Metrum Acoustics Aurix

[zilch0md]

Oh yes - that's the message of Dan Cheever, in his thesis on negative feedback (above) - and apparently, the message of the well-respected Robert Harley, author of my favorite text on HiFi (The Complete Guide to High-End Audio), as well as the design philosophy of Nelson Pass (revered amp designer) and Cees Ruijtenberg of Metrum:  Measurements aren't everything. Go with your ears!

 

[TokenGesture]

OK - got to say - Octave (Mk1) plus Aurix plus T1 = sonic nirvana.  Full, present, musical, detailed, deep/wide stage , analogue (as opposed to digital), dynamic - wow this combo has it all!  It is the best head fi I have ever heard.
 

 

[zilch0md]

:tongue_smile:

 

[beyerdude]

Just bought the Aurix paired with Octave MKII and HD800 - it's as good or better than my WA6SE with my favourite tubes straight out of the box (and the tubes I use took a LONG time to get the right combination) - it just sounds 'right' nothing in the way of the music, great dynamics, clarity, you can hear every nuance of the music but it never sounds harsh/sibilant - that's before even settling down to do some proper evaluation. Even better none of the low level hum which I normally get from the WA6SE.

 

[zilch0md]

^  Drool!
 
You guys are killing me!  

 

[TokenGesture]

  Just bought the Aurix paired with Octave MKII and HD800 - it's as good or better than my WA6SE with my favourite tubes straight out of the box (and the tubes I use took a LONG time to get the right combination) - it just sounds 'right' nothing in the way of the music, great dynamics, clarity, you can hear every nuance of the music but it never sounds harsh/sibilant - that's before even settling down to do some proper evaluation. Even better none of the low level hum which I normally get from the WA6SE.

 

[beyerdude]

  ^  Drool!
 
You guys are killing me!  

I had to sell part of my vinyl collection to fund it but really the vinyl was just looking pretty on the shelf and the Aurix takes up far less space

 

[preproman]

  Just bought the Aurix paired with Octave MKII and HD800 - it's as good or better than my WA6SE with my favourite tubes straight out of the box (and the tubes I use took a LONG time to get the right combination) - it just sounds 'right' nothing in the way of the music, great dynamics, clarity, you can hear every nuance of the music but it never sounds harsh/sibilant - that's before even settling down to do some proper evaluation. Even better none of the low level hum which I normally get from the WA6SE.

 
Very interesting.  I was just thinking about the WA6SE and was considering getting one.  Would love to hear you comparsions on both. With the tubes you like the most and both with the Octave MKII.
 
Thanks...

 

[beyerdude]

   
Very interesting.  I was just thinking about the WA6SE and was considering getting one.  Would love to hear you comparsions on both. With the tubes you like the most and both with the Octave MKII.
 
Thanks...

Well I now have the Metrum Octave MKII, Aurix and WA6SE all connected up in the same rig - being fed by a macbook pro, Audirvana Plus and a Gustard U12 (excellent usb convertor soundly beats the Hiface1 and Hiface 2.....)
 
Will post you my impressions with a direct comparison rather than an initial thought on separate days....
 
Tubes - Using a German Telefunken G32 Rectifier which SOUNDLY spanks the Sophia Princess (far more refined - the Sophia adds body but at the expense of refinement and also background hum) added bonus is it should last forever as it was designed for military radar on ships (1950's/60's production)  - doesn't look as pretty though.
Paired with a Japanese 6DE7 - very laid back tube, nothing emphasised, good soundstage - will also compare with a few others but this is my pretty much favourite combo - nothing else I have  has the same synergy (and I have about 40 pairs of every type that you can use and most types of rectifier) - has to be Japanese though the RCA US ones I have don't sound the same.....

 

[beyerdude]

I have been swapping between the two for a while now - it's hard to get an instant comparison as the Aurix has a protection circuit which causes a few second delay every time you plug in a headphone.
 
