ack's system - end of round 1

[ack]

Berkeley Alpha power supply modifications

This is the latest round of DAC modifications, this time around the power supply, using Mundorf Mlytic AGs, which offer exceptionally low ESR and ESL. The DAC was definitely struggling with very large scale program before, like the Mahler 2's Finale, where the chorus had a bit of grain, the soprano was kinda shrieking, etc... More details on the sound later on, but for now, I will make a rather large claim, that this DAC/transport has now probably reached or exceeded the previous generation Spectral SDR-4000SL in performance... which means, I expect the 4000SV to outclass it. On the same Mahler Finale, the Rossini was still better, with more authority with the organ, and in general, offered a larger scale presentation.



This is a rather involved modification due to the tight space and low board clearance, but after 8 hours and a lot of planning, it worked. Just making the cables took a long time...

 

[steve williams]

offered a larger scale presentation.

ahh so we don't need to go to Manila or to Cedar City. We can all come to your house and hear a larger scale presentation . 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.

 

[ack]

I love sarcasm, I live by it! But if you read carefully, I said the Rossini offered a larger scale presentation, not this DAC. At the same time, I don't view audio as "competition", rather an enjoyable journey. But if anyone is going to tell me their system is "darn close" to true-life large scale, I lose interest rather quickly - as I said elsewhere, we just can't record such scale, so let's start from that point.

 

[steve williams]

Ahhhh but now you change things and say "we just can't record such scale". Before you said there are no systems which can do it convincingly

 

[ack]

I don't think I am changing anything. I said there is no system that can be "darn close" to true life scale, and ALSO how can anyone make such a claim when the beginning of the chain is the first [and not the only] limiting factor. So start from the beginning.

 

[steve williams]

too early in the morning to go toe to toe with you and even though I won't dispute your claim, I am stating that there are 2 systems that I have heard that gets me closer than any I have ever heard large scale productions.I can also say that the room in such a quest is a huge factor. Jimmy's room was the largest and most articulately put together system I have ever heard and most everything he played for us was large orchestral on tape. I have never been so close to the real thing as I was at his house. David also has a very large room which goes a long way to house the Bionor speakers and present large scale productions.

Let's just agree to agree that although what you state has merit what I am suggesting is that these are the 2 rooms that for large presentations convinced me the very most

 

[MadFloyd]

Congrats on your new modifications, Tasos!

 

[ack]

I do think we agree, and perhaps one day I'll get the chance to listen to such systems. But in the meantime, I'll make sure I notify folks here of the next Mahler 2nd or 8th performance at Symphony Hall so we can all go as a group, and perhaps we can have a drink over it all too. The sheer fact that the chorus in the 2nd's Finale can EASILY overshadow the entire orchestra sans organ when they go full-bore, in both body and sheer loudness, should be an interesting if not humbling experience... not to mention the crescendos. In addition, to me, part of "scale" includes the true dynamic expression of each section of the orchestra, and I have yet to hear winds, for example, sound "darn close" to real in any system so far. But even at a smaller scale, an equally humbling experience is just playing drums - I've heard nothing so far that approaches the impact of a real drum set, such as the attack, high frequency content, body, and just sheer loudness... I've heard "close" approximations in PeterA's system, and though exciting, still too far detached from true life.

 

[ack]

I have doubled the power supply caps from the original modification, as shown below, after careful listening with large orchestral and especially organ. I feel comfortable in saying that the transport/DAC is now far superior to the older Spectral 4000SL. The increase in low-end control, freedom from congestion with complex material, and increase in dynamic headroom over what came out of the factory is just staggering. Coupled with the noise reduction in the output section, this is really a totally resurrected DAC, and I can't stop listening to digital.

CAUTION: Don't try the power supply mods at home if you don't know what you are doing, and space is extremely tight; also, the current draw is now probably significant enough to create fireworks and destroy the power supply, if you accidentally short things; and you probably have to increase the fuse's rating, and I simply bypass it - dangerous any which way you look at it, but I know what I am doing.

 

[Al M.]

I have doubled the power supply caps from the original modification, as shown below, after careful listening with large orchestral and especially organ. I feel comfortable in saying that the transport/DAC is now far superior to the older Spectral 4000SL. The increase in low-end control, freedom from congestion with complex material, and increase in dynamic headroom over what came out of the factory is just staggering. Coupled with the noise reduction in the output section, this is really a totally resurrected DAC, and I can't stop listening to digital.

CAUTION: Don't try the power supply mods at home if you don't know what you are doing, and space is extremely tight; also, the current draw is now probably significant enough to create fireworks and destroy the power supply, if you accidentally short things; and you probably have to increase the fuse's rating, and I simply bypass it - dangerous any which way you look at it, but I know what I am doing.

