Danny, what are you using as a transport, and has it been modded?

Danny,

Is the mod to the dAck! difficult to do?  Can someone with very little soldering skill perform the mod?

Andy

Yea the Mod to the dAck was pretty easy. Just de-solder a couple of caps and solder in the new ones. All was pretty easy to get to. I couldn't use my big solder gun though. I had to use my small tipped soldering station.

The Sonicaps are also slightly less expensive than the Auricaps. Even with the .01uF by-pass caps they may still be cheaper.

I am sending some to Chris for him to try. If he likes them too then they might become the new standard in the dAck.

Jack,

I think Danny mentioned that the Sonicaps sounded better than the Auricaps (though with different values).

This is very interesting.  I've got a Scott Nixon TubeDac on its way to me.  Hantra made a point in another post that the dACK uses the TubeDac circuit board and adds a battery power supply.  I've also heard from the former owner of my TubeDac that a Siemens tube (which he also sold to me) sounds better than the stock Sovtek.  Should be fun!

I think Danny mentioned that the Sonicaps sounded better than the Auricaps (though with different values).

I guess a better way of asking my question is "how much of the difference would you attribute to the difference in values?".  Also, I tried a Scott Nixon DAC on my system a while back.  Although it sounded very good, I can't say it sounded better than my Smart DIO.  Perhaps my system (which has since changed) had better synergy with the DIO.  Anyway, I hope to hear the dAck one of these days.

J

Thanks Wayne.  I hope to get on the list of auditioners (is that a word?) for the Mensa/Bybee pack.  Hopefully, we can also check out the dAck and do a side by side comparison.  I totally agree with you about personal preference.  These designs are very different and seem to offer (according to Danny's description) very different presentations.  It usually boils down to personal preference.  

Thanks,
Jack

I tried a Scott Nixon DAC on my system a while back. Although it sounded very good, I can't say it sounded better than my Smart DIO

Jack:

What was your system at the time, and what is it now?

Did you happen to have any Bybees in your system at the time?

B

Even though there are obvious similarities between Scott Nixon's DAC and Chris Own's dAck, I don't believe there are as alike as you think.

All I'm saying is the DAC was first built with Nixon's DACKit boards.  If he now has his own boards, that's great, but the similarities have to be startling if they are based on the DACKit. .

B

Well it looks like Danny beat me to the punch with a review of the Bolder Cable Company modified ART DI/O and the Chris Own dAck.  For the record, my comparison consisted of the Bolder MENSA modified ART DI/O (a step up from the SMART DI/O unit Danny listened to) and stock dAck unit (Danny modified the caps).  

I used the Bolder Cable M-80 cryo digital cable, but kept my Groneberg Quattro Reference IC's in for the comparison as I preferred the sound compared to the M-80 interconnects.  My system is listed in the system section.  An extensive listening comparison of ~ 30 hours total during the last week was performed, in between yard work, fall cleaning, and completing my "honey do" list during the second week of my summer vacation.

I have to say that in general, my observations are very similiar to Danny's with a couple of exceptions which I'll note below.  Suffice it to say, these two DAC's are simply put "great products which offer cheapskate audiophiles a chance to step into the big leagues of digital sound reproduction with a decent transport or dedicated CD player."

My extended listening test were also completed on Saturday, as a Sunday listening session with fellow Audio Circle members vanished with various scheduling conflicts.  

My listening was done in system using my Audible Illusions M3A preamp as well as DAC's link up directly to the DNA LA-100 (Don Nance modified ART SLA-1).  BTW, this is a very nice amplifier which I'll be posting additional comments about shortly.  I generally listened to a full CD using the MENSA then switched out for the dAck keeping sound levels as close together as possible with a RAT Shack decibel meter.  

As previously noted and oberved by Danny, the inline bybee is the real deal.  I found it performed best with the MENSA unit more so than with the dAck.  In my system, I felt the stand alone dAck w/out the bybee filter sounded a bit more realistic.

MENSA Observations

Includes MENSA unit and Waynes special power supply w/ intermittent use of an in-line Bybee filter.  

Fully agree with Danny's comments - a huge improvement over the stock unit and his services are highly recommended. The audition kit with in-line bybees, M-80 cryo and standard cables and three types of power cords provided for an almost Christmas like atmosphere in my listening room.

The in-line bybees added more smoothness and increased detail.  A four thumbs up rating        
Same for the nitro power cord.  I have been using the type 1 and type 2 cords in my system for over a year.  The nitros, well they are a major step up.  Hearing is believing.

With Wayne's power supply the unit has a low noise floor and much better sound than the stock power supply provided with the ART DI/O.

The end result - a very detailed and resolving sound that had me thoroughly engaged in all types of music - jazz, orchestral, pop, etc.  An extended airy treble combined with a deep, clear powerful bass response.  These are two areas where I thought the MENSA bettered the dAck, keeping in mind that my dAck unit has the stock caps.  As previously noted, the in-line bybees just made things better, a touch smoother, more refined, and quieter.          

dAck Observations

The dAck is a simple unit, just a nice stainless steel case and battery charger.  I should note that charging the battery after use was simple and did not eat into my listening time.  I had the unit on a couple times for extended listening and break in (12-14 hours straight).  During these lengthy periods it took no more than 1 hour to fully recharge.  Shorter listening sessions took 10-15 minutes.  

