Passlabs Aleph 1.2 with CJ Tube 17LS/16LS Preamp

Aleph amps (I have an Aleph 4) have all the bass extension you could want. The bass is very deep and would easily surpass the extension provided by the McCormack DNA-1. What the Alephs do not have is the powerful,extremely dynamic, explosive mid-bass that passes for extension, but is not. With the right speaker, these amps will easily rattle the walls, floor and windows with deep bass. While the Alephs may be somewhat of an impedance mismatch with their 10,000 ohm input impedance, they work well with many other tube amps, such as CAT and even Audible Illusions Modulus 3. I have auditioned the Aleph P with the Aleph amps and felt that their were better choices than that preamp for my Aleph 4. I auditioned the Aleph 1.2's before buying the Aleph 4. Even though I have no complaints about the Aleph 4 in the bass, I recollect that the Aleph 1.2, which was twice the power, moved significantly more air in the bass. Since the Alephs are quite neutral and refined, even they give you quite a bit of subtle detail and soundstage etc., they may not have the greatest synergy with warm-sounding equipment like Conrad Johnson preamps. You might look at preamps which call a little bit of attention to themselves, like the Hovland. It is still quite neutral, and quite liquid through the midrange, but the highs are quite detailed and spotlit. However, be sure to check out the bass of the Hovland. I found it to be significantly rolled off.

I find the B&W sound to have plenty of mid-bass, not much bass below that mid-bass peak and a balance which favors the upper mids and highs. Generally, I have found this balance to be fatiguing in the long run as the emphasis of the upper mids and highs is quite evident and not natural. However, there are many who favor this sound. The Aleph 1.2 might have synergy with this speaker, since its character is the antithesis of this kind of sound. Any problem that I have had with the Aleph has had to do with it being so smooth that the upper mids and highs are sometimes too soft. This will not be a problem with the B&W, so these might complement each other quite well.

I have a pair of Aleph 2's that I use with Talon Audio Khorus's . At first I was using an audible illusions mod 3 a with this setup. I had loved the sound of the mod 3 with my previous amp (McCormack DNA .5)nad it sounded pretty good with this setup too. However when I switched to the Pass aleph P there was a night and day difference. The bass was more extended and tigher the midrange clearer and the highs smother. These observations have led me to conclude that perhaps triode tube preamps are not the best match for the alephs. I feel the Alephs work best with the Aleph preamp. For a tube preamp they might not be the best choice.

I agree that the 200w aleph 1.2's probably have considerably better bass. I have only used the 100w aleph 2's. They have the same power rating as the 100w stereo aleph 4. My point, and I do have one, is that compared to other 100w amps, the aleph's seemed weak in the bass. Somewhat related, I found the 185w mccormack dna1/reva was much much stronger. This was into a 4 ohm load audio physic virgo and 4 ohm magnepan 1.6. At his impedence, the aleph 2 is putting out 160w, and the mccormack 375w so the difference in bass is not surprising.

I do like the aleph 2's quite a bit. Strong bass just doesn't seem to be one of their characteristics.

I had a long discussion over phone with Passlabs people and they reckon and strongly suggest that even a 1,000 ohms output impedance out of any preamp will not upset the Aleph 1.2 whose input impedance is only 10,000 ohms provided, a quality interconnect like Cardas "golden ref" is used. Yes - the extra warmth of the cj might be too much. I was speaking to another ultra highend specialist who suggested the FM Acoustics new resolution series 155 preamp to go with the Aleph 1.2s. I do know that FMA gear is very neutral, typical of the swiss and they practically thrive on 'neutrality'. Wonder, how this would match? The FMA 155 also have quite low output impedance, typically around 100 ohms.

Also, may I clarify that the Aleph 1.2s I am talking about are 200 watt monoblocks at 8 ohms. These are the flagship ones of the entire Aleph range of amps.

John_l,
Restating what I said previously, I agree that if you are looking for bass slam there are many better choices other than the Pass Aleph amps. A good example would be a Plinius amp. They have such an iron-fisted quality that is almost shocking in their impact. But, having owned a Plinius, I know that, even when just considering the quality of these two amps in the bass alone, the Aleph will give you far less slam, but much more extended, much more tuneful bass than will a Plinius. Considering the McCormack DNA 1: Yes, it has much more bass slam than the Aleph series, but if you audition both side-by-side with speakers and electronics which do a good job of reproducing the entire frequency range, I think you will find that there are few amps if any which exceed the Pass Alephs, particularly the larger ones, in bass extension. Then, when you look at these amps in their entirety, versus the McCormack DNA 1, for example, with regard to high frequency extension and detail, soundstage and neutrality, I don't believe you could rate the McCormack in the same league with the Pass Aleph. I am not disparaging the McCormack. It is a very good amp and an excellent buy when you take into account its price point. But as good as it is, it is an amp built to a price point. IMO, the Alephs are built to compete with the best available, even if they don't offer the best bass slam in the business.