photos, you can see the speakers. They can take a good amount of juice and the drivers react to any kind of component change I have made over the period of time I have owned them.

Some of the issues I will discuss are the following:
*2db change from Pass XA60.5 to Pass XA100.5
*Stereo XA30.5 to XA60.5 to XA100.5-"sweetness of the sound"-concept that you lose some when you increase the power of the amp
*Soundstage and Imaging Details
*Bass (quality and quantity)
*Weight and Fullness of Sound
*Knowing what I do now, would I make the change again with the current information and knowledge?

2db change from Pass XA60.5 to Pass XA100.5

One of the thoughts that was expressed to me about the upgrade was that a 2.25 db change would mean nothing and the sound would not be very different. Well, the change in power makes a difference and in my case with my speakers in my room, makes a big difference. With the XA100.5, the system has the capacity to play very loud and at a very high quality but the bigger change is at lower listening levels, and normal listening levels. My music, whether rock, classical or jazz sounds more lifelike through the complete sound spectrum, highs to the lowest bass. The XA100.5 have the capacity to drive a more demanding speaker. Mine are somewhere around 89-90 4ohm( not inefficient) and the ease of the XA100.5 to drive them is highly evident. The XA60.5 did not take control of the speakers in the same way and the XA30.5 was not able to match well with the speakers due to the lack of power. Could one live with the XA60.5 and my speakers, in a word yes. It would be someone who does not push the amps by playing them loud at times or have the kind of music that tends to have dynamic swings. In my experience with the XA60.5, I pushed them enough that they went into A/B a fair amount of the time. Truthfully, I think the XA60.5 Monoblocks would be better with other speakers that are easier to drive.

Stereo XA30.5 to XA60.5 to XA100.5-sweetness of the sound-concept that you lose some when you increase the power of the amp

I read threads where audiophiles comment that the XA30.5 is the sweetest amp in the XA line and when you go to the higher powered amps, you lose that sweetness. Well, that is just not true in my experience as someone who has owned half of the XA line. The XA60.5 and now the XA100.5 have every bit of sweetness that the stereo amp had. I don't feel I lost anything in this area with the higher powered amps. I wonder if those who believe this have really heard many of the amps in the XA line. I have not heard the XA160.5 and the XA200.5 but if you have concerns about upgrading from the XA30.5, in terms of losing the sweetness of the sound, the mono blocks will give you all that you get from the XA30.5 and more. That is my opinion from owning these amps. My bias over the years has been to monoblocks. I think they drive the speakers with more ease than a stereo amp but that is always open to debate.

Soundstage & Imaging Details

The soundstage is wider than with the previous amps. I hear more sound coming from the sides behind the speakers. The images are more focused as if a lens has sharpened the picture. I hear and feel the separation on stage with all of the instruments and sometimes with the XA100.5, I am actually fooled as I hear things that I have not heard on a particular CD and it takes me a couple of seconds to realize that the particular CD was generating that sound. I actually have thought that something else was going on in my room. In addition, I hear more of the subtle information with the XA100.5 vs the XA60.5. I mean hearing the breathing of the performers and background instruments that I have not heard previously. The bigger amps pick up those nuances in the music much more than the other XA amps I owned. The images are bigger and fuller and that improves the presentation of the music.

Bass

The Tyler Woodmeres have the capacity to go pretty low and with the XA100.5 amps, there is an increase in the amount of low end that I hear. I can better differentiate the lower note details . The bass is more realistic using the XA100.5 than with the other XA amps I owned. Of course, if you have a loudspeaker that does not produce and deliver much of the low end, no amp is going to make that appear. The loudspeaker will need to have the ability to go low. Many speakers I have owned, quality loudspeakers, did not go very low, and the amp change would not have affected those speakers.

Weight and Fullness of Sound

Now we are getting to the core of the change and the biggest difference I experienced so far by upgrading from the XA60.5 to the XA100.5 monoblocks. My system is getting a much bigger sound in terms of fullness and weight. The smashing of the drum kit seems more realistic to me. On many of the recordings where there is much percussion, I can better imagine the drummer really hitting a full drum kit. All of the instruments have a larger, more realistic sound, including voices. The whole sound has a more weighty feel to it and that gives it a more realistic feel than what I previously had. Its hard to convey these changes without someone hearing the two sets of mono blocks but the XA100.5 give a bigger sound to the system and a thicker deeper sound to the system. These amps are taking more control of the drivers and the sound reflects that.

Knowing what I do now, would I make the change again with the current information and knowledge?

Well, as one goes up the XA line, one pays the price for the more powerful amps so there is always the question of whether the upgrades are worth that extra money spent. It hard to put an exact per cent in terms of improvement. All I can say with system component changes is that I have tend to have one of two reactions. One is that the effect is minor and not worth additional money and the other is that the change is great enough that I want to keep the new component and it is a significant improvement to my system. This change from the Pass XA60.5 mono blocks to the Pass XA100.5 Monoblocks is one of those significant changes. I am getting so much more from these amps and the system is playing at a higher level which is really all I can ask from a component upgrade. Again, it is always system dependent. I think that if my speakers were not as power hungry, the change would not have impacted to the same level. I have found that my Tyler Woodmeres are very sensitive to component changes which helps in evaluating what is happening. I have noticed this with amps as well with sources. I was surprised how much the system was effected by changes in the CD source when I tried about five different players in the system some months ago. And last but not least, the room is many times the biggest component in the whole system. It effects every aspect of how the system sounds including the amplification. I certainly do not claim to be any type of expert in the audio world. I have learned whatever little I know by trial and error. As you can see from my posted system (Forever Done, Never Done), I have gone through a great number of components. My opinions are only offered so they can be of some kind of assistance to someone else who may have some similar amp choices to make. To be honest, I am hooked on the XA line of Pass Amplifiers. I have owned many amps and they have all had many fine qualities but the Pass XA line is something very special to me. Yes, they do use a fair amount of electricity but once burned in, I leave them in the standby mode. They have an alluring midrange, a wonderful transparency, image really well, give me very good low end, and play with an ease and smoothness that allows me to listen for hours. The Pass XA line is very unfatiguing and that makes a big difference to me. My music listening is my therapy. I work in a conflict management role and when I come home from work, i can be listening for 3-4 hours a night and much more on the weekends. My living room is my stereo room. (one advantage of living with just my dog, she is very tolerant) For a frame of reference, other amplifiers that I have had in my systems over the years included Simaudio Monoblocks (500 watts per channel), Musical Fidelity Nu-Vista Integrated, Musical Fidelity Tri-Vista Integrated, DK Design Integrated, Pathos Acoustics Logos Integrated, Bel Canto 500 Monoblocks and Bel Canto Stereo 500, Conrad Johnson Stereo Amp, Adcom 555, B&K Inegrated, NAD Integrated, and probably many others I can't remember at this point.

One last point on this thread. If you have a different point of view related to anything I wrote or anything responders to my thread write, that is terrific. All I would ask is that we are respectful of each other. I get tired of reading threads where people are not respectful of each other. You may have more knowledge about Audio than myself or someone else, but the connection to educate someone or just reach someone through communication cannot be effective unless we are tolerant and accepting of one another. I hope new people want to get into high end audio and I hope some of those people want to have a 2-channel system. We need to cultivate that interest in the high end. Snobbery, intolerance, being condescending and sarcastic, does not foster positive relationships. I hope others will get into High End Audio and that is up to us to encourage. Thanks for taking the time to read this whole thread and I look forward to any responses from potential Pass XA amp owners, current Pass XA owners, or anyone who else who wants to share their thoughts.