Review and Measurements of Benchmark DAC3

[Jimmy]

This is probably coil whine coming from the power supply at certain loads, which is common with switching mode PSUs.

It can often be fixed by identifying the component (normally an inductor) and covering with hot glue.

However, you will surely void your warranty, so I would suggest to use a power strip with a master switch, when you don't use it just turn it off. If you are willing to spend some extra money there are network managed power strips that can be controlled from a smartphone, just search for "smart power strip", for example :

https://www.amazon.com/Protector-Appliances-Individual-Schedule-Required/dp/B076VRH9WP

I’m a happy owner of a DAC3 HGC with the exception of one thing that really bothers me. When the device is powered off, but still plugged in to an outlet, it emits a faint high pitched squeal that is somewhat jarring in a quiet setting (or maybe I just have sensitive ears). I have it in my bedroom, and I find myself either physically unplugging it or leaving it powered on overnight so that it doesn’t disturb my sleep. Benchmark sent a replacement when I raised the issue a few weeks ago, but the second unit is now also exhibiting the same behavior. Are there any other owners of the DAC3 who are experiencing the same issue?

 

[cbnbmore]

Does the switch you have the DAC plugged into perhaps have a dimmer circuit or fan control connected to it?
Just for curiosity connect the DAC to another outlet in another room and see if it makes the same noise. If it doesn’t then you know there is an issue with the power at that outlet or in the room.

 

[ice]

No, there’s not really anything else connected that I can think of — the issue persists when I move it to another room. I think I’ll just go with switching off the power strip. Thanks everyone for the suggestions!

 

[Music1969]

Hi @John_Siau

I've read your technical note on why your DACs up-sample to PCM211kHz (input is limited PCM192kHz). Below for anyone interested.

Is there any reason why you don't instead up-sample to PCM422kHz or PCM844kHz? And maybe allow higher sample rates (up to DXD?)?

I know measurements are already state of the art , so it's more of a theoretical question (kind of), if there is advantage (or not) going to 422 kHz or 844 kHz..


"It is important to note that the DAC2 and DAC3 converters frequency-shift the selected built-in filter by driving the converter chip at a fixed 211 kHz sample rate. This frequency shifting places the near-Nyquist region entirely above the audio band. The Benchmark upsampling system completely eliminates the time-domain errors that would have been produced by the built-in filter. The 211 kHz upsampling frequency sets the cutoff frequency of the internal filter at 105 kHz. This places the filter transition region safely above the 96 kHz Nyquist frequency of a 192 kHz input sample rate. This unique Benchmark system prevents the near-Nyquist errors that would normally be produced by the filters in the D/A converter chip. This unique 211 kHz upsampling system allows us to implement a filter that is optimized for minimum passband ripple instead of using the default filter in the ES9028PRO.

The DAC3 and DAC2 both use the Benchmark 211 kHz upsampling system, and both provide outstanding frequency-domain and time-domain performance. But, due to the improvements in the ES9028PRO, the DAC3 has slightly less passband ripple than the DAC2."

 

[Veri]

Hi @John_Siau

I've read your technical note on why your DACs up-sample to PCM211kHz (input is limited PCM192kHz). Below for anyone interested.
Is there any reason why you don't instead up-sample to PCM422kHz or PCM844kHz? And maybe allow higher sample rates (up to DXD?)?

I reckon it's got to do with the clocks they use to have the best/nearest multiples of said clocks. I'm sure they tested and went with what got best results
Here's another, expensive studio DAC that upsamples to 211Khz btw http://www.cranesong.com/SOLARIS.html

 

[Music1969]

I'm sure they tested and went with what got best results

Yes that's already hinted in my post "I know measurements are already state of the art" .

But the question was direct to John so let's see from the expert ;-)

Asking out of general technical interest - not a 'deal breaker' question...

Multiples is also why I asked about 422 kHz and 844 kHz.... x2 and x4....

 

[tensor9]

Hi @John_Siau

I've read your technical note on why your DACs up-sample to PCM211kHz (input is limited PCM192kHz). Below for anyone interested.

Is there any reason why you don't instead up-sample to PCM422kHz or PCM844kHz? And maybe allow higher sample rates (up to DXD?)?

I know measurements are already state of the art , so it's more of a theoretical question (kind of), if there is advantage (or not) going to 422 kHz or 844 kHz..


"It is important to note that the DAC2 and DAC3 converters frequency-shift the selected built-in filter by driving the converter chip at a fixed 211 kHz sample rate. This frequency shifting places the near-Nyquist region entirely above the audio band. The Benchmark upsampling system completely eliminates the time-domain errors that would have been produced by the built-in filter. The 211 kHz upsampling frequency sets the cutoff frequency of the internal filter at 105 kHz. This places the filter transition region safely above the 96 kHz Nyquist frequency of a 192 kHz input sample rate. This unique Benchmark system prevents the near-Nyquist errors that would normally be produced by the filters in the D/A converter chip. This unique 211 kHz upsampling system allows us to implement a filter that is optimized for minimum passband ripple instead of using the default filter in the ES9028PRO.

