Benchmark V Opus 21

pauldixonuk · « **on:** 27 Mar 2005, 05:11 pm »

Which is best going into ATC active 50's...

1. My existing cyrus dvd8 + benchmark dac1 + atc ca2, OR...

2. Reolution Audio opus 21 cd direct?

I have yet to hear benchmark, but opus is the finest I've yet heard. Will hear benchmark soon, but I'm interested in any experienced users thoughts....

MGDeWulf · « **Reply #1 on:** 30 Mar 2005, 03:02 pm »

My personal preference would be for the benchmark - I've auditioned both extensively. If you decide to audition the benchmark, make sure that the AC line orientation is reversed for lowest AC to ground potential. Big difference sonically. And if someone tries to tell you how the benchmark sounds, and they haven't measured the AC to ground potential, don't listen to them, they don't know what they are talking about with this machine. (or any electrical audio component actually)
Good listening,
Marty

doug s. · « **Reply #2 on:** 30 Mar 2005, 11:09 pm »

Quote from: MGDeWulf

My personal preference would be for the benchmark - I've auditioned both extensively. If you decide to audition the benchmark, make sure that the AC line orientation is reversed for lowest AC to ground potential. Big difference sonically. And if someone tries to tell you how the benchmark sounds, and they haven't measured the AC to ground potential, don't listen to them, they don't know what they are talking about with this machine. (or any electrical audio component actually)
Good listening,
Marty

marty, have you (or anyone?) listened to the mytek dac? a few folks say it's better than the benchmark. mytek actually has stuff on their website recorded by both that can be downloaded for comparison, for those w/the right computer stuff. (not me!)

regards,

doug s.

MGDeWulf · « **Reply #3 on:** 30 Mar 2005, 11:47 pm »

Hi Doug:

I haven't yet heard the mytek. It may be better than the benchmark, but unless those saying the same have checked the chassis to ground potential on the benchmark and the mytek before doing their audition, their results are suspect and cannot be relied upon.

I'll do what I can to get a mytek. Is that the company name? Is there a particular model I shoudl seek out? Thanks in advance Doug.

Marty

doug s. · « **Reply #4 on:** 31 Mar 2005, 02:49 pm »

Quote from: MGDeWulf

Hi Doug:

I haven't yet heard the mytek. It may be better than the benchmark, but unless those saying the same have checked the chassis to ground potential on the benchmark and the mytek before doing their audition, their results are suspect and cannot be relied upon.

I'll do what I can to get a mytek. Is that the company name? Is there a particular model I shoudl seek out? Thanks in advance Doug.

Marty

hi marty,

here's a link to a page from mytek's site, the stereo 96 dac is what i am referring to.

http://www.mytekdigital.com/stereo96.htm

if you scroll down to the bottom of that page, you will find their link to download "Mytek Stereo96 vs Protools vs Apogee vs Protools vs Benchmark" Listening Test Sounds.

they are also releasing shortly (or mebbe it's awreddy on the market?) a new stereo 192khz dsd-pcm dac, but at retail $1995, it's twice the price of the stereo 96 dac. from their oct 2004 press release (on their website under "news"):

"The new Stereo192-DSD DAC converter is the highest performance Mytek DAC yet, aimed at mastering engineers working in both PCM and DSD/SACD world. The DAC includes 1dB mastering precision stepped attenuator, headphone amp and ability to playback DSD over standard AES/EBU hardware."

regards,

doug s.

PhilNYC · « **Reply #5 on:** 31 Mar 2005, 03:06 pm »

Regarding running the Opus 21 direct to an amp; in the past, I was not a fan of doing this. While running direct had many sonic qualities I liked (particularly transparancy and detail), I felt that the overall presentation lacked in other areas that I strongly preferred, including soundstage, bass impact, dynamics, and depth. My preference was strongly in favor of using an active preamp. But recently, after having a dedicated AC line installed in my listening room, I tried running the Opus 21 direct again...and the improvements to bass impact and dynamics was significant. I still have a preference for using an active preamp, but the gap was closed by a good amount, and I can certainly see the appeal of using the Opus 21 in this way much more than I did before.

Also, system matching is also very important for the Opus 21. I've demoed it in a lot of systems, and in some (my own Blue Circle/Focus setup, Cary/Triangle, DNM/Rethm, etc) it has been wonderful, and in others (Talk/Onix, Audiovalve/Von Schweikert) it has been not so great. Haven't found the exact characteristics of a system that make it a good match, so trying-before-buying is important...

