Benchmark DAC1 now available with USB

[Lord Chaos]

Add me to the list of folks who'd like to have a DAC1 Firewire.

 

[EliasGwinn]

Quote:

Originally Posted by hh83917 /img/forum/go_quote.gif Remote (not the prettiest but gets the job done)

The remote was selected for its simplicity, long range, and resistance to interference from other remotes. We developed our own hardware IR decoder to eliminate the need to place a noisy microprocessor in the DAC1 chassis. The exceptional timing accuracy of our hardware IR decoder gives the DAC1 HDR exceptional immunity to false triggers caused by other IR remotes, Video sceens, and high-efficiency flourescent lighting. A metal remote would have added significant costs without improving audio quality. We invested money in the audio path (custom Alps pot) rather than on the remote control housing. Other manufacturers have implemented cheap IC-based analog or digital volume controls but increase price because of a fancy remote.

We expect many of our users will control the DAC1 HDR from a universal remote such as one from the Logitch Harmony series. Harmony files supporting the HDR will be available soon. Until then, the Harmony remotes can learn the HDR command set.

All the best,
Elias

 

[hh83917]

Quote:

Originally Posted by EliasGwinn /img/forum/go_quote.gif The remote was selected for its simplicity, long range, and resistance to interference from other remotes. We developed our own hardware IR decoder to eliminate the need to place a noisy microprocessor in the DAC1 chassis. The exceptional timing accuracy of our hardware IR decoder...etc.

Elias,

Don't worry, I wasn't complaining. I like the remote a lot and its key placements. Frankly, I quite enjoy the simplicity of it. The remote works very well with the IR decoder in the HDR and, thanks to Benchmark's hard work, is extremely responsive to the remote. I only wonder if its durability will match the DAC1. But, if I can always order a replacement if it ever break or get lost, I don't see a problem with it.

I currently use the HDR mainly on my iMac, but talking about the Harmony remotes, I do own two of them, the old 880 and the newer Harmony One. I use the Harmony One on my home theater system, but although it drops the learning curve and complexities for the rest of the family, I found it to be a bit laggy and unresponsive even after tweaking (personal opinion). The relationship is something like: "I like it, but it can be much better...", but I guess that's Logitech's problem. Anyways, it is nice to see Benchmark submitting the remote codes to the Harmony database. It will make many home theater enthusiasts very happy.

Best regards,
Howard.

 

[G-U-E-S-T]

Hi Elias,

Naive question please: With the new remote-motorized volume control, is it better to always use the remote for volume adjustment, instead of turning the volume control manually? I.E. Is it now discouraged (or perhaps risky to the operation of the motorized pot etc), to make a habit of just adjusting the volume control by hand?

 

[little-endian]

Hi Elias,

after quite a while, I'd have two questions about the DAC1's volume control, important for me in particular at present:

After having not used the DAC1 (the classic version) for about a month, I encountered slight crackling noises when adjusting the volume. Since it is for the time of adjustment only, it is definitely due to the poti, what makes be wonder if that's such a good sign. It disappears again after some movements and otherwise, the DAC1 is in best shape, though.

Benchmarks claims that their decision to use a poti instead of an electronic volume control would be that the last one wouldn't archive the same quality - also in terms of dynamic range.

However, that seems somehow odd to me. Aren't there nowadays suitable DSPs, able to handle 32-bit or more floating point precision to control the volume by math? If it is not implemented correctly, one would get a higher noise floor of course but is there really no way for Benchmark to implement this? Somehow, this analog poti seems like the only real "weak point" of the DAC1 since prone to wear...

 

[EliasGwinn]

Quote:

Originally Posted by G-U-E-S-T /img/forum/go_quote.gif Hi Elias, Naive question please: With the new remote-motorized volume control, is it better to always use the remote for volume adjustment, instead of turning the volume control manually? I.E. Is it now discouraged (or perhaps risky to the operation of the motorized pot etc), to make a habit of just adjusting the volume control by hand?

Not at all. The motor is built with a clutch so that manual adjustments (including overriding the motor while it is being driven) will not fatigue the motor or potentiometer.

Feel free to adjust the volume by hand or remote or both (even at the same time!).