Congratulations on the success of your modifications, Ack!

I assume the Mundorf caps are considerably larger than the old ones, making the space constrictions even more significant. My tube amps were also modified with Mundorf caps (silver-in-oil), and the bottom plates cannot be screwed on anymore (doesn't really matter).

 

[ack]

Congratulations on the success of your modifications, Ack!

I assume the Mundorf caps are considerably larger than the old ones, making the space constrictions even more significant. My tube amps were also modified with Mundorf caps (silver-in-oil), and the bottom plates cannot be screwed on anymore (doesn't really matter).

You can tell the size difference in the pictures in post #221 above - quite larger indeed, and recall, Mundorf uses double caps inside to get the low ESL and ESR. I'll have you over next week, just need to find the time. Right now, I need to install a small fan to circulate air inside.

 

[Al M.]

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!

 

[BMCG]

Impressive coupling of topology changes with perceived sonic/aural shifts. Some great research and development...remarkable. Congrats.

 

[ack]

Thank you Al for taking the time to write all this up so well, and I am glad you enjoyed it! Six hours went by really quick. And thanks BMCG!

I have a few thoughts to share:

MIT speaker cables, SD vs HD: I wrote a while ago in these pages that SD is it for me. Apparently, as it now turns out, HD was simply exposing and accentuating sonic deficiencies upstream, and once these are cleared, the HD setting with these extra F.A.T poles works just fine and also as advertised: life-like transients. Moreover, the treble cleanliness (especially the metalic cymbal character) & treble dynamics that you heard are directly attributed to it, and not properly corrected by the SD network - I should have demonstrated this, it is quite easy to tell. Treble dynamics are particularly hard to render correctly by any component.

Can digital sound like analog? Great analog is undoubtedly high resolution and can be spectacular and lifelike. Digital has theoretical limitations (e.g. see square wave response measurements), but there is now convincing evidence that it is also fundamentally capable of equally spectacular analog sound, even lifelike; and the higher the resolution, the more lifelike it is. Digital theory aside, a huge part of getting digital right is in the implementation, and it's very hard to do so.

Is RBCD enough for great analog sound? My conclusion at this is point is a resounding Yes, but the implementation is hard; and again, even greater resolution will give you even greater sound - case in point, HDCD and the alleged 18-bit virtual resolution that we heard. I would really love to play some true 24-bit hi-rez PCM now through this Alpha, but USB is currently the limiting factor. I personally find digital implementation extremely challenging, perhaps as challenging as analog circuits; for one, a DAC must implement both digital and analog correctly to sound great, and must be driven by an equally competent digital source.

My current digital font-end: Despite my Alpha modifications, if you look closely at the DAC, it is a very competent design and execution, though not state-of-the-art. The modifications take it to many higher levels, as you heard, and the need for them became apparent only with the current "Spectral Lab" of amplification (aka 30SV->400RS). Moreover and as discussed, I feel it also surpasses the Rossini that I had at home, in certain areas. At the same time, to get this level of performance, the extra-ordinary Spectral SDR-3000 transport is a big part of this, and I continue to seriously doubt that any computer-based digital feed can possibly come close, certainly nothing with USB written anywhere near it. And mind you, this transport must have been designed over 20 years ago?!??!?

How does the transport affect things? For starters, I'll just point you to the Lampizator folks' own technical assessment from a while ago at http://www.lampizator.eu/lampizator/TRANSPORT/CD_transport_DIY.html and what they think competent is or not; the conclusion is as follows: "And now something really good: Audio Note Transport 2 - one of my top picks! ... [redacted]... And finally - what is believed to be the BEST TRANSPORT IN THE WORLD - but not the bullshit kind like marble tumb, but real meaningful honest engineering: Spectral SDR-3000 from USA based on modified VRDS Esoteric (teac/sony colaboration) transport." Here, I would add that MBL transports may in fact be even better.

Note decay with digital: Simply put, if you lower the noise floor enough - and that, again, implies solid implementation - I don't want to hear that digital cannot do note decay, including proper treble decay. If I have ever said this myself, then I stand corrected.

What do I think about the "Spectral Lab" and the new SDR-4000SV: Until I am able to tell sonic shortcomings, I will continue calling the 30SV->400RS "straight wire with gain" and leave the "how much gain" debate for some other time. We simply have Keith Johnson and his team to thank for this kind of engineering prowess. Just freaking AWESOME and oh so inspiring. Personally, I have not yet heard such treble resolution and treble dynamics from any other solid state electronics. The 4000SV is an interesting question; I am unable to draw any conclusions based on my recent audition, because it involved the Avalon Compas speakers, and despite the fact they also used the 30SV->400RS, the Avalons are simply so veiled that I could only draw certain aspects of the sound that possibly seemed better than mine, like the body of timpani, but I am not too sure. However, when driving the Rockport Cygnus, things sounded really interesting, worthy of further exploration of the player.

