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How does the sound of the Ack! Industries dAck! compare to "X" manufacturer's DAC? (What is the level of performance of this DAC? / Will the dAck! work well in my system?)

Why is my dAck! quieter than “X” manufacturer’s DAC? / How do I properly A/B my dAck! against other converters?

What do I do about turn-on/turn-off thump?

Does the dAck! require break-in / what is the run-in time?

What about jitter? Does it matter for the dAck!?

Will you offer a Toslink or glass input option?

How long can I expect my batteries to last?

Where do I get replacement batteries / Can I buy replacement batteries off the shelf?

 

How does the sound of the Ack! Industries dAck! compare to "X" manufacturer's DAC? (What is the level of performance of this DAC? / Will the dAck! work well in my system?)

We obviously cannot answer this question for every converter on the market or for every system the dAck! might be used in. The Ack! Industries dAck! will likely behave more similarly to other non-oversampling DACs than to oversampling DACs, but it has a unique character that is unlike anything on the market. It is designed to be competitive with DACs in the $1500+ range. Please inquire for specifics.

Why is my dAck! quieter than “X” manufacturer’s DAC? / How do I properly A/B my dAck! against other converters?

While many CD players have monstrous output drives of about 2VRMS, we have chosen to use a smaller output level of 1V (0.7VRMS, or 2V peak-to-peak) for a number of reasons. Firstly, the dAck! was initially designed to complement analog systems. Typical phonostages amplify moving coil signals to roughly this level. Thus, when switching from analog to digital in your system, you will conveniently stay in a similar regime of operation. Additionally, most volume potentiometers tend to operate best at high settings because they are less noisy and the channel matching is better in the higher regime. In most digital systems, a 9:00 setting is already very loud; with the dAck! it will be at 12:00-1:00. For customers using digital-only sources, or those with low gain in their systems (e.g., passive preamps or low-power amplifiers), we offer a high output version that outputs a 2VRMS.

It is well known that in A/B tests, the louder device almost always wins so for an objective comparison it is important to match output levels. To appropriately match levels, put in a test tone CD (broadband noise is preferred but a 1KHz tone is OK). Using the louder source first, measure the output amplitude across the speaker terminals with a voltmeter in AC mode or with an oscilloscope while playing the tone at the desired audition level. Next, install the second source (the dAck!) and adjust volume control to achieve the same measurement. When you are switching between sources, alternating between these two volume settings will give you consistent output levels between the pieces under comparison.

What do I do about turn-on/turn-off thump?

When the dAck! is first turned on, the output capacitors will charge up momentarily as they start to block the DC from the conversion circuit. Because of the speed of the dAck! 2.0 output stage, this thump is more prominent than in the original dAck!. The magnitude of this thump is about 1.5V which is a slight bit louder than the loudest transient that comes out of the dAck! during music playback (less if you are using the high output version). This thump is a low rate signal and will not damage your loudspeakers or electronics because it is about the same as a big orchestral transient during playback. If it bothers you, turn down your volume control slightly before turning your dAck! on or off.

Does the dAck! require break-in / what is the run-in time?

Since the dAck! is battery powered, owners do not have the luxury of leaving it on all the time for rapid run-in. On a new dAck!, the capacitors need to form the dielectric and there is some diffusion that occurs in the semiconductors. A new unit should stabilize within about 2 weeks (~2-4hr play time per day) to a warm welcoming tone, and any initial harshness should disappear. Customers have reported a second break-in transition at about 100-125 hours during which the sound opens up tremendously to its final performance level

What about jitter? Does it matter for the dAck!?

Jitter is clock timing error that occurs during the transmission of the digital signal from the digital source to the DAC. While its existence has been known for years, its effects in audio are not well understood. What is known is that the frequency signature of jitter can dramatically affect the soundstage coherency and complex transient performance of a D-to-A converter. The dAck! has built-in defenses against jitter, but no device can completely remove it; jitter can only be attenuated, not removed. The dAck!’s performance scales directly with quality of the datastream it is fed, so it is worthwhile to get the best quality transport one can afford.

Robert Harley has published several excellent articles on the subject. These articles are available for free download on Stereophile’s website:
The Jitter Game
A Transport of Delight: CD Transport Jitter

Will you offer a Toslink or glass input option?

No. For consumer audio we believe that optical interconnection has more drawbacks than advantages. Its major advantage is noise isolation and low attenuation over long distances. The coaxial input is more robust and less sensitive to vibration. It does not age like optical since it is not sensitive to dust, and does not require messy optical coupling fluids for best performance. Additionally, coax is more amenable to the way audio connoisseurs tend to use equipment; switching cabling is more reliable and the signal paths are short enough that the length advantage of Toslink is moot. The dAck! is galvanically isolated from the source so there is no possibility of ground loops or hum.

For those with Toslink-only sources we can recommend the use of the Monarchy DIP classic or a simple Toslink-to-RCA converter. There are several on the market, please inquire for suggested products.

How long can I expect my batteries to last?

This is difficult to answer specifically. With the recommended usage cycle of up to 8 hours of listening before every recharge, you will get between 750 and 1000 charge/discharge cycles from your cells before they suffer diminished performance (this may or may not be noticeable). What this translates into in terms of years depends on your usage habits. If you use your dAck! 3-6 hours a day (one to two charge cycles), you can expect to replace the cells after about 1.5 to 2 years.

While the cells can readily be used in 6 to 8-hour cycles, we recommend usage in 4 hour increments for two reasons. First, 4 hours is a very shallow discharge cycle, which results in greatest battery longevity. Secondly (and perhaps more importantly), a 4-hour cycle encourages more consistent charge habits. This prevents the worst case scenario of leaving your dAck! on overnight one too many times, destroying the batteries.

You can tell if the battery should be replaced when you notice the sound gets much less sweet after a few hours of playback or, in the extreme case, a high pitched whine or static manifests after a few hours of use, and recharging the cells eliminates these effects.

Where do I get replacement batteries / Can I buy replacement batteries off the shelf?

The dAck! supply is in the form of a quick-release battery pack available from Ack! Industries. Because the packs have some protection circuitry built in and incorporate quick-release wiring, we do not recommend that you try to source batteries yourself.

 

 

Copyright and Trademark Notices Copyright (c) Ack! Industries and/or its licensors, 2005, all rights reserved. The Ack! logo is a registered trademark of Ack! Industries.