All the best,
Elias

 

[EliasGwinn]

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif Hi Elias, after quite a while, I'd have two questions about the DAC1's volume control, important for me in particular at present: After having not used the DAC1 (the classic version) for about a month, I encountered slight crackling noises when adjusting the volume. Since it is for the time of adjustment only, it is definitely due to the poti, what makes be wonder if that's such a good sign. It disappears again after some movements and otherwise, the DAC1 is in best shape, though. Benchmarks claims that their decision to use a poti instead of an electronic volume control would be that the last one wouldn't archive the same quality - also in terms of dynamic range. However, that seems somehow odd to me. Aren't there nowadays suitable DSPs, able to handle 32-bit or more floating point precision to control the volume by math? If it is not implemented correctly, one would get a higher noise floor of course but is there really no way for Benchmark to implement this? Somehow, this analog poti seems like the only real "weak point" of the DAC1 since prone to wear...

We can replace your potentiometer. Call us to set up an RMA (1-800-BNCHMRK / 1-800-262-4675).

The DAC1 HDR's potentiometer is much higher quality, and is less prone to this issue.

With regards to a DSP volume control, digital attenuation will always reduce the dynamic range of a converter, no matter how well it is built. I'm actually writing an article for our Feedback Newsletter outlining the various volume control mechanisms.

All the best,
Elias

 

[ert]

Speaking of knobs, the source knob on my DAC1 PRE is loose. Is there a way to tighten the knob on the shaft? Sometimes there's a set screw, but I can't see one.

 

[little-endian]

Hi Elias,

thanks for the quick reply, also if it is not what I wanted to hear.

Hmm, so I interprete that as a "not so good sign". What causes that behavour actually? Why does it disappear again after a while of usage? Seems like a contact issue. Besides the slight noise occuring during the adjustment, are there any other degrades in sound quality to expect (in theory)?

I called the number you had given, however I seem to have missed office hours for today already.

Some more questions in advance:

1. If I do nothing, will it get worse or remain more or less the same?

2. I purchased the device 2007 from the official seller in Germany at that time, Analog Audio. How would such a RMA take place in detail? What about shipping / customs fuss?

3. If I decide to get it replaced, would it be possible to get such a potentiometer used for the DAC1 HDR or even replace the whole DAC1 to a HDR (paying the difference)?

I'm keen on reading your article about volume controls since I'm still confused why volume controls, offered by some software like iTunes and others are said to have gained quite a nice performance meanwhile while implementing this into a DAC shall still be that big problem.

 

[EliasGwinn]

Quote:

Originally Posted by ert /img/forum/go_quote.gif Speaking of knobs, the source knob on my DAC1 PRE is loose. Is there a way to tighten the knob on the shaft? Sometimes there's a set screw, but I can't see one.

The source knob is a friction fit...i.e, there is no set screw. I've never seen one come loose. Hmmm...???

We can replace the knob and/or source switch for you. Call us (9a-5p EST)to set up an RMA (1-800-BNCHMRK / 1-800-262-4675).

All the best,
Elias

 

[EliasGwinn]

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif Hmm, so I interprete that as a "not so good sign". What causes that behavour actually? Why does it disappear again after a while of usage? Seems like a contact issue. Besides the slight noise occuring during the adjustment, are there any other degrades in sound quality to expect (in theory)? 1. If I do nothing, will it get worse or remain more or less the same? 2. I purchased the device 2007 from the official seller in Germany at that time, Analog Audio. How would such a RMA take place in detail? What about shipping / customs fuss? 3. If I decide to get it replaced, would it be possible to get such a potentiometer used for the DAC1 HDR or even replace the whole DAC1 to a HDR (paying the difference)? I'm keen on reading your article about volume controls since I'm still confused why volume controls, offered by some software like iTunes and others are said to have gained quite a nice performance meanwhile while implementing this into a DAC shall still be that big problem.

Contact Analog Audio to have your DAC1 PRE repaired. They are an authorized repair station for us.

The pot noise doesn't affect the overall performance of the DAC1 PRE, it simply makes a noise during rotation. It is an easy repair, and if your warranty is valid, it will be covered.

Regarding upgrading, the DAC1 PRE cannot be retro-fitted with the new custom Alps pot. Ask Analog Audio about their policies for trade-ins, but I think that they do not allow it.