Out of the box the first thing one notices about this DAC is what is lacks - any noise.  This is absolutely the quietest piece of audio gear I have ever heard - or more accurately not heard.  This created an almost eerie listening experience, especially in the late evening or early morning, and imparted a very special quality to the music.  

My only complaints about it before was the top end seamed a little soft and it lacked a little bit of detail in the highs. I also thought at times that the bottom end seamed like it lacked a little extension or tightness when compared to the bolder modded DI/O too. Not much though.

The sonic signatures of the MENSA and the dAck are different.  On vocals, jazz, and pop recordings the dAck has an edge on the MENSA unit.  With vocals in particular, the dAck invokes a special quality approaching some of the very finest vinyl playback (my personal reference) that I have ever heard in the digital realm.  This is the first time I have ever heard digital playback in my system approach the quality of a top notch reference vinyl recording.  I also have to give this unit four big thumbs up        

I moved into orchestral and opera recordings, the dAck exposed its weaknesses IMHO.  The highs simply did not match the extension and clarity of MENSA.  I my deep bass torture test, in went the Gladiator sound track, a couple of organ recordings, and some classic orchestral pieces.  While the MENSA excelled with a deep, quick, and clear bass (w/good distinction between instruments) things got a little murky with the dAck.  

I think that Danny's cap modification to the dAck accounts for differences in our observations about this unit.  Any observations from Danny, Chris Own or others would be welcome.  

Round Up

That said, I am at a bit of a loss to say which DAC I liked the best.  To my ears the MENSA sounded more tonally accurate across the full frequency spectrum - maintaining a cleaner and clearer deep bass and upper treble response.   If you listen to a lot of classical music, this may be the DAC for you.

If you listen to jazz, vocals, or more intimate music the dAck may be more to your liking.  The dAck's no over sampling, no filtering, battery power, and low jitter design really imparts a special quality to the music.  If the deep bass and treble response can be improved with different caps, I would be hard pressed not to recommend this DAC to anyone - period.

I also agree with Danny's observation about the dAck.  Listening to it reminded me of when I first heard a good tube amp (Quicksilver) with Vandersteen speakers.  The glorious mid-range just "sucked you in".  As Danny mentions there is something to be said for a simple design.  Vocals got lush, gooey, smooth, and really natural. Vocals had no sharp edge and could be listened to for hours.

Others may get a different opinion from these two units, me I am hoping Chris Own will incorporate the cap changes recommended by Danny as I view his product "almost sonic nirvana but just needing a tighter, cleaner deep bass and more extended treble. "

Again my congratulations to both Wayne W. and Chris Own for not only making some great products, but also providing an opportunity through the MENSA audition kit and dAck in home trials for folks to listen to these top notch DAC's in their own systems where it really counts.

Chris Own dAck
 
http://ack.dhs.org/

Wayne W. Bolder Cable Company  

http://www.boldercables.com

FYI, your mileage and listening pleasure as always may vary.

Hi Folks,

Thanks to all of you who have given kind words about my product.  I'm glad it has been received well.  

This'll be my first post on AudioCircle - I usually don't like to do too much talking and prefer to let the product speak for itself at in-home auditions.  However, there are a few things that I wanted to clarify or comment on, because some myths seem to have been propagating about the dAck! and this Sonicap thing has been getting a lot of attention.  This'll be my one long message.


1. Mix-up with Nixon's unit:

The Nixon unit is similar to the dAck! only in that it is a non-oversampling DAC and that both are aimed at the extreme value market.  The dAck! uses a dedicated PCB that is completely dissimilar to Nixon's unit and is engineered from the ground up.



A very early development revision of this converter used Nixon's basic board as a platform on which to perform the fundamental conversion operation.  The basic circuit of all digital filterless units is roughly identical, and Hantra may have seen a photograph of the Nixon unit being used in this capacity during the early development stages.  There's a hell of a lot more to digital design than tacking on a pair of batteries!

The Nixon DAC and dAck! follow extremely different design philosophies and, in an absolute sense, are not in the same playing field.  I do not agree with Scott's method of grounding, the way he throws Black Gates at the problem, and his method of supply decoupling.  The receiver and DAC chips are different from those in the Nixon units - the TDA1545A is a continuous calibration unit similar to the venerated TDA1541A DAC used in many of the best CDPs and DACs in the past.  The Nixon DAC and dAck! do not sound much alike, other than that they share that special non-oversampling midrange.


2. Some technicalities:

It is not surprising that the Bybee made little difference with the dAck!.  Non-oversampling units will be quite insensitive to timing errors in the signal.  Digital noise rejection with the dAck! is about the best you will find anywhere, which allows users to spend less on transports and expensive cables (and filters) while maintaining the same level of performance, and use the excess to buy more music!  Of course, it always helps to have the best datastream you can get, so a multi-$K transport is not out of the question.


