Benchmark DAC1 now available with USB

[EliasGwinn]

Originally Posted by Scrith

Quick question about the new DAC1 USB:

Other than the USB support, is there anything new (or improved) about the DAC section of the DAC1?

I am a previous DAC1 owner (both a 2004 and an early 2006 model, which sounded different, by the way) that switched to another DAC that, in my opinion, sounded slightly better than the DAC1 (which I attributed to the resampling that was happening in the DAC1 in order to deal with jitter). I am using an external box to convert USB to S/PDIF (and wouldn't mind eliminating this USB box from the chain if I could replace my box+DAC with a new DAC1 USB and get sound that is at least as good).

By the way, I always found that resampling up to 96K using a high-quality resampler (such as the Secret Rabbit resampler in Foobar2000) improved the sound with the DAC1, which I also attributed to the (relatively) poor job the DAC1 was doing in resampling music from 44K all the way to 117K (a guess...I don't remember the exact value of the data rate the DAC1 uses internally). Has the hardware that is being used to resample the data to the internal rate changed at all?

The DAC1 USB has several new features as compared to the DAC1. These are:

* True native 24/96 bit-transparent USB audio interface
* High-current output drivers (read end of previous post about this)
* Two gain ranges for headphone amplifier for more/less sensitive headphones
* Main outputs mute on headphone insertion (this feature is defeatable)

Thanks,
Elias

[EliasGwinn]

Originally Posted by Audio_newb

Elias, thanks for answering all our questions so far both here and over at the stereophile forums. I was wondering whether, now that there is a usb connection we might see future firmware updates and whether you guys were still working on anything like that. Thanks.

Firmware updates will be addressed when it is apparent they are necessary. So far, the device seems to work flawlessly.

Thanks,
Elias

[EliasGwinn]

Originally Posted by Shout It Out Lou

Hey Elias, to get terribly unsimple for one second and ask a direct question - are there any plans to ever release a remote controllable Dac1? This is the only thing stopping me from buying one now (used to own one but missed being lazy!).

We currently have no plans to incorporate a remote control into the DAC1 design, but we appreciate the suggestion and will keep it in consideration.

Thanks,
Elias

[EliasGwinn]

Originally Posted by boggle

I have a question for Mr Gwinn. What do you (or others) think of the price doubling Empirical Audio Benchmark mod? I have read that the dac1 has 'empirically' (no pun intended) perfect specs - so where is the improvement?

If you are considering having your DAC1 modified, please read Benchmark's official statement regarding modifications to Benchmark products (copied directly from Benchmark DAC1 USB manual, page 2 - http://www.benchmarkmedia.com/manual...USB_Manual.pdf ):

Benchmark’s official statement regarding modifications:

"CAUTION: DO NOT SUBSTITUTE PARTS OR MAKE ANY MODIFICATIONS WITHOUT THE WRITTEN APPROVAL OF BENCHMARK MEDIA SYSTEMS, INC. MODIFICATION MAY CREATE SAFETY HAZARDS AND VOID THE WARRANTY.

NOTICE: CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY BENCHMARK MEDIA SYSTEMS COULD VOID THE USER'S AUTHORITY TO OPERATE THE EQUIPMENT UNDER FCC REGULATIONS."

John Siau, the director of engineering, and chief designer of the DAC1, has addressed this, so I will copy his response here.

John Siau: "I have not seen, measured, or listened to a modification that I would recommend. Modified units usually perform more poorly. We have measured modified units and have found the following problems:

a) Distortion due to opamp substitutions
b) Phase errors between channels due to capacitor changes
c) UltraLock(tm) rendered non-functional due to IC change
d) Frequency response problems due to substitution of incorrect capacitor values.

We have fixed several modified units at customer expense after they failed. This has given us the opportunity to measure the performance and inspect the workmanship. In all cases the performance was degraded. In all of these RMA cases, the modifications caused failure of the product. I do not recommend the services of modifiers. We had good reasons for using the parts that we used. Our reasons had everything to do with performance and nothing to do with cost.

OPA627 vs. NE5532:

The OPA627 will offer no advantage over the NE5532 in this application. High-frequency THD+N may actually be slightly higher with the OPA627. We are using the new LM4562A in the DAC1 USB. The LM4562A is pin-compatible with the NE5532, but you can't just drop it in and get all of the advantages of the DAC1 USB. We changed all of the resistors in the XLR output pads to take advantage of the high drive capability of the LM4562A."

Pay particular attention to items B and D in the list above. The modified units we have seen have incorrect capacitor values substituted for the original parts. Substituting incorrect capacitor values will result in serious deficiencies in sound field accuracy and also freq response accuracy.

Thanks,
Elias

[kool bubba ice]

Originally Posted by EliasGwinn

If you are considering having your DAC1 modified, please read Benchmark's official statement regarding modifications to Benchmark products (copied directly from Benchmark DAC1 USB manual, page 2 - http://www.benchmarkmedia.com/manual...USB_Manual.pdf ):

Benchmark’s official statement regarding modifications:

"CAUTION: DO NOT SUBSTITUTE PARTS OR MAKE ANY MODIFICATIONS WITHOUT THE WRITTEN APPROVAL OF BENCHMARK MEDIA SYSTEMS, INC. MODIFICATION MAY CREATE SAFETY HAZARDS AND VOID THE WARRANTY.

NOTICE: CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY BENCHMARK MEDIA SYSTEMS COULD VOID THE USER'S AUTHORITY TO OPERATE THE EQUIPMENT UNDER FCC REGULATIONS."

John Siau, the director of engineering, and chief designer of the DAC1, has addressed this, so I will copy his response here.