DSP volume controls, such as that in iTunes or one built into a DAC, can perform wonderfully. However, ALL pre-DAC digital attenuation will lower the dynamic range. In other words, they will reduce the signal-to-noise ratio. Here's why:

Imagine a room with 10 foot ceilngs. In this example, the 'ceiling' is the 'maximum output' from the converter. The 'floor' is the 'noise floor' of the converter. The 'height' of the room is the 'dynamic range'. The noise floor of the converter is constant, regardless of the level of the input signal. If the ceiling (volume) is too high, you can install a suspended ceiling (digitally attenuate the volume). However, the floor will remain at the same level. By using digital attenuation, the ceiling is lowered, but the 'noise floor' stays the same. Therefore, you have less height (dynamic range).

With post-DAC attenuation, you attenuate everything coming from the DAC: the signal (ceiling) AND the noise (floor). Therefore, the height (dynamic range) remains the same (assuming you are using an attenuator that doesn't contribute too much noise).

Does that make sense?

Thanks,
Elias

 

[little-endian]

Hello Elias,

thanks again.

Well, actually it is the "old" DAC1 without USB - the one Allen Burdick owned before to be exact.

Hmm, right now the slight noise is gone. It is not really an issue (right now), more a psychological one (a weak point of the 'perfect' DAC1 since other parts like the chipset have no wear at all, right?)

Actually, that topic deserves an own thread in my opinion but I'll risk it to post it here:

Yeah, nice example. However, maybe you forgot to mention the floor's basement below.

Feel free to correct me if I should be wrong; the following according to my current knowledge:

1. Dynamic range and signal to noise ratio are not exactly the same, although normally used synonymously, right? At least, the "mastering guru" Bob Katz explained that with usage of dithering, one may archive a higher dynamic range than the SNR (for 16 bit a DR of about 120 dB and SNR of 91 dB for instance). It seems that information can be retrieved even at negative SNRs, where the noise is louder than the actual signal.

2. In the case of the DAC1, the SNR is about ~ 116 dB according to the data sheet. No word about the dynamic range, though. As far as remember, how already stated somewhere here that the DAC1 would be able to perform at true 24-bit accuracy, however would be limited in terms of SNR by its own noise @ -116dBFS.

3. If we adjust the volume before converting it to analog, there are two causes of quality degradation in theory: Due to the performed math and rounding errors and the fact that the maximum values reached by the audio signal would be always lower than 0dBFS, reducing the dynamic range by definition - right?

So I understand your point, however I have a "crucial question" as a 'counterstrike':

Of course, our ear's dynamic range (and signal to noise ratio as well I think) is limited also of course. So when using a poti (assuming it won't introduce any noise by its own), the signal as well as the noise would be lowered the same, keeping the dynamic range the same by definition (DR = max / min). Assuming some music that reaches 90 dB in its loudest parts at a given playback volume and calm periods at 20 dB. Now I lower the volume with your poti. In theory, the dynamic range stays the same, right? But now the loudest parts may not louder than 60 dB for instance. What happens with the low parts then? Aren't they lost anyway because they would below 0dBSPL? As far as I know, the maximum hearable dynamic range is limited by the playback volume as well - if one wants to hear something on a lower volume (than intended), one has to choose wether to lose the lower parts or to compress the dynamic range (like Dolby's midnight modes offer it).

So far my confusion.

 

[EliasGwinn]

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif 1. Dynamic range and signal to noise ratio are not exactly the same, although normally used synonymously, right? At least, the "mastering guru" Bob Katz explained that with usage of dithering, one may archive a higher dynamic range than the SNR (for 16 bit a DR of about 120 dB and SNR of 91 dB for instance). It seems that information can be retrieved even at negative SNRs, where the noise is louder than the actual signal.

Yes and no...there are a lot of conflicting opinions on this. Dynamic range (DR) and signal-to-noise ratio (SNR) spec's are effectively telling the same story for an audio component. However, they are often calculated and stated differently.

Here's the story behind DR and SNR measurements of digital audio gear: SNR is calculated by measuring the output level of a device with a known input signal, then measuring the noise floor with no input signal. The difference between those measurements (the max output and noise floor) is the SNR.

