Guidocorona, I too was concerned regarding if the XA amps would have enough current/drive to adequately power my MG-20's, that's why I first went with the 350.5 with great results. Remember, I bi-amp so the 350.5 was only driving the midrange panels and ribbon tweeters, not the bass panels. However, regardless of the type of music or volume levels that I normal listen to, the 350.5 never really moved out of its 50 watts of class A and maybe crossed over into A/B for a very few watts on the largest transient peaks. So, this lead to many discussions regarding the nominal ohm rating of Maggies, which is six, that they are not necessarly a hard load, but love current and finally their not the most efficient speakers as you stated in your post. Well, and I'm thrilled about this, I hear absolutly no strain, compression or distortion on any type of music or volume levels in my system.
To address your three main questions regarding the sonic differences between the XA-100's and the X-350.5 which lead me to make the change:
1) The soundstage is not smaller or bigger with the XA-100's compared to the 350.5, but I believe more accurately gives you what the recording has to offer. Also, since the XA-100's have the greatest image density and air around individual players with a three dimensionality I have ever heard in my system, the amps give you a sense of "intimacy" that kinda brings you closer to the source without shrinking the soundstage. If your listening to a big band recorded in a large acoustic space you get it, if if its a quartet in a small club that's what you hear. Now, remember, up to hearing the XA-100's in my system the 350.5 produced the best soundstage I had ever heard, compared to my Edge NL-10 a fine amp that came no were close to the 350.5's soundstage both in height or width and layering in the acoustic space, but the XA-100's are qualitatively better in my opinion.
2) I do not like to write descriptions of the sonics of different gear in highly subjective or mumbo-jumbo ways, however, sometimes its hard to describe special qualities only in analytical/objective semantics. In this case, its regarding your question conerning the authority of the XA-100's. Well, how about this fractured analogy, the XA-100's are the proverbial " iron fist in a silk glove". They offer great dynamics with terrific weight to the different players, yet at the same time are easy, relaxed, and airy at the same time. Hope that makes some sense to you.
3) The reason I decided to make the switch from the 350.5 to the XA-100's, and feel very fortunate that I can, mainly comes from a very special aspect that you get with the XA-100's, which the 350.5 offered a small taste of, which is these sense of "easyness/effortlessness/liquidity" that just lets me in a more natural way get more into the music. I'm not talking about an euphonic coloration or a fat over ripe richness I have heard with certain tube amps, but a wonderful ease and natural presentation that makes it easer to relax and enjoy the music I'm listening to. That does not mean that these amps lack impact or prat, I was just listening to Charlie Hunter's, Steady Groovin', and the music was rocking my room, but that special quality of drawing you in to the music was still making it easer to get into, in this case, the groove.
I enjoyed totally my time with the 350.5 powering my system for over a year and a half. I still think it's one of the best SS amps out on the market and will compete with virtually anything in a highly competitive way. The XA- amps will not power as well some very difficult speaker loads, were the 350.5 well sound and work better, but if XA-amps can control the speaker, I believe they offer something very few amps have in their sonic signture. Remember, at this level of gear , their are many great sounding pieces, so personnal taste and synergy are really the final determinant. For me the XA-100's are the best I have heard in my system. Please, Guidocorona, if I'm still not answering your questions specifically enough let me know and I'll try my best to address them in a more helpful way.
To address your three main questions regarding the sonic differences between the XA-100's and the X-350.5 which lead me to make the change:
1) The soundstage is not smaller or bigger with the XA-100's compared to the 350.5, but I believe more accurately gives you what the recording has to offer. Also, since the XA-100's have the greatest image density and air around individual players with a three dimensionality I have ever heard in my system, the amps give you a sense of "intimacy" that kinda brings you closer to the source without shrinking the soundstage. If your listening to a big band recorded in a large acoustic space you get it, if if its a quartet in a small club that's what you hear. Now, remember, up to hearing the XA-100's in my system the 350.5 produced the best soundstage I had ever heard, compared to my Edge NL-10 a fine amp that came no were close to the 350.5's soundstage both in height or width and layering in the acoustic space, but the XA-100's are qualitatively better in my opinion.
2) I do not like to write descriptions of the sonics of different gear in highly subjective or mumbo-jumbo ways, however, sometimes its hard to describe special qualities only in analytical/objective semantics. In this case, its regarding your question conerning the authority of the XA-100's. Well, how about this fractured analogy, the XA-100's are the proverbial " iron fist in a silk glove". They offer great dynamics with terrific weight to the different players, yet at the same time are easy, relaxed, and airy at the same time. Hope that makes some sense to you.
3) The reason I decided to make the switch from the 350.5 to the XA-100's, and feel very fortunate that I can, mainly comes from a very special aspect that you get with the XA-100's, which the 350.5 offered a small taste of, which is these sense of "easyness/effortlessness/liquidity" that just lets me in a more natural way get more into the music. I'm not talking about an euphonic coloration or a fat over ripe richness I have heard with certain tube amps, but a wonderful ease and natural presentation that makes it easer to relax and enjoy the music I'm listening to. That does not mean that these amps lack impact or prat, I was just listening to Charlie Hunter's, Steady Groovin', and the music was rocking my room, but that special quality of drawing you in to the music was still making it easer to get into, in this case, the groove.
I enjoyed totally my time with the 350.5 powering my system for over a year and a half. I still think it's one of the best SS amps out on the market and will compete with virtually anything in a highly competitive way. The XA- amps will not power as well some very difficult speaker loads, were the 350.5 well sound and work better, but if XA-amps can control the speaker, I believe they offer something very few amps have in their sonic signture. Remember, at this level of gear , their are many great sounding pieces, so personnal taste and synergy are really the final determinant. For me the XA-100's are the best I have heard in my system. Please, Guidocorona, if I'm still not answering your questions specifically enough let me know and I'll try my best to address them in a more helpful way.