Inside the latest Benchmark DAC1

[Iron_Dreamer]

Quote:

Originally Posted by Ferbose I am sorry for sounding ignorant... How much is this Gilmore amp and where may I find information about it on the web? Thanks.

Well, I'm referring to the classic Gilmore V1, which originally sold for $500 (I think), built by headamp.com. I don't know of any page with specific information about this model, but they have the run-down on the current ones they produce. It is based on Dr. Kevin Gilmore' discrete dynamic headphone amp design, which you can find more about on headwize.

 

[raif]

Quote:

Originally Posted by ayt999 I think raif needs to come over again with his benchmark so we can test it out again.

I'm in.
We have to do it before you get any more equipment though, it is getting harder and harder to leave each time.

 

[Iron_Dreamer]

Ed, once I hooked up my glass toslink and Quail PC, any notion of light bass went bye-bye, which is not to say the bass is bloated either, I find it very accurate (as far as the source goes) now. It is wimpy on thin recordings, but powerful on great ones, and as low as ever.

I am starting to think, as great as things sound, that it is a bit too bright with the CD3000. Aye, aye, aye, where do I go from here!

 

[Edwood]

Quote:

Originally Posted by Iron_Dreamer Ed, once I hooked up my glass toslink and Quail PC, any notion of light bass went bye-bye, which is not to say the bass is bloated either, I find it very accurate (as far as the source goes) now. It is wimpy on thin recordings, but powerful on great ones, and as low as ever. I am starting to think, as great as things sound, that it is a bit too bright with the CD3000. Aye, aye, aye, where do I go from here!

Hmmm, I guess power is more critical for DAC's. I wonder how it'll sound supplied with power from a P300?

How does the Benchmark sound feeding your Gilmore?

CD3000 too bright? Hmmm, get an R10 next?

Well, I'm interested with how it sounds with the Grace as well.

-Ed

 

[Iron_Dreamer]

Quote:

Originally Posted by Edwood Hmmm, I guess power is more critical for DAC's. I wonder how it'll sound supplied with power from a P300? How does the Benchmark sound feeding your Gilmore? CD3000 too bright? Hmmm, get an R10 next? Well, I'm interested with how it sounds with the Grace as well. -Ed

Sound is about the same using the Gilmore, it adds a little bass but sacrifices some of the instant-on/off dynamics or speed. I guess the P300 would only make it better, if I could imagine that. Believe it or not, I think the best part of the sound is the mids, just so nice and fluid without being overly warm. I wish it was an R10 next, perhaps it will be HD650 with silver cables.

 

[Iron_Dreamer]

Ed, I'm comparing the DAC1 to a bypass modded RME I just did for another head-fier, and I think you're going to like my new source, a LOT. It is a definite order-of-magnitude improvement overall (several if you already considered the HDSP one), and the bass is definitely more powerful. Not louder, but just tighter, punchier, with more oooomph in the same notes. Whether it is enough for the R10's is up to the amp, I can definitely say as a source, the job is done by producing great bass. To me the modded PAD sounds quite slow and boring compared to the DAC1.

 

[Jasper994]

Quote:

Originally Posted by Iron_Dreamer Ed, I'm comparing the DAC1 to a bypass modded RME I just did for another head-fier, and I think you're going to like my new source, a LOT. It is a definite order-of-magnitude improvement overall (several if you already considered the HDSP one), and the bass is definitely more powerful. Not louder, but just tighter, punchier, with more oooomph in the same notes. Whether it is enough for the R10's is up to the amp, I can definitely say as a source, the job is done by producing great bass. To me the modded PAD sounds quite slow and boring compared to the DAC1.

You know I'm going to laugh my ***** off if you end up with HD650's...

 

[Iron_Dreamer]

Quote:

Originally Posted by Jasper994 You know I'm going to laugh my ***** off if you end up with HD650's...

I know, I know, but that is just the way things go. At least I don't lose money every time I change cans

 

[jsiau]

Quote:

Originally Posted by Glassman I bet it's all thanks to a clean clock produced onboard.. you can even substitute AD1896A with SRC4192 by Burr Brown, even better specs..

The Burr Brown part has better THD and SNR specs, but it has almost no jitter immunity. The corner frequency of the digital PLL is set way too high on the Burr Brown part. This is an unfortunate defect in an otherwise outstanding part. The SCR4192 will defeat all of the jitter immunity in the DAC1. I do not recommend substituting the Burr Brown part into a DAC1 in any application.

John Siau
Director of Engineering
Benchmark Media Systems, Inc.
www.benchmarkmedia.com

 

[jsiau]

Quote:

Originally Posted by Iron_Dreamer I can see how you'd find other DAC's more musical, this one is intended to be as clean and neutal as possible, it even says so in the manual, part of their philosophy is that the DAC and ADC stages of any rig should be neutral, since their color would show up in all future sounds produced by said rig.

