[JoshK]

Chris,

Let me be the first to welcome you!  And further, that is a great response with the kind of real information that we here at AC thrive on. Thanks much!

Josh

[JoshK]

Oh...forgot to ask.

Chris,

I hope you read this, but it was asked if the DACk could be made to swap out spare batteries so one could be charged while the other was playing.  Any idea on whether this could come about?  Or use of Lion type battery.

[byteme]

Great to have you aboard!  thanks for clearing those things up and for the explanation.  Very informative.

[Sa-dono]

On behalf of Audio Circle and the 2-Channel Audio forum, welcome to the forums Chris! It's always nice to be able to get information straight from the source..so I hope you stick around and continue to contribute

[markn]

After reading Chris's post, I have to agree - the Dack! is high in the Goose Bump category!

I have already place my order!  Since my system consists of GR-Research speakers and Dodd audio electronics, I expect similar results at home...

Mark

[csown]

Thanks, guys, for the warm welcome.  

Josh:

The battery discharge schedule for the dAck! is intended to give you the best life out of your batteries.  I designed the dAck! primarily for vinyl lovers and those people are quite accustomed to being very interactive with their systems.  4 hours is the manufacturer's (my) recommendation: a nice medium between weight, performance, longevity, interactivity, and not to mention those cells fit perfectly inside the chassis so you don't need some bulky outboard thing to power the dAck!.

How you use it is up to you.  With the high-quality cells provided with the dAck!, you can expect about 800 charges if you use the 4-hour discharge rate.  This means your batteries will probably last you about 1.75 to 2 years if you listen like me (I listen 50/50 vinyl/CD and listen a lot on weekends).  If you use it for 8 hours each time, you can expect a little less than half of that many charges.  That means 300-400 charges is realistic.  That is still a good year or more of life out of the cells.  This is the same lifetime as a good set of small signal tubes or your typical high-end phono cartridge.  Keep in mind that this is all theoretical - the dAck!'s power consumption depends on the kind of music you play through it.

You can treat it like you would a very nice set of tubes:  Those expensive 300B's you don't necessarily want on all the time, but sometimes you leave them on overnight because a little extra toasting every now and then won't kill them.  And some people who prefer to live dangerously just let them cook all the time.  Analagously, running the dAck! for 10-12 hours every now and then won't kill it, but you can expect the batteries to have slightly decreased life every time you do this.

Regarding lithium ion, there are a lot of reasons why they are sub-optimal in this sort of application.  They are really designed for ultra-portable high density applications, not for providing basic day-to-day power.  You don't see that many life support units or security systems running on Li-ion cells, do you?  Here's just a quick list of why they don't work so well in this application.

The voltages available are weird and are targeted for portable equipment.  The amplifiers used in the dAck! can't go above 13V, and SLA's run comfortably right up to the limit.  No combination of 3.6V Li-ion cells is very optimal here.

The voltage changes in Li-ion cells as you discharge them.  As a consequence, your biasing conditions will change dramatically over the course of a few hours.  Not good for picky hi-fi listeners.  The swing can be between 4.3V and 3.0V.  That's huge!

They require fairly special charging conditions controlled by a CPU to get the best life out of them.  This means $$$.

The basic discharge schedule for highest longevity means that they should be discharged and charged often between 50% and 90% capacity.  Depending on how you charge it, charge to 90% capacity can be quite fast.  Topping off from 90%-100% usually takes about 2 hours, so you never get maximum capacity.  Additionally longevity is decreased if you top it off all the time.  This doesn't jive with the hands-off always-charging-when-off paradigm of the dAck!  If you think about it, it's really counter-intuitive - cycling your laptop constantly will give you a similar battery lifetime to the case where you keep it plugged into the wall all the time and rarely discharge it.

They can't be stored for more than 2 years, have to be stored at ~60% capacity, aren't very shock-proof (except for polymer type), and are expensive.

Best,

-Chris



*** 082603 5PM Edit ***

A few people have inquired about the *least* amount of time you can use the dAck! for.  Short spurts are perfectly fine and will give you more charge-to-full cycles out of the cells.  A lot of times, I'll come home from work, listen to 1 CD, then head out to dinner.  No problem with that type of listening.

