[Iron_Dreamer]

Quote:

Originally Posted by slwiser /img/forum/go_quote.gif Question for you electronics trained people out there. Is the balanced ground concept anything else than what is used in measurements where you have "phantom power" or an imposed current to keep noise down?

I don't think so, I think what Dr. Meier is terming "balanced ground" is akin to what has been done in the past with 3-channel amps like the M3, PPA, etc. The ground channel of the amp sources/sinks the return current from the headphone drives, with a much lower impedance than what could be attained with a passive ground, the result being less inter-channel crosstalk (though not as low as with a balanced amp, where both channels are completely separate). As such, a 3-channel amp theoretically can extract more sound quality from headphones than a 2-channel, while not requiring retermination/recabling as a balanced amp would.

 

[slwiser]

Thanks, I had been wondering what the meaning of this balanced ground was.

Quote:

Originally Posted by Iron_Dreamer /img/forum/go_quote.gif I don't think so, I think what Dr. Meier is terming "balanced ground" is akin to what has been done in the past with 3-channel amps like the M3, PPA, etc. The ground channel of the amp sources/sinks the return current from the headphone drives, with a much lower impedance than what could be attained with a passive ground, the result being less inter-channel crosstalk (though not as low as with a balanced amp, where both channels are completely separate). As such, a 3-channel amp theoretically can extract more sound quality from headphones than a 2-channel, while not requiring retermination/recabling as a balanced amp would.

 

[silverrain]

Quote:

Originally Posted by laxx /img/forum/go_quote.gif I will most likely be picking one of these up for a friend, an Opera and a Headroom Max Amp as well. I'll post my reviews, and hopefully, neither will put my Aria to shame that much as I don't want to blow all of my tax returns on another amp. =T

Please post a short comaprison, later?

 

[LouT]

Is there a way to utilize the s/pdif from my laptop?

I use a mini plug to rca cable. The sound card just needs to have a digital out that leaves the signal raw.

You could buy an external soundcard too I guess and plug that into the laptop via usb.

 

[arnaud]

I have received my Opera this week and played a bit comparing the internal DAC to my faithful Meridian 508 CDP. I mostly used AKG 701s received with the amp. Both the Opera and K701s had 200 hours burn-in when I received them, closer to 300 now. I am not using the cross-feed and the music played ranges from Jazz to Rock. I haven't listened to Classical just yet with this combo. The headphones (also used my Zu 650s a bit too) are plugged in the 0 ohm output.

I have to admit I had some preset ideas about how the comparison would turn out. I was indeed much hoping for the iMac/USB output to out-perform my old CD player. The Opera sits next to the mac so it's just so convenient...

Unfortunately, the result is not quite what I wanted so far as here is how I would rank the sources in order of preference:
1. 508.24 line out -> Grover UR2 -> Opera
2. 508.24 coaxial out -> standard cable shipping with the amp > Opera
3. iMac / Itunes -> standard USB cable shipping with the amp > Opera

Before I elaborate a bit more on this, here is why my comments should be taken with a pinch of salt:
1. The differences are really not dramatic and I believe I would love the Opera with the computer, had I not dared compare it to the Meridian...
2. Some of these preferences may be related to synergy with the headphones: I might by unconsciously preferring the warmer sound of the Meridian with the K701s because they are not fully burned in yet and still a on the bright side. I have spent a bit of time with the HD650s though and also preferred the Meridian line out above all.
3. Some of the differences might be accentuated by poor volume matching. Indeed, all three outputs yield different loudness (508 line out is louder than coaxial out which in turn is louder than USB input from the computer). I try to adjust the volume when switching sources but it ain't easy...
4. Given how subtle the differences are, I wonder how much the cables are responsible (digital coax, Grover UR2s).

When comparing Opera's DAC and the 508 DAC (1 vs. 2), the latter has more body with warmer voices while sounding clearer, more impactful, simply more real.
When comparing the 508 digital out to the imac (2 vs. 3), the former sounds cleaner (the imac/USB sounds like it's smearing the highs at times), more extended in the highs, much more dynamic/punchy and has a more palpable soundstage.
So somehow, I observe the same kind of degradations when going from 1 to 2 and then 2 to 3...

So, I guess I will hang on to my 508 for a little longer... Now, in regards to the amp itself: well it simply sounds fantastic! So extended in both ends, tight grip on both the AKG and Sennheisers, very dynamic, so much punch in the bass, never harsh or brittle. I had a Prehead MkI a few years back and the Opera is miles ahead! I love it!

Next step will be to compare to the Stealth...

arnaud.

 

[Absolute0]

Quote:

Originally Posted by arnaud /img/forum/go_quote.gif I had a Prehead MkI a few years back and the Opera is miles ahead!

Anyone else compared the Prehead MkII SE to the Opera? There were some posts in front but the comparisons were brief and inconclusive. I am having a hard time deciding between the two.

 

[Jan Meier]

Dear Headfellows,

Just to solve some misunderstandings:

> "balanced ground" is akin to what has been done in the past with 3-channel amps like the M3, PPA, etc. The ground channel of the amp sources/sinks the return current

NO! Balanced ground is not equal to active ground like on the M3 or other amplifiers. With balanced ground the electrical potential of the ground channel is not kept at zero Volts but varies to keep the summed potential of all connection wires at zero Volts. The difference is quite dramatic really. During the design phase of the amp I made a prototype that allowed to switch between passive ground, active ground, and balanced ground. The difference between passive ground and active ground was actually small when compared to the difference between active ground and balanced ground. The concept of balanced ground really does make a difference!