However, many manufacturers of DAC's, CD players, etc, install auto-mute circuits to mute the DAC's output when there was no digital audio input. This caused false SNR measurements because the noise measurements were artificially low. DR measurements were introduced to defeat this. DR is calculated by measureing the noise floor while sending a very low input signal (-60 dBFS) into the device. This low-level signal prevents the auto-mute circuit from engaging. (An example of a suspicious SNR spec is the Bryston BDA-1, which uses the Cirrus CS4398 DAC chip. The Cirrus chip has a dynamic range of 120 dB. However, the Bryston BDA-1 claims to have a "signal-to-noise ratio of -140 dB". Even if they paralelled 8 of the Cirrus chips, they couldn't reduce the noise level 20 dB. The Bryston needs to be tested with a low-level signal to determine the dynamic range without muting.)



http://www.cirrus.com/en/pubs/proDat.../CS4398_F1.pdf

To answer your other question... it is true that a properly-dithered digital recording can capture details well below the noise floor. It is also true that human's can hear sounds below the noise floor. There have been many demonstrations of this.

Dynamic range, as Bob Katz was referring to it, can also describe the difference between the highest and lowest levels of sound. For example, the dynamic range of a recording describes the difference between the loudest passages and the quietest passages. In this case, dynamic range has nothing to do with the noise floor (unless the quietest passage is REALLY quiet).

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif 2. In the case of the DAC1, the SNR is about ~ 116 dB according to the data sheet. No word about the dynamic range, though. As far as remember, how already stated somewhere here that the DAC1 would be able to perform at true 24-bit accuracy, however would be limited in terms of SNR by its own noise @ -116dBFS.

Correct. Specifically, the intrinsic noise of the D/A chip is the dominating noise contributor. This is the case with most DAC's (although some don't like to admit it...see comments above)

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif 3. If we adjust the volume before converting it to analog, there are two causes of quality degradation in theory: Due to the performed math and rounding errors and the fact that the maximum values reached by the audio signal would be always lower than 0dBFS, reducing the dynamic range by definition - right?

A properly dithered, high-quality digital volume control won't degrade the signal. It will simply lower the dynamic range of the DAC. If the digital audio is dithered to 16-bits (as in the case with 16-bit USB devices), it will also increase the noise level of the recording.

Quote:

Originally Posted by little-endian /img/forum/go_quote.gif Of course, our ear's dynamic range (and signal to noise ratio as well I think) is limited also of course. So when using a poti (assuming it won't introduce any noise by its own), the signal as well as the noise would be lowered the same, keeping the dynamic range the same by definition (DR = max / min). Assuming some music that reaches 90 dB in its loudest parts at a given playback volume and calm periods at 20 dB. Now I lower the volume with your poti. In theory, the dynamic range stays the same, right? But now the loudest parts may not louder than 60 dB for instance. What happens with the low parts then? Aren't they lost anyway because they would below 0dBSPL? As far as I know, the maximum hearable dynamic range is limited by the playback volume as well - if one wants to hear something on a lower volume (than intended), one has to choose wether to lose the lower parts or to compress the dynamic range (like Dolby's midnight modes offer it).

Not really. Supposedly the dynamic range of human hearing is near 100 dB. Recorded music rarely has 40 dB of dynamic range, let alone 70 dB as in your example.

Most importantly, your example outlines the reason for proper gain staging. If your amplifier is the correct size (maximum output is barely louder then the loudest you would ever listen) and gain stages of your devices are properly configured (keeping signals as hot as possible between devices and attenuate for volume control only near the end of the signal path), the dynamic range will be maintained. In other words, full-digital amplitude into the DAC1 -> analog volume control -> proper-size amplifier -> speakers.

All the best,
Elias

 

[geremy]

Has anyone compared the DAC1 USB or PRE with the Lavry DA10 or DA11? I am having a hard time deciding between these two units. I appreciate Benchmark's openness concerning the design and performance of their unit. Lavry does not operate in the same manner, so it is hard to make direct comparisons.

I have found plenty of reviews pitting the DAC1 vs. the DA10, but this was before Benchmark upgraded the op-amps in the analog path.

Thanks.

 

[aCuria]

Quote:

Originally Posted by geremy /img/forum/go_quote.gif Has anyone compared the DAC1 USB or PRE with the Lavry DA10 or DA11? I am having a hard time deciding between these two units. I appreciate Benchmark's openness concerning the design and performance of their unit. Lavry does not operate in the same manner, so it is hard to make direct comparisons. I have found plenty of reviews pitting the DAC1 vs. the DA10, but this was before Benchmark upgraded the op-amps in the analog path. Thanks.

Theres a thread here.
http://www.head-fi.org/forums/f7/ben...6/#post5686982

The USB and PRE are relatively new and there are few direct comparisons.