The DAC3 and DAC2 both use the Benchmark 211 kHz upsampling system, and both provide outstanding frequency-domain and time-domain performance. But, due to the improvements in the ES9028PRO, the DAC3 has slightly less passband ripple than the DAC2."

I’m really curious as to why they don’t upsample to 2112 kHz (2.11 MHz), the least common multiple of 44, 88, 96, 176, and 192. Interesting that 211 kHz is exactly a tenth of this least common multiple. Sort of like Ted Smith does when he upsamples everything to 20x DSD for processing in the Directstream DAC.

 

[ayane]

I’m really curious as to why they don’t upsample to 2112 kHz (2.11 MHz), the least common multiple of 44, 88, 96, 176, and 192. Interesting that 211 kHz is exactly a tenth of this least common multiple. Sort of like Ted Smith does when he upsamples everything to 20x DSD for processing in the Directstream DAC.

The LCM of 44.1 kHz and 48 kHz is 7.056 MHz, not 2.112 MHz.

I don't believe there's any particular reason for 211 kHz; I think it's just an arbitrary number chosen based on the processing power capabilities of the DSP in the DAC3, maybe clock performance as well, unless @John_Siau would like to chime in.

Edit: Speaking of filters, @amirm have you posted a measurement of the white noise response for the DAC3? I'm really curious to see its passband considering the engineering behind its DSP!

 

[tensor9]

The LCM of 44.1 kHz and 48 kHz is 7.056 MHz, not 2.112 MHz.

I don't believe there's any particular reason for 211 kHz; I think it's just an arbitrary number chosen based on the processing power capabilities of the DSP in the DAC3, maybe clock performance as well, unless @John_Siau would like to chime in.

Edit: Speaking of filters, @amirm have you posted a measurement of the white noise response for the DAC3? I'm really curious to see its passband considering the engineering behind its DSP!

I didn’t say 2.112 MHz was a LCM of 44.1 and 48, I said it was of 44 and 48. I realize 44 is not the exact sampling rate, but the 211 number is probably not an accident.

 

[Shangri-La]

Wonder if/when the DAC3 replacement is coming out. As great as it sounded in my system, I'm a bit hesitant buying a 3-year old product, as DAC is what benefits the most from new technologies.

As for equipment break-in, I wasn't a beliver before either but it made a clear difference in the DAC3. After 200 hours of break-in, the DAC3 CLEARLY sounded better. Speakers are GoldenEar Triton Reference. It may not need that much time but that's what was needed for PS Audio M700, which also sounded better. You dont have to believe or disbelieve break-in, your ears will tell you it is a fact. At lease in case of DAC3 and M700.

 

[Sal1950]

You dont have to believe or disbelieve break-in, your ears will tell you it is a fact. At lease in case of DAC3 and M700.

Would you please supply us with some verifiable evidence of this?
Your eyes will tell you David Copperfield made a 747 disappear off the runway..
But of course it really didn't, it was simply an illusion.

 

[Shangri-La]

Would you please supply us with some verifiable evidence of this?
Your eyes will tell you David Copperfield made a 747 disappear off the runway..
But of course it really didn't, it was simply an illusion.

Play any song through your smart phone speaker. Play the same song with your smart phone connected to a pair of Elac bookshelf speaker.

Which sounds better, what's the verifiable evidence?

 

[Sal1950]

Which sounds better, what's the verifiable evidence?

Easily measurable.
Where's yours?

 

[Shangri-La]

Easily measurable.
Where's yours?

But do you need to measure to believe there's a difference?

What have you tried to not believe burn-in? Measurements?

 

[THW]

But do you need to measure to believe there's a difference?

What have you tried to not believe burn-in? Measurements?

it could easily be a matter of the time of the day that you listened to the equipment, humans tend to hear better during certain timings. i've had this experience myself, however you're free to take it with a grain of salt since it wasn't a direct A/B comparison.

to jump the gun and conclude that something sounds better because of burn-in is ridiculous when you have yet to consider other possible known factors.

 

[Shangri-La]

So, I've tried in a non-scientific way that leads me to believe burn-in makes a difference.

What scientific tests have you guys done to prove burn-in makes no difference?

 

[Thomas savage]

The more likely variable is the human being , it's interesting that people tend not to consider this as even being remotely possible.

Let's not get caught up in this old debate.

 

[Sal1950]

So, I've tried in a non-scientific way that leads me to believe burn-in makes a difference.

What scientific tests have you guys done to prove burn-in makes no difference?

That's what we do here, provide evidence to claims that are made.
Now the balls in your court to provide the evidence.

Many products get measured many times over, if changes occur, some component is failing.

 

[Shangri-La]

That's what we do here, provide evidence to claims that are made.
Now the balls in your court to provide the evidence.

Many products get measured many times over, if changes occur, some component is failing.

What have you tried at all, scientific or non-scientific, on the subject of burn-in?

 

[Shangri-La]

Here's how I tried.

Before burn-in, the DAC3 was hardly better than my old dac.

After burn-in, the DAC3 was clearly better. Any time I A/B, the difference is obvious.

What have you done?