The dAck! is designed to charge whenever it is off, so when you're not using it, the automatic charger is either charging or conditioning the batteries.  It should be 100% dummy-proof - when you want to listen, turn it on, when you are not listening, turn it off and the system takes care of the charging details for you.

If you want to do critical listening, give it at least 5-15 minutes to stabilize (assuming you have been using it at least a few times a week).  If you are really picky, an hour and the power supply should be quite stable.  Battery supplies stabilize a lot faster than your typical AC/DC supply, and a hell of a lot faster than high-performance AC/DC supplies, which (as many have probably found) can take a day or two to fully stabilize.

[peakrchau]

....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 ...

Hi Chris,

Good to see our paths cross again in internet space...this time in a forum that I think is ideally suited for your dAck!  There is a Audio Manufacturer's section/circle that you could/should open when the tip of this iceberg of interest turns into (I predict) a floodgate. It is rare that a musician turns engineer...the result is usually products that reach landmark status....witness Paul Barton of PSB and  Bjorn Erik Edvardsen of NAD.

I think you hit the nail on the head with regard to percieved frequency response. With silver wiring the auricap balances off your unit but with the sonicap a less "silvery sounding" cable a la Jon Risch's twisted pair 89259(hot)/82248 would probably due the trick. Have you tried it ?

When I took a look at your circuit board, I couldn't help think what Walter Jung might  say of his early experiments on Philips/Magnavox and his design choices using reasonably priced "Panny" passive devices in early Audio magazine CD modification articles. His goal then was to make digital sound like Vinyl..."what goes around...comes around".  I'm glad you took the "leap" and wish you continued success.

Any word on the chance of a review unit getting into the hands of    Soundstage, Positive Feedback, Stereophile or the Absolute Sound ? Will you be at any upcoming Audio Shows ?

Cheers.

[JoshK]

Chris,

Thanks for your great responses!  And again Welcome!

[Danny Richie]

Will you be at any upcoming Audio Shows ?

Chris may not be at any shows real soon but his dAck will.

I will be taking one to the VSAC show in October:

http://www.vsac2003.com/

I will aslo have one at the 2003 Texas DIY event:

http://www.gr-research.com/diy2003.htm

[Rob Babcock]

One more question about the dAck!; I'm aware that with the DI/O some folks have experienced problems with the unit losing lock when play is stopped.  Does the dAck! have any problems in this regard?  And is it limited to just 44.1/16 bit signals?

Thanks.

[JoshK]

Rob, I am pretty sure it is limited to 44.1/16 signals from the DAC it uses. This is fine with me for CD playback as the best digital I have heard to date was a filterless 44/16 player.

[Danny Richie]

I'm aware that with the DI/O some folks have experienced problems with the unit losing lock when play is stopped.

Mine does that.

When the CD player is turned off then turned back on it can't track and gives you an ear full of what sounds like White noise.

I have to pull out the power supply cable and wait for it to power down then plug it back in.

I have had no such problems with the dAck.

And is it limited to just 44.1/16 bit signals?

Yep, and I think this is the best sounding D/A converter that I have heard.

[Rob Babcock]

Just wondering.  I know there's some good DAD stuff out there, it'd be nice to have a DAC better than the players built-in to listen, but no biggie.

I might have to give the dAck! a shot down the road, got a few things that I need a little worse right now.

[doug s.]

hi peak,

does this mean yure ready to ditch yer di/o now?     i'm strongly considering an audition of the ack! dack!

regards,

doug s.

[Rob Babcock]

I would like to ask one more thing about the batteries: it seems that they aren't really "hot swappable", but is replacement pretty quick & easy?  How long could one keep a spare around before the spare would discharge?

It would be really cool to have a battery pack in it's own chassis so they could be swapped out as easily as the cells in a computer UPS- I'll admit that I don't know if that could be done without compromising the design...

[BradJudy]

I'd be interested to hear what a combination of the battery powered dAck! with a good battery powered headphone amp (maybe a well done META42 or the new DIY craze: the PPA) would yield with a nice set of cans (maybe Senn 600s).  It would seem that this might have the ultimate in low noise floors.  

Heck, some of the Sony CD Walkmans have optical digital outputs (I haven't seen one with coax digital) - mabye you could put together an entirely battery powered digital system.    