So...good AC (dedicated line, good power cord) and system synergy have a big impact on how the Opus 21 performs...

pauldixonuk · « **Reply #6 on:** 31 Mar 2005, 07:28 pm »

Thanks for the detailed and tecchie responses. I've forwarded on the benchmark setup tip - so that will be taken care of when I demo it soon.

Andrew B. · « **Reply #7 on:** 31 Mar 2005, 08:09 pm »

Marty, forgive me but I don't understand your comments on the Benchmark DAC. In one place you say to reverse the AC "line orientation" (presumably here you mean swapping the live and neutral wires in the mains plug) but in another you talk about measuring the chassis to ground potential. Not sure that they are related. We are talking about alternating current here, after all.

Perhaps the confusion lies in the difference between signal ground and electrical (mains) ground (or "earth" as we call it here in the UK).

Please could you explain your arguments and suggested procedures more clearly.

Thanks

Andrew

MGDeWulf · « **Reply #8 on:** 31 Mar 2005, 10:16 pm »

Hi Andrew:

The terms are basically different aspects of the same thing. I shouldn't have assumed that my message was clear.

To me, changiing the orientation is merely flipping the plug in the socket.

The chassis to ground potential is measuring the chassis voltage with the standard plug-in-wall orientation, reversing it, and measuring it again. The best sonics will result with the plug orientation that gives the lowest measured chassis voltage.

It has to do with the way the transformer is wired up inside. Basically, you have a 50/50 chance of your orientation being wrong and having to reverse it in order to attain the lowest chassis to ground potential. I have no idea why manufacturers can't get this right.

If I recall (and don't hold me to this) I measured 52 volts on the chassis of the benchmark with the standard plug-in orientation, and 50 volts with the AC reversed. The 2 volts makes a difference sonically.

But get this with a plinius power amp: 105 volts on the standard plug orientation, but only 9 volts reversed. Had to flip that plug. Have never measured a bigger difference. I have measurements going back 10 - 15 years on everything I've listened to.

Hope this helps...
Marty

JoshK · « **Reply #9 on:** 31 Mar 2005, 10:33 pm »

Marty,

Call me daft, but I am still not clear what you mean by chassis voltage, I get you are measuring the voltage on the chassis, but relative to what? Neutral? Certainly not Earth, because that *should* be ~0.

Andrew B. · « **Reply #10 on:** 31 Mar 2005, 11:07 pm »

I'm as daft as Josh.

Are you saying that if I take my multimeter and measure between the chassis with one probe and signal ground (at the output phonos or XLRs) with the other probe, I might find a voltage as high as 50 volts? And if I were then to swap the live and neutral wires in my mains plug (since we can't just flip the UK plugs) and make the same measurements then I would get a different result? And that the different result, being a higher or lower potential between signal ground and chassis ground, would make a sonic difference? Even with a balanced XLR output?

I can understand the importance of a SYSTEM having a single common reference mains ground (aka earth) to avoid creating a potential between the different earths - leading, in its grossest form, to loud hums in PA systems - but I am not so clear on the position here and indeed whether this is the problem that you are trying to address. I'm looking forward to understanding more.

Thanks

Andrew

Andrew B. · « **Reply #11 on:** 31 Mar 2005, 11:27 pm »

To clarify this, it might be helpful if we distinguish between:

(1) Signal ground;
(2) Chassis ground; and
(3) Mains earth

Could we try to use those terms precisely in order to make the discussion clearer?

Thanks

Andrew

MGDeWulf · « **Reply #12 on:** 1 Apr 2005, 04:13 am »

Hi Josh:

You're not daft, I'm just not doing a very good job of describing my procedure. It's like this: Hook up the benchmark to an AC outlet. Lift its ground. Get a voltmeter; set to volts AC. Ground the black probe. Turn the benchmark on and touch the red probe to a screw on the chassis or to the outside of an RCA jack on the benchmark. You will get a voltage reading. Turn off the benchmark. Reverse the orientation of the plug in the wall, ie., flip it. Turn the benchmark back on and touch the red probe to the same chassis screw as you did before. You will get a different volt reading this time. This is checking the chassis to ground potential. You want to go with the lowest reading.

I hope this helps. There is an article on my website that I wrote years ago that explains the whole procedure in better detail. I think it is in the archives under "AC and You."

