Today I had the pleasure of listening to Tasos' system again. As readers of this thread will know, Tasos modified his Berkeley Alpha DAC 1 in several steps (I have a Berkeley Alpha DAC 2 myself, but in standard condition). The first time I had listened to his system, about a year ago together with Peter A., I had been impressed with, among others, the speed and dynamics of his sound, but had noticed some aggressiveness in the treble that back then I attributed to the room acoustics. Apart from modifying the DAC and changing toe-in of the speakers somewhat, there were no other changes. On the analog side there were (stabilization of the arm with magnets), but we did not listen to analog today, as Tasos himself hadn't done as well since the last modifications of the DAC.
I had not expected to hear what I did hear. Any aggressiveness of the treble was gone, despite the fact that room acoustics had not changed. Not just that, the treble was exceptionally clean, and extremely highly resolving. The treble register of the piano might have been the best I have ever heard from a system. So much purity, resolution, speed and clarity, unbelievable. It was just effortless. Imagining what you heard in time lapse you could savour every detail of attack, sustain and decay. I was asking Tasos if he had switched the setting on the MIT speaker cables from HD to SD because, after Peter and me hearing the system on the HD setting, Tasos said that he had discovered the system sounded much cleaner on the SD setting. Yet a few days ago he had switched it back to HD, because now with the improvements in the chain he thought HD was better. So I heard it with the same setting as a year ago. But the sound was completely transformed. All that from just DAC modifications?
While in the beginning we were talking about different things, a jazz CD had played in the background. I noticed that the cymbals sounded really good, and asked if I could hear the music at realistic volume. It sounded great, and I also played a jazz CD of mine. Cymbals had a very similar tone color as on my system, but the sound was even better resolved. In fact the cymbal sound was so well resolved in every micro-detail that it was just stunning. And that from "just" a Berkeley Alpha DAC! Modified though by Tasos, which made all the difference, apparently. But I digress. I wanted to say that I have found that it is very hard for an SS amp to get both sheen and body of cymbal sound right, something that very good tube amps are excellent at. But the Spectral amps could do the trick as well. If I remember correctly, Keith Johnson once said that Spectral wanted to emulate the strength of tubes, but then in a high power, high current setting. It seems they have succeeded big time with their latest amps. I was a huge fan of Spectral before, but my esteem of the brand has been raised another mile after today. If I could afford it I would certainly buy the SS30SV pre-amp/DMA-400 power amp combo that Tasos has (including mandatory Spectral/MIT cables). Or instead of the DMA-400 monoblocks the 300RS stereo amp that also greatly impressed me earlier this year.
Next thing was flamenco guitar. This was, by a large margin, the most natural and realistic sounding reproduction of classic acoustic guitar with nylon strings that I have ever heard -- it was jaw dropping. And that from Redbook CD digital! Tasos thinks that his DAC now sounds analog, and I agree. But even from analog I have to date not heard such acoustic guitar. Acoustic guitar with steel strings seem to be easier to reproduce, but nylon? Wow. We went to listen to another guitar CD, the famous Al Di Meola/Paco Di Lucia/John Mc Laughlin live CD. I had been impressed by the reproduction over Tasos's system before, but this was on a whole other level. While last time the guitars had sounded more similar, now you could easily hear the different types of string employed by the three guitarists. And it sounded so clean! Also, transients and dynamic snap were incredible, the reproduction was just dripping with liveliness. The three terms that I kept coming back to when describing the sound from any music that we played was "fast", "resolution" and "dynamic" (with dynamics meaning both micro- and macro-dynamics). Personally, I am a dynamics freak, and thus I immensely enjoyed what I heard.
We heard several brass recordings. One was a Dorian sampler, with the James Bond theme and the Pink Panther theme. Outrageous transient speed, outrageous dynamics. I wonder how horn systems could even improve on this. Another recording was one that I brought, Hindemith's concert music for brass and strings (on a Decca double CD with Herbert Blomstedt conducting the San Francisco Symphony). It sounded great, with good body in trombones, horns and tuba. This wonderful recording sounds with high resolution on my system, but on Tasos' system there was perhaps even more timbral resolution. Also separation of instruments was outstanding, even though, due to room constraints, the soundstage of Tasos' system is not very large. And maybe here and there I heard some lines that I do not even hear in my system -- I'd have to go back and check. In any case, it was impressive. Separation of instruments was also great on Mahler 2 (Ozawa/Boston Symphony) and so many other recordings.
Dynamics on the Hindemith were just as good as in my system, and transient speed was again to drool over. Violins sounded wonderful, and in one soft passage perhaps even sweeter than in my system. -- In general the bite of brass, grouped or solo, was great, something that is very important to me. I cannot stand unrealistically 'polite' sound, and the bite of brass on Tasos' system did not disappoint, and it was not marred by artificial hardness either.
Bass was of very high quality. It was tight where it should be, but of appropriate roundness when required as well, e.g., with solo stand-up bass (there was no artificial speed of bass). Bass went deep, integration of the main speakers with the sub was excellent. Tasos has extensively modified his Martin Logan speakers with great expertise, and there is a seamlessness between panel treble and midrange and cone bass that you hardly may hear from any standard Martin Logan model (lack of integration within the frequency range is an all too common complaint).
Organ was majestic, and I noticed that organ bass, while very powerful, had a lot of the airy quality that you hear live but the reproduction of which at home is so elusive. Also orchestral double basses had an appropriate airiness to their sound.
In some instances decay seemed to go on forever. Be it from piano, solo strings or other instruments, decay had a convincingly natural quality that was enormously impressive. And again, all from mostly plain Redbook digital (with a few HDCDs thrown in).
Great recordings of human voice sounded very natural, even intimate in some cases. Sibilance was perfectly controlled, again a result of flawless speed of source, amps and speaker panels.
Another CD of mine, the HDCD of the debut of the Janaki string quartet, produces some of the highest resolution from my system. Yet as expected, Tasos' system went even further. There were micro transients on the violin bowing that were simply astonishing. The Beethoven trio sounded beautiful, and the first violin entrance on the Penderecki (at about 1 1/2 minutes) was shredding just as it should be, and as it is also on my system (there must be no smearing and softening of transients).
After hearing all this superb reproduction from low bass through midrange to the high treble through the extensively modified Martin Logan speakers, effortlessly driven by the Spectral amps, I am starting to wonder, like Tasos does, if for example switching to Magico M3 speakers would improve the sound in any way. Perhaps when it comes to imaging, but in other areas? I am not so sure. Yet even imaging seemed considerably better than last time. Also, unlike last time, the sound did not change much if you sat in the sweetspot or on the side of the couch; possibly the different toe-in helped. Last time I preferred the less aggressive sound more on the side, but today I listened to the aggression-free sound in the sweetspot for hours without fatigue.
Congratulations, Tasos, on a great system that reproduces music in such a lively, exciting and involving way!
. BTW, I haven't heard yours but I have heard theirs and although the real thing is not produced as we all know I can promise you that you will not feel closer to the larger scale presentation than hearing their presentation. 