These stat hybrids or Magicos? This has always been a tough question for me; it is even tougher now; and I have yet to hear the M3s sound good, with the same current Spectral electronics, which included the 4000SV. For one, transient speed was not exactly what you heard here, but it might also be the SD setting on the MIT speaker cables that dealers usually use. So the jury is still out on this one...

Finally, I agree with you, this system has vividness and speed written all over it; there is certainly nothing polite about it; 'raw' is probably a most-fitting word. And let's define 'speed' correctly: very fast rise and settling, with no overhang and proper note decay.

Next time, we'll play analog and do some A/B, with the caveat that mastering can never be guaranteed to be the same, or even great.

Such a fun and rewarding hobby, at all price levels...

-ack

 

[LL21]

Ack,

Fantastic summary. I have no true point of reference regarding SOTA analog having heard only a few setups in my time. However, I can say that having spent time with digital setups and doing tweaking (not nearly in your class of expertise), but mass damping, vibration, bits of emi/rfi, looking at power supply side, etc...i have found that my digital has gone well beyond what it was when i first brought it home. And it is certainly not the latest in digital any longer, even if it was at one time heralded as sota in its day.

 

[ack]

Hi Lloyd; thanks. I always admire your low-key way of writing, and I am sure you know quite a bit more than you share. Digital has come such a long way, but like everything else, it takes money, skill and dedication to do it right. I am sure your Zanden stack is well thought-out, much like the dCS offerings, and others. Yet, as you found out, you can go further with tweaks. I feel there is still more room for improvement with digital - heck, we even keep pushing LP analog all these years, still. Happy listening.

 

[YashN]

However, I can say that having spent time with digital setups and doing tweaking (not nearly in your class of expertise), but mass damping, vibration, bits of emi/rfi, looking at power supply side, etc...i have found that my digital has gone well beyond what it was when i first brought it home. And it is certainly not the latest in digital any longer, even if it was at one time heralded as sota in its day.

Same here, requires a fair amount of work, but the digital I now have is vastly superior to what I had in the default plugged-in configuration: recent experiments in reconstructing a USB Connection with filter and ground isolation, together with external input for power and a few other tricks, and building a Linear Regulated Power Supply have made the sound several levels above the default - the sense of space and presence is fantastic. I still have some work to do to reclaim some high-range clarity and definition, but there's not has/glare like before.

The default USB cable which came with the DAC now is un-listenable to me.

I don't think many devices are well isolated (some of the expensive ones are, of course).

I will take up again my AC Filter Box and external 'signal cleanup' circuit too after I'm done with this leg of the experiments.

 

[leyenda]

Ack, congrats on the big achievement. Sounds like the mods completely transform the BADA. Are you planning a step further re the power supply mod by putting the transformer and maybe add shunt regulator in another box and feed the BADA with DC? Too bad I already sold the BADA otherwise this will be a very interesting mod to perform.

 

[ack]

Ack, congrats on the big achievement. Sounds like the mods completely transform the BADA. Are you planning a step further re the power supply mod by putting the transformer and maybe add shunt regulator in another box and feed the BADA with DC? Too bad I already sold the BADA otherwise this will be a very interesting mod to perform.

Thanks! Excellent question. One of the merits of the BADA is that it is extremely modular; as such, the entire power supply board including transformers, the power connector and ground wire come off as one piece, and it feeds the main board and control unit via a single multi-wire cable. Therefore, it would be trivial to externalize the entire power supply and connect it with the main unit via an umbilical (plus ground). There are many benefits to doing that, including better heat dissipation (for now, I have installed a small quiet computer DC fan), but I don't know if there will be any sonic benefits.

One of the original mods years ago (before their Reference) was to install mu-metal between the power supply and main boards, to redirect the transformers' magnetic fields; since then, I saw Berkeley erect a similar wall in their Reference - and for some reason, I never seem to have posted this in this thread. Moreover, there is a large number of shunt regulators already throughout the DAC with the ability to provide ample current and great noise rejection, so without experimenting it will be hard to tell. But the experimentation will be so easy, I might just try it.

 

[MadFloyd]

Congratulations, Tasos. I've only heard your system once and we listened to both digital and analog. I still remember how jaw-dropping detailed it was and its ability to portray intricate details even during busy passages of complex music.

I can't imagine what it must sound like now!