3. Will it work in your system?

Feedback from customers has described a noticeably specific trend.  The dAck! loves music-making systems.  Tubes are a big plus, as is generally PRaTty gear, such as Dynaudio, Merlin, and NAIM.  Analytical systems (for example, Levinson/B&W) will restrain the dAck!'s abilities.  Danny makes speakers voiced for music, and Dodd's amplifiers are top-notch in the musicality department.  That review system is one of the best systems one could hope to put the dAck! into.  


4. About the Sonicaps:

Danny wanted more in the high frequencies so I suggested to him  that the decoupling could be changed out for Sonicaps.  During the design of the dAck! long ago, I got a pair from Danny and I had found them too hot on the top.  The circuit has matured and with all the interest in the "mod", I will definitely be re-visiting them.  I knew he liked their response and that they would tip up the HF's in an acceptable way, so this was the obvious thing for Danny to try.  

The bass performance of the dAck! is optimized for preamplifiers with input impedance in the 10's of Kohm or higher.  Danny's system plays extremely low, so he is really pushing the limits of the stock capacitor's specs.   Most people who are going to spend $400 on a source component don't have -3dB at 30Hz like those wonderful Alpha LS.  In the low bass, it is easy to detect a couple-dB shift in bass, and the listeners definitely heard this in their comparison.
 
The stock capacitor is specified with the constraint that the -3dB point must be nominally 15Hz for a 5kohm input impedance in the average production unit.  In the worst case scenario, it will not surpass 20Hz, however, the rolloff of course begins in the audible range.  If you use a high-input-impedance tube preamp, you should have little concern about the bass; if you use a poorly-designed SS unit, you *might* run into some roll-off problems, but probably not.  In general, the 3.0uF value Danny used will give a bit better bass response, especially in systems with really, really deep extended bass like Danny's.  

With D/A's that are flat to almost DC, the dAck! cannot compete.  However, it was not meant to (see topic 6).


5. dAck!s with Sonicaps?

Several of you have inquired about the issue of dAck!s "upgraded" to SoniCaps.  I value very much Danny and others' input on the matter of the capacitors, but I can't change the product if I haven't had a chance to properly investigate their effect.  The sound of the dAck! is a synergistic whole of the design process and each component was carefully voiced to give a balanced listening experience.  Adding new capacitors will require rigorous testing of both short-term and long-term effects.  I will be able to say more in a few weeks and I'll keep everybody posted both on my website and on this forum.

Review readers please keep in mind that analog cabling can easily alter what you hear through the system.  I voiced the dAck! using a silver tri-braid cable similar to the Kimber KCAG.  Quite extended highs without being forward, midrange detail without fault, and excellent bass.  It's a lively cable, and may be quite different from what Danny is using.  Some of my listeners think the dAck! is hot, some think there is not enough detail.  It's up to you to decide - but remember, you have some control with those little wires that go out from the source and into your pre.


6.  Regarding the high frequencies:

The unit is voiced for midrange performance.  Being from a musician's background, the tonal texture and harmonic structure of the sound is of utmost importance.  I was a musician before an engineer, and listening always takes precedence over measurement.  Correction of the high frequencies using an analog post-filter results in some phase distortion which completely alters the soundstaging and transient dynamics.  The dAck! is the champion in midrange detail, and I will never compromise that for enhanced high frequency response.  The latter is overrated in this field.  You can continue to push the high frequencies up, but you will continually lose magic in the midrange.  This is a compromise you have to accept with non-oversampling.  

Additionally, the dAck! was designed for vinyl lovers and was intended to be quite similar to that of the best vinyl reproduction.  In addition to the "glare" you hear in conventional digital audio, the HF of high-end digital reproduction always contains an artificial air and ambience.  This is quite well-documented and a widely-accepted digital artifact.  The fact that this is not present in the dAck!'s playback sometimes makes strict CD listeners feel like something is missing (it's true of course!).  However, vinyl listeners never complain about this; in fact they welcome that it's gone from CD playback.  The high frequencies are rolled off - that is an artifact of non-oversampling that I specifically have not compensated for (see Stereophile measurements of Shigaraki DAC) - but also some of the perceived loss of high frequency you may hear people talk about is due to this lost artificial "sparkle" in the highs.


For those intrigued, when you get the chance to listen to the dAck!, the first time go ahead and listen for those classic things such as imaging, frequency response, and detail.  But keep in mind that this is a different ball-game - this is design for long-term listening satisfaction.  If you do become an owner, I wish for you not to sit there analyzing the space around instruments and checking if you can hear those lowest organ fundamentals every listening session.  I want it to accompany your day-to-day activities.  I want it to keep you up late at night because you want to put in CD after CD.  I want it to always give you goose bumps when that soft voice begins to sing.


Best,

Chris
Ack!Industries