pass labs xa30.5 vs aleph 3

George, as you are one of the few people I've come across that has heard both of these excellent amplifiers in the same system with speakers which were compatible with the Atma-Sphere, could you provide a more detailed summary of your impressions? I take it your friend's XA30.5 was fully burned in and you listened to it fully warmed up? Thanks.

George, as you are one of the few people I've come across that has heard both of these excellent amplifiers in the same system with speakers which were compatible with the Atma-Sphere, could you provide a more detailed summary of your impressions? I take it your friend's XA30.5 was fully burned in and you listened to it fully warmed up? Thanks.

George, my thanks to you for sharing your experience with the A-S amps, as well as to Pubul57. I had to buy the M-60 without having heard it and the conversations with you guys gave me the confidence to take that risk.

I would agree with Pubul57's conjecture about the Aleph J vs the XA30.5. Also, First Watt has come out with a new J2 amp that should sound really good as well, but the output power is fairly low.

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 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.

Jbarnett, thanks for your post. What speakers and pre-amp are you using? I was going to try the J2 but at 25W into 8ohms Nelson and Mark at Reno Hi-Fi thought it wouldn't have enough power to drive my 95db efficient speakers.

Have you auditioned the Atma-Sphere amps? I would describe them as having both of the attributes you mentioned - a startling aliveness with a soothing sweetness, especially the midrange.

I hear ya Tvad..... I thought the same thing...i.e. 25W should be enough power. Once there are some more reviews out there on the J2 I may have to try one just for the sake of curiosity.

Thanks Jbarnett. I have spoken with Clayton on several occasions and have deep respect for his speaker designs. I especially liked the evolution from the 2.0 to the 2.3. I almost bought the 2.3's in fact, but my current listening room forces the speakers to be within a foot of the front wall and even with room correction it seemed a bit of a stretch for the 2.3's. So, I went with the Dr. Geddes' Abbey speakers which also use a compression driver tweeter with a 12" waveguide and a 12" pro woofer, but in a sealed box so placement near the front wall is not an issue. The sound is to die for. I suspect it is similar to the 2.3's. Are you using the stock Behringer cross over?

I have a Zalman fanless PC running Windows 7 64 bit with an AES16PCI card going AES/EBU into a Berkeley Alpha DAC which also serves as my pre-amp. I use XXHighEnd as a software player which to my ears is better than iTunes. XXHighEnd is designed to turn off unnecessary software services and use a dedicated CPU core for playback. I am getting sound quality like you that I am simply amazed with even on CDRB.

I hear ya about the tubes....I had managed to avoid tube amps my entire audiophile career having owned Spectral, Halcro, Boulder, Linn SS amps. Now that I have my A-S OTL amp I must say that tubes are really not that much of a hassle. In fact, I kind of like the retro look of the A-S amps.

Oh well....that's what I love about this hobby....there are many ways to musical nirvana.

Pubul57, yes, I just had my M-60's upgraded from 3.0 to 3.1. My understanding is that the upgrade involves an evolution of the voltage amplification circuit which reduces distortion by 95% at full power. The improvement was not subtle to my ears. More transparency, detail and fluidity in the presentation. Easily the best bang for buck upgrade I've ever made to my system. I highly recommend it.