[peakrchau]

hi peak,

does this mean yure ready to ditch yer di/o now?     i'm strongly considering an audition of the ack! dack!

regards,

doug s.

To live is to experience new things.  The DI/O requires a lot of work due to its cheezy power suppy, as you know, the improvement wrought by adding additional heavy pieces of iron called isolation transformers can be significant.  Even some of the http://www.audioasylum.com/audio/digital/messages/71269.html">veterans over at Audio Asylum have dropped their jaw line by an inch after listening to the dAck!


In the 80's, there were good examples of audio engineering. Vinyl was king, some low powered amplifier stages for low output moving coil cartridges ran off battery power.  Farad Azima of Mission Electronics extended the idea further downstream and introduced the world's first battery powered pre-amp in the form of the Mission 776. Using Google I just barely found the picture of the unit below at a German http://translate.google.com/translate?hl=en&sl=de&u=http://www.fl-electronic.de/neuklang/cyrushistory.html&prev=/search%3Fq%3D%2522farad%2Bazima%2522%2B776%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3Dutf-8">hi-fi site. An old idea that has resurfaced in the dAcK! and a key element to its sonics.
 

Things have evolved over the twenty somewhat years since Farad introduced the 776, with  major developments in wire technology, discoveries about polarity, better coupling caps and resistors. These items were not yet understood to make a difference....the only thing people agreed upon was the metal film resistors were better than carbon film....and we know in hindsight that this  generlization has altered.

In that era, when you listen through the pops and clicks of vinyl playback...there was/is gold in the grooves that CD playback looses.  The dAck! (have not heard it) can mine some of that gold...it is the rarest of birds gauging from mushrooming attention that it has generated in the last month. I know that DCS has been a proponent of upsampling, but I find most units to have higher noise floors that overall result in a tradeoff with the theoretical advantages of upsampling...some blame it on the potential for higher levels of RFI in the scheme.



P.S. It would be interesting to cobble up a DI/O like voltage multiplier circuit to power the dAck! just to see how they would compare with equal footing on raw power.  I suspect the LT regulators used in the dAck! would still offer advantages in a lower noise floor. It is a digital bits converter designed by a vinyl addict....so batteries and a high quality regulation seems to be the required path...what is old idea has resurfaced....all it took was twenty years and a couple of crtical ears.

[nature boy]

Danny and other dAcK! enthusiasts,

After additional extended listening to the dAcK! in my full system, with the Audible Illusions M3A preamp, my slight hesitation about this DAC (see my post on this thread) has been vanquished.  As previously stated, I am biased to a natural sounding mid-range and vinyl reproduction. This non-oversampling DAC does natural reproduction of music like nobody's business.  My overall rating has been increased a top - FIVE THUMBS UP        

I am not sure if it is the synergy of the tube preamp, additional burn in of electronics in the dAck! or my Don Nance LA-100   , but the bass on Gladiator and large orchestral CD's really tightened up this morning.  The drop ceiling tiles in my listening room were hanging on for their lives.

That said, I will be interested in hearing Chris Own's comments about the dAck! with the Sonicap substitution for the Auricaps in this unit.

At a price of $395 + shipping and the in home audition, the dAcK! has to be one of the best audio values I have found.  It's got me listening to CD's again, something I never thought I'd say, as a dyed in the wool vinyl lover.

Now, if Chris would only offer this unit is a basic black box to match my other equipment   .......

Happy listening all you audio circle fans and have a great Labor Day weekend.  My "honey do" list and yard work is done, so I'll be doing a lot of listening and grilling.

NB

[peakrchau]

What a difference a couple of days can make...break-in at work? In your http://www.audiocircle.com/index.php?topic=4335.msg36727#36727&highlight=#36727">previous comparisoo with the Mensa DI/O, you said:

....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 am  ...

If the improvement was due to the AMP breaking in , then putting in the Mensa back in should result in things being overdone (as they were fine before) with too full a bass and shouting highs? If it sounds fine, then I would think the it had to due with the dAck! breaking in.

[Rocket]

hi guys,

probably going to be beaten to death but.

all this breakin talk is over exaggerated.  it usually takes about 10 hours to break in a product and there after i cannot hear any improvement.

may'be i need to go to the doctor and have my ears syringed out with clean water  .

it could well be that you were used to the sound and just started to like it.

regards

rocket