Exactly!

We designed the DAC1 for maximum transparency. If you want to add warmth, you can't add it with a DAC1. Personally, I do not like what warm sounding equipment does to the sound of a piano. Warmth is wonderful on vocals, guitars and certain instruments, but it beats against the streched overtones of a piano. The overtones in a piano occur at slightly higher than harmonic ratios, and these create beat notes with the exact integer ratios produced by electronic equipment (and speakers). Too much harmonic distortion will make a piano sound out of tune.

Put on a pair of HD600 headpones, plug them in to the DAC1 headphone amp, and listen to a solo piano recording. This combination will deliver far lower distortion than any speaker/amplifier combination. The 0-Ohm headphone drive on the DAC1 is extreemly clean under load.

John Siau
Director of Engineering
Benchmark Media Systems, Inc.
www.benchmarkmedia.com

 

[Iron_Dreamer]

Quote:

Originally Posted by jsiau The Burr Brown part has better THD and SNR specs, but it has almost no jitter immunity. The corner frequency of the digital PLL is set way too high on the Burr Brown part. This is an unfortunate defect in an otherwise outstanding part. The SCR4192 will defeat all of the jitter immunity in the DAC1. I do not recommend substituting the Burr Brown part into a DAC1 in any application. John Siau Director of Engineering Benchmark Media Systems, Inc. www.benchmarkmedia.com

Thanks for the input. I sure as hell wasn't going to make that swap, after looking at the data sheets. Good to know we've managed to attract your ear around here

 

[ampgalore]

Wow, representative from Benchmark is here

While you are here, any scoops on future upgrades to the DAC1?

And what's your opinion on Bel Canto DAC2? How does that compare to the Benchmark?

 

[Wodgy]

Quote:

Originally Posted by jsiau The Burr Brown part has better THD and SNR specs, but it has almost no jitter immunity. The corner frequency of the digital PLL is set way too high on the Burr Brown part. This is an unfortunate defect in an otherwise outstanding part. The SCR4192 will defeat all of the jitter immunity in the DAC1. I do not recommend substituting the Burr Brown part into a DAC1 in any application.[/url]

Jsiau, this is very interesting. Do you have any evidence to back this up? e.g. measurements, info from the datasheet, that kind of thing? The datasheet claims just the opposite, but does not seem to provide measurements. However, it would seem that Burr Brown would be incurring nontrivial legal risk (misrepresentation) by claiming something that wasn't the case. Are you sure your SRC4192 implementation was done correctly?

Frankly, the SRC4192 represents a very substantial engineering effort and I would be very surprised if the kind of defect you're claiming exists and made it through to production.

 

[jsiau]

Quote:

Originally Posted by Iron_Dreamer Coming from someone who designs and sells (very nice IMO) DAC's, I think this statement could not be emphasized more. This DAC sounds damn amazing, and could probably sell for several times its price, for the sound it delivers. Although I wonder if better opamps would improve it, I don't want to fiddle with this thing, and I don't think that'll change in a few weeks

Don't underestimate the NE5532. We have just completed a very comprehensive set of tests on the NE5532 and on various substitutes. We have not found anything that will equal the tranparency provided by the NE5532.

Some have suggested susbstituting OPA2134 op amps in place of the 5532s. This is a bad idea! Our tests show an increase in both 2nd and 3rd harmonic distortion, and the addition of higher order (4th, 5th, 6th, and 7th) harmonics that are virtually absent from a stock DAC1. In addition, IMD will increase, and SNR will degrade.

The NE5532 is power hungry, it has high input bias currents, and high offset voltage, but it can drive high-level low impedance circuits with ease. The 5532 should not be used with low signal levels, and it should only be used in low gain circuits. Also, the offset voltage must be managed with appropriate design techniques. I believe the NE5532 has aquired a bad reputation because it has often been missapplied. The DAC1 is carefully designed specifically for the NE5532 op amp. It may surprise you that the NE5532 was selected for transparency and not on the basis of cost.

John Siau
Director of Engineering
Benchmark Media Systems, Inc.
www.benchmarkmedia.com

 

[jsiau]

Quote:

Originally Posted by Wodgy Jsiau, this is very interesting. Do you have any evidence to back this up? e.g. measurements, info from the datasheet, that kind of thing? The datasheet claims just the opposite, but does not seem to provide measurements. However, it would seem that Burr Brown would be incurring nontrivial legal risk (misrepresentation) by claiming something that wasn't the case. Are you sure your SRC4192 implementation was done correctly? Frankly, the SRC4192 represents a very substantial engineering effort and I would be very surprised if the kind of defect you're claiming exists and made it through to production.

They are aware of the problem. It will get fixed.