pass labs xa30.5 vs aleph 3

Tvad's points are well taken. FWIW, Pubul57 came to the same conclusion after comaring the XA30.5 and the Amta-Sphere M-60 on his Merlins. I have been very impressed with the XA30.5 on my Geddes Abbey speakers. It smoked my hybrid amp. My speakers are 95db efficient, 8 ohm nominal impedance and have a reasonably flat impedance curve. Ralph Karsten of A-S reviewed the impedance curve and said these speakers are very well suited for his amp and recommended either the S-30 or the M-60. I bought a M-60 and will post my impressions after I have a chance to make a comparison. Having either of these amplifiers in your system is a problem of riches IMO.

I think Madfloyd already summed up a lot of my thoughts on the sound differences between the XA30.5 and MA-1's, so there really isn't much more for me to add on that front. Simply put, the system lost a good deal of its "magic" when the MA-1's were taken out and replaced by the XA30.5. For the majority of my listening, I didn't see the meter move on the XA30.5, so I don't think it was running out of gas or being pushed out of Class A mode. As such, I don't think it was an "unfair" comparison with the MA-1's.

While Tvad is certainly entitled to his opinion (and I do respect his opinion) I am in full agreement with Madfloyd in
that we both heard so much of the Pass sound of his XA100.5's when the XA30.5 was put into my system. While Madfloyd would have no issue with bringing his amps over to my place, I did indeed tell him that I didn't think it was necessary. Maybe one day I will take him up on the offer, but for now my curiosity has been satisfied.

Getting back the to the Atma-Sphere amps...I don't think the improvement of the MA-1's over the M-60's is so much about the extra watts, as it is about the ability to work better with a 4 ohm load. With the M-60's, I felt that I had to use the Speltz Autoformers with the 5A's to sound their best, while the MA-1's didn't require them.

I plan on talking to Ralph next week about upgrading my MA-1's to Mk 3.1 status (from Mk 3) and will ask him his thoughts on this subject.

George

I had a chance to A/B the XA30.5 vs the Atma-Sphere (A-S) M-60Mk3.0 (with stock driver tubes - not the NOS which are recommended for top performance) on my Geddes Abbey speakers.

The Abbey's are a large sealed box 2 way monitor with a compression driver mated to a 12" waveguide and a 12" pro woofer and roll off at 50Hz 12db/octave. I use servo subs for the LF. They are 95db efficient, 8 ohm nominal and have a reasonably flat impedance curve which has a dip to 5.5ohms. According to Ralph Karsten and Duke who saw the impedance curve, they are well suited for the A-S.

My source is a Zalman silent music server with a Lynx AES/16 card driving a Berkeley Alpha DAC which has a built in pre-amp section with XLR and RCA outputs. I drove both the XA30.5 and M-60 with balanced outs.

The superiority of the A-S was evident within seconds. It was not a subtle difference. My wife, who is the ultimate anti-audiophile, for the first time ever asked me why the system sounded so much better and sat down to listen to some tunes.

I observed the same thing as Madfloyd. While I regard the XA30.5 as the best SS amp I've heard in recent memory, it doesn't come anywhere close to the A-S in terms of transparency, dynamics, tonal texture/shading, soundstage depth/width. I never thought a 2 channel system could get this close to sounding live. The realism of the musical presentation was magical.

In terms of power, I only have half the power tubes in my M-60's presently and they had no problem blowing me out of the room. Of course as Tvad has noted, this is very speaker dependent and YMMV. I'm going to get my M-60's upgraded to Mk3.1 level and buy some NOS driver tubes.

Glad things worked out for you Earflappin.

George