John Siau: "I have not seen, measured, or listened to a modification that I would recommend. Modified units usually perform more poorly. We have measured modified units and have found the following problems:

a) Distortion due to opamp substitutions
b) Phase errors between channels due to capacitor changes
c) UltraLock(tm) rendered non-functional due to IC change
d) Frequency response problems due to substitution of incorrect capacitor values.

We have fixed several modified units at customer expense after they failed. This has given us the opportunity to measure the performance and inspect the workmanship. In all cases the performance was degraded. In all of these RMA cases, the modifications caused failure of the product. I do not recommend the services of modifiers. We had good reasons for using the parts that we used. Our reasons had everything to do with performance and nothing to do with cost.

OPA627 vs. NE5532:

The OPA627 will offer no advantage over the NE5532 in this application. High-frequency THD+N may actually be slightly higher with the OPA627. We are using the new LM4562A in the DAC1 USB. The LM4562A is pin-compatible with the NE5532, but you can't just drop it in and get all of the advantages of the DAC1 USB. We changed all of the resistors in the XLR output pads to take advantage of the high drive capability of the LM4562A."

Pay particular attention to items B and D in the list above. The modified units we have seen have incorrect capacitor values substituted for the original parts. Substituting incorrect capacitor values will result in serious deficiencies in sound field accuracy and also freq response accuracy.

Thanks,
Elias

6moons reviewed a modded DAC1, & the reviewer thought it was much improved over the stock DAC1. A lot of owners seem to love their Empirical Audio modded DAC1. I'm sure you frown on modding ingeneral.. I am a DAC1 owner by the way.. & think it's a fantastic DAC..

[kool bubba ice]

Originally Posted by audioengr

If you come to the Head-Fi meet in San Jose you can hear for yourself. I can give you technical explanations about the improvements in person and you can listen to the modded DAC-1. You can hear my new headphone amp mod for it.

Steve N.
Empirical Audio

sounds good..

[boggle]

I am too far away (other side of the world) to take up the Empirical audio offer of listening to the modded DAC1 - I would be interested in what people think though. Again, blind tests are a must. It is pretty easy to hear a qualitative difference when someone is standing there coaching you to hear it (by this I mean we tend to 'hear' differences that are not there). The other thing you need to do to convince is run the stats: get 10 to 20 people to do a double blind AB comparison with the same music and see if we get something significantly (in probability) different from a 50-50 split. I would almost bet a body part that this is not going to happen though.

Suggested experimental design:

Because we are in Headphones the 'double' part of the blind is easily cheated - just get the listener to face away from the source controller.

Switch between sources in some non-standard way. For example start with A for 3 minutes then reset the track and hit them with A again. Restart the track then hit em with B. Continue like this so that over 6 or eight changes there is 3 of each source: eg AABABB. The listener is simply asked to state whether the source he/she hears after the breaks (when we reset the track) is an improvement on the previous source. This will provide clear and convincing data.

If any doubt arises from the results it could be repeated with different music etc..

[kool bubba ice]

Originally Posted by boggle

I am too far away (other side of the world) to take up the Empirical audio offer of listening to the modded DAC1 - I would be interested in what people think though. Again, blind tests are a must. It is pretty easy to hear a qualitative difference when someone is standing there coaching you to hear it (by this I mean we tend to 'hear' differences that are not there). The other thing you need to do to convince is run the stats: get 10 to 20 people to do a double blind AB comparison with the same music and see if we get something significantly (in probability) different from a 50-50 split. I would almost bet a body part that this is not going to happen though.

Suggested experimental design:

Because we are in Headphones the 'double' part of the blind is easily cheated - just get the listener to face away from the source controller.

Switch between sources in some non-standard way. For example start with A for 3 minutes then reset the track and hit them with A again. Restart the track then hit em with B. Continue like this so that over 6 or eight changes there is 3 of each source: eg AABABB. The listener is simply asked to state whether the source he/she hears after the breaks (when we reset the track) is an improvement on the previous source. This will provide clear and convincing data.

If any doubt arises from the results it could be repeated with different music etc..

I'd like to compare the Stock/modded DAC1 with my DVD player & songs I know inside & out..Yes, I need a better CD player..

[Davesrose]

Originally Posted by EliasGwinn

OPA627 vs. NE5532:

The OPA627 will offer no advantage over the NE5532 in this application. High-frequency THD+N may actually be slightly higher with the OPA627. We are using the new LM4562A in the DAC1 USB. The LM4562A is pin-compatible with the NE5532, but you can't just drop it in and get all of the advantages of the DAC1 USB. We changed all of the resistors in the XLR output pads to take advantage of the high drive capability of the LM4562A."

Pay particular attention to items B and D in the list above. The modified units we have seen have incorrect capacitor values substituted for the original parts. Substituting incorrect capacitor values will result in serious deficiencies in sound field accuracy and also freq response accuracy.

Thanks,
Elias

Well shucks.....I've been completely satisfied with my stock DAC1 (it's great as it is, so why mess with perfection?). But now I'm wondering what the sonic differences are between the original DAC1 and DAC1 USB, if you guys changed op amps and redesigned the outputs. I don't use a computer as transport, so I didn't even think about considering the DAC1 USB. If it also offers improved audio for the digital audio inputs, I might just have to keep my eye on this

[kool bubba ice]

Originally Posted by Davesrose

Well shucks.....I've been completely satisfied with my stock DAC1 (it's great as it is, so why mess with perfection?). But now I'm wondering what the sonic differences are between the original DAC1 and DAC1 USB, if you guys changed op amps and redesigned the outputs. I don't use a computer as transport, so I didn't even think about considering the DAC1 USB. If it also offers improved audio for the digital audio inputs, I might just have to keep my eye on this

x2..