Cheers

Jan

 

[Nietzsche]

Arnaud, good comments.
I agree:the amp is really very good. The internal DAC sounds middle of the road to me. A good CDP in the > 1500 EURO range wille provide in almost all cases a better internal DAC (it's also more expensive).
The Opera's internal DAC is a handy solution for resources with only a digital output, or a mediocre DAC, but it's not an upgrade to "high fidelity" (but the margins of this connotation can vary widely from person to person) CDPs.
I should not buy the Opera just for the DAC.
But it's a very good amp absolutely worth its price, and for that price you can consider the internal DAC as a free extra that you probably don't need unless you hook it up to a computer (personally I've never heard any computer source sounding good enough for hifi, nor any MP3-format source - ahhhh shoot me!).

 

[JaZZ]

Quote:

Originally Posted by arnaud /img/forum/go_quote.gif Some of the differences might be accentuated by poor volume matching. Indeed, all three outputs yield different loudness (508 line out is louder than coaxial out which in turn is louder than USB input from the computer).

Coaxial and USB input should provide the same volume level. If not, you don't get the full 16 bit from the USB source. Check the computer settings!
.

 

[Patu]

Quote:

Originally Posted by milkpowder /img/forum/go_quote.gif DA100/HP100: {[$1370 + Import Duty (3.5%)] + VAT (17.5% of shipment value & import duty)} + DHL Admin fee (2% of shipment value) delivered TOTAL 890.70GBP by Paypal Opera: 975EUR delivered TOTAL 666.85GBP by Paypal

Well the difference definitely wasn't that big in my case. I was lucky with the customs this time.

Let's say that they're ALMOST in the same price range.

 

[slwiser]

The opera sounds like a killer device. It has a DAC, Amp, USB converter all in one. Wonder if he used the SPDIF chip to convert the USB signal or an I2S interface. AudioEngr has shown that the I2S can be a real upgrade in quality if done properly.

 

[onecm]

Quote:

Originally Posted by slwiser /img/forum/go_quote.gif The opera sounds like a killer device. It has a DAC, Amp, USB converter all in one. Wonder if he used the SPDIF chip to convert the USB signal or an I2S interface. AudioEngr has shown that the I2S can be a real upgrade in quality if done properly.

You forgot the excellent pre-amp lol, ours is performing very well. Like the headphone amp, it's very transparent with only a slight touch of warmth, so it's probably best suited to systems with some warmth somewhere else in the chain.

Arnaud: Maybe try some different digital cables if you can. I'm sure the results will be interesting, although will not necessarily make improvements comparible to your 508's line out.

Comparing a cardas neutral reference analogue IC with a cheaper copper coaxial cable changes the sound significantly, warmth, tonal balance and imaging are all affected. I would be interested to hear what a well regarded, high quality digital IC could do... But my budget has extended only to a second hand stereovox HDXV which is in the post.

 

[LouT]

The usb volume vs. my cd player are exacly the same. Both usb speaker volume set to 100% and WMP set to 100%. The comparison was difficult while I had them set to 60%, with the louder allways being the better of the two.

Crossfeed on or off will not make any difference since it will affect both equally, as will the 0 vs 120 output. I use 120 with stock cable 650's. Oh and the far right gain switch...Jan mentioned less gain being better...but if you need more volume there is not much choice here. I use low gain and 12 to 1 ish o'clock.

If the digital signal is weak (volumes not set at 100%) the results ariving at the operas dac can be degraded. (mentioned in Operas handbook)

I am not running out using my cdp as a transport either, but while hooked up to a pc the results are pleasing. Nice bonus for an amp that could be sold as a stand alone amp in this price range.

Lou

 

[arnaud]

Jazz and LouT,

Looks like something's not quite right with my computer as the USB is at last 3dB lower than when using coaxial output of the CD player. I am not too savvy (hence having a mac

), but I did maximize the volume in both itunes and the sound card control panel. Not sure where to go next...

Any proficient mac users here?

Arnaud.

Quote:

Originally Posted by LouT /img/forum/go_quote.gif The usb volume vs. my cd player are exacly the same. Both usb speaker volume set to 100% and WMP set to 100%. The comparison was difficult while I had them set to 60%, with the louder allways being the better of the two. Crossfeed on or off will not make any difference since it will affect both equally, as will the 0 vs 120 output. I use 120 with stock cable 650's. Oh and the far right gain switch...Jan mentioned less gain being better...but if you need more volume there is not much choice here. I use low gain and 12 to 1 ish o'clock. If the digital signal is weak (volumes not set at 100%) the results ariving at the operas dac can be degraded. (mentioned in Operas handbook) I am not running out using my cdp as a transport either, but while hooked up to a pc the results are pleasing. Nice bonus for an amp that could be sold as a stand alone amp in this price range. Lou

 

[Iron_Dreamer]

Quote:

Originally Posted by Jan Meier /img/forum/go_quote.gif Dear Headfellows, Just to solve some misunderstandings: > "balanced ground" is akin to what has been done in the past with 3-channel amps like the M3, PPA, etc. The ground channel of the amp sources/sinks the return current NO! Balanced ground is not equal to active ground like on the M3 or other amplifiers. With balanced ground the electrical potential of the ground channel is not kept at zero Volts but varies to keep the summed potential of all connection wires at zero Volts. The difference is quite dramatic really. During the design phase of the amp I made a prototype that allowed to switch between passive ground, active ground, and balanced ground. The difference between passive ground and active ground was actually small when compared to the difference between active ground and balanced ground. The concept of balanced ground really does make a difference! Cheers Jan

Ok, thanks for correcting me. I got the impression from the material on the Opera that is was an active ground design, and that calling it "balanced ground" was an effort to put your own unique marketing spin on the design. It's interesting to know that it takes things even a step further than active ground. I look forward to hearing it in action.