Is it okay to put a link to my website? I'm not sure, I'll wait until I'm sure that I'm not breaking any rules. You should be able to get by on what I said above.

Good listening,
Marty

pauldixonuk · « **Reply #13 on:** 1 Apr 2005, 03:20 pm »

MGDeWulf, thanks for the ongoing explanations. I've never heard of this and wonder how many people out there are also in the dark? I'll definately give it a go. Please post up your website or mail me the link to....

p_vantage@yahoo.co.uk

Thanks!

MGDeWulf · « **Reply #14 on:** 6 Apr 2005, 01:22 pm »

This is the link to my description on how to check for properchassis to ground potential....http://www.boundforsound.com/tweak.htm

If the link doesn't work, it's because I don't know what I'm doing.

Marty

Occam · « **Reply #15 on:** 6 Apr 2005, 02:41 pm »

Marty,

Many thanks for the link to the polarity article. My diy equipment all have a dpdt, center off switch, that makes reversing AC polarity quite easy.... The most radical effect of AC plug polarityI've found was the Art DI/O with an outboard Stancor or Atari 9v AC transformer. The changes wrought with proper orientation was stunning.

Your link also includes your article 'AC and You - a New Era'. In the 8 years since you wrote it have your conclusions changed? Specifically, with the advent of many balanced AC transformers/conditioners, do you still think transformers as generally negative?

TIA,
Paul

konut · « **Reply #16 on:** 6 Apr 2005, 03:05 pm »

Marty, as long as you're in the comparison mode, I'd like to suggest the Lavry Blue http://www.lavryengineering.com/index_html.html Its been reviewed very well in the pro audio world and is usually mentioned in comparison with the Benchmark, Mytek, Apogee Mini-Dac. Its a bit more at $1325.00, but it usually gets the nod above the aforementioned competition.

Andrew B. · « **Reply #17 on:** 6 Apr 2005, 04:20 pm »

Our plugs here have proper AC grounds and lifting these is dangerous and therefore not advisable unless the component is double insulated (ie has no earth connection). Given that the AC ground is always connected I do not see why one should take a measurement of the chassis voltage relative to some other ground.

What assumptions are you making about signal ground, chassis ground and mains ground/earth? And, to repeat my earlier question, why do you think your tweak would have an effect - what would be the cause of such an effect?

I would have thought that proper system earthing was far more important - in other words having a common mains ground, independent chassis grounds and a common signal ground derived from one source. I have a balanced preamp and balanced active speakers. And my CD transport is double insulated so it has no mains ground connection. So the only troublesome point in the signal chain with respect to mains ground is the Benchmark DAC which has an unbalanced connection to the preamp. But the DAC and the preamp plug into the same distribution block so the potential between their two mains grounds must be very low indeed (I am assuming from your description of lifting the AC ground from the Benchmark that the Benchmark is not double-insulated and so it does in fact make a connection to AC ground).

Andrew

Occam · « **Reply #18 on:** 6 Apr 2005, 05:49 pm »

Andrew - I think you may have misread MGD's intent. The lifting of the mains ground is only for the purpose of measuring chassis to mains ground potential. After the line/neutral connection is oriented to minimize this voltage potential,the cheater plug is removed, so the mains ground is still extant and saftey precautions are not compromised.
From the article -

Quote

Some audiophiles, when reversing a power cord, choose to leave the ground open or floating, alleging that the system sounds better that way. In some cases it is true, but remember, by floating the ground you may be defeating the UL rating for the device and maybe even voiding the warranty, which could be disastrous if for some reason a fire results. Play it safe.

Pehaps Marty should have altered 'Play it safe' to "Regardless of whatever your feeling are towards electircal standards and codes, the lifting of a mains ground can endanger people and property. Don't be STUPID!"
But then again, MGD acted responsibly with his cautionary statement and his not drubbing us with the safety screed, might simply be an effort to promote Darwinism......

MGDeWulf · « **Reply #19 on:** 6 Apr 2005, 08:54 pm »

By writing the article, it was not my intent that all persons reading it defeat the ground on their equipment and thereby create a dangerous condition. For testing purposes only, the ground must be lifted on the unit being tested as it is tested. After the testing is completed and the lowest potential as been determined, reinstall the ground. I probably should have been a little more clear.

I didn't want to shock (get it?) Andrew with the ground-lift requirement during testing, but I think Occam did a very fine job of explaining what I meant. Thank you very much Occam.

Marty