Pass Labs Aleph Question

I have 2 Aleph 5's and they are one of the finest sounding amps I've ever heard. Drawback, only sound good when warmed up (at least an hour), will double your electric bill if you leave then on and aren't suitable for difficullt speaker loads. Match then up with some fairly efficent speakers. I have B&W Nautalus 802's and they work fine.

I have the Aleph 4's which are a stereo version of the Aleph 2's. I corroborate those who say that the Aleph
amps are some of the finest ever made. They are extremely neutral, deliver tremendous detail in the highs while always sounding natural and unforced. Even the most minory colorations which I find in my system are always proved to exist elsewhere, not in the Aleph 4's. I use them with the inefficient, 6 ohm Vandersteen 3A Signature in a romm which is 22'x12'x8' and which is open to adjoining spaces. There is no bass problem. Bass is extremely deep and will do any pipe organ recording justice. This amp can rattle floors and windows if you are into that. What it doesn't do is give you the ultimate bass slam. The bass is not super-tight and punchy, but who cares! It is a wonderful amp in every respect. I have heard the Pass X series (X350 and X250). In my opinion, they don't compare for naturalness and for absence of all electronic artifact. Sorry Pass Labs, but that is my opinion. The fact that they developed the super-expensive XA series, followed by the X+ series in order to bring the sound of the Aleph to the X series would suggest that someone was not completely satisfied. I say just save your money and buy an Aleph. From some of the posts here, you might want to stick with the more powerful Alephs. I have heard the Aleph 3, the Aleph 4 and the 1.2 (200W monoblock). The 3 did sound a little underpowered in certain situations, but it is also a wonderful amp.

I also have a friend who runs an Aleph 4 with Vandersteen 3's into a room which is 27' x 18'. The ceiling ranges from 8' to 9' directly above the speakers, but at the other end of the room, the ceiling is over 20' high at its peak (cathedral ceiling). This room is open to other rooms on either side. He likes his music extremely loud and the Aleph has no problem with this setup, i.e. it never sounds thin or under-powered or gives any discernible sign of strain. It is my perception that the Aleph 4, being the last Aleph produced, may have better bass than the Aleph 2, but since I have never heard the Aleph 2, I arrive at this mainly from matching my Aleph 4 experiences with the comments of others about the Aleph 2.

I heard the Dunlavy 4's with a pair of Pass Aleph mono's running either 90 or 100 watts per channel. Nice but nothing special. Later heard the very same speakers with 4 200 watt mono's of a much lesser pedigree and liked them way better. I think the Pass x1000 mono's are amongst the best amps I've ever heard.

I'm currently using Aleph 1.2 monoblocks on Apogee Studio Grand ribbon speakers (with Aragon Palladium II monos on the subwoofers). These run around 5-6 ohms. Prior to my acquisition of the Studio Grands I ran them with Apogee Duetta Signatures (3-4 ohms).

Both speakers have fairly constant mostly resistive impedance curves and the minimum impedances lie right in the optimal portion of the Aleph 1.2 power/impedance curve.

The Alephs are magic on both speakers. The Studios have much better dynamics than the Duettas and the Aleph/Studio combination provides slam as well as sweetness and delicacy.

The downside is that they are space heaters. Each amp pulls a constant 600 watts from the power lines and most comes back as heat. I need suntan oil and a beach chair for winter listening sessions when the A/C is off.