With the default tubes (in my case Westinghouse 6EW7 and the stock chinese rectifier) the Aurix sounds more transparent, slightly better instrument separation, more depth
With my best combination the WA6SE pulls ahead - for lack of a better description the sound is slightly more 'liquid' the bass is more dynamic and overall more 3 dimensional sound - it is not a massive difference - but it is certainly there.
 
Bear in mind my WA6SE took an AGE to burn in and the metrum has had barely 10 hours - I am not sure how much it improves in time - there is not much information on this - if I based it on 10 hours on each device then the Aurix would win hands down. Also the WA6SE is incredibly sensitive to mains power fluctuations here - straight out of the mains (varies between 240 and 263v) the WA6SE loses quite a lot of its edge - the background hum destroys some of its dynamic sound (as it would) - I use a step down to take it down to a far more sensible 225-235v
 
The advantage of the WA6SE is that if you are willing to drop $$$$$ extra on tubes you can have an amp that can be tailored very well to your tastes for pretty much any headphone, also the different headphone outputs enable you to change the sound to a reasonable degree. On the flip side the Aurix sounds not far off as good as my best combo straight out of the box, sits on top of the Octave and also allows me to have a pass through from the octave.---->aurix ---> main pre amp something that the Woo cannot do.....
 
As a cost equation the Aurix cost me $950 AUD delivered (from the US as the local cost was a lot higher and it's an easy conversion from 115 to 230 v), the Standard WA6SE costs $1650 from a local shop here and to get it to the sound I like I then spent a further $1000 on tubes playing around (no regrets at all) - but saying that the tubes are plentiful and cheap - my best tube combo cost $40 for the 6DE7 pair and about $90 for the GZ32
 
I'm keeping both because the aurix will live in the in the lounge and the WA6SE in the study - I also love the look of the WA6SE and it's something I can see my kids coveting when they are old enough to appreciate it.....hell I bought enough tubes to last them and their kids....in the meantime they can use the aurix as there is less potential to destroy tubes.
 
About to try it on a Schitt Bifrost with Uber analogue - might be an interesting comparison!

 

[preproman]

Thanks.  Was that the Octave MKII?
 

 

[zilch0md]

Originally Posted by beyerdude /img/forum/go_quote.gif
 
[snip]
 
Bear in mind my WA6SE took an AGE to burn in and the metrum has had barely 10 hours - I am not sure how much it improves in time - there is not much information on this - if I based it on 10 hours on each device then the Aurix would win hands down.
 
[snip]
 

 
Thanks for your very well-written and "open-minded" comparison!
 
Cees Ruijtenberg (of Metrum Acoustics) is really big on allowing time for burn-in - at least as far as I can tell from his emailed advice regarding the Octave MkII, where he recommended I leave it turned on for a solid two weeks (even without data flowing through it).  
 
I think it safe to conjecture he would agree with your misgivings about having made this comparison after only 10 hours of use on the Aurix, but I wouldn't be surprised to learn later on that the Aurix still falls behind your well-appointed WA6SE.
 
Can you comment more about your previous post's reference to low-level hum in the WA6SE?
 
http://www.head-fi.org/t/689743/metrum-acoustics-aurix/30#post_11059749
 
By the way, I'm thrilled that you're making these comparisons with the HD800.  

 
Thanks!
 
Mike

 

[beyerdude]

   
Thanks for your very well-written and "open-minded" comparison!
 
Cees Ruijtenberg (of Metrum Acoustics) is really big on allowing time for burn-in - at least as far as I can tell from his emailed advice regarding the Octave MkII, where he recommended I leave it turned on for a solid two weeks (even without data flowing through it).  
 
I think it safe to conjecture he would agree with your misgivings about having made this comparison after only 10 hours of use on the Aurix, but I wouldn't be surprised to learn later on that the Aurix still falls behind your well-appointed WA6SE.
 
Can you comment more about your previous post's reference to low-level hum in the WA6SE?
 
http://www.head-fi.org/t/689743/metrum-acoustics-aurix/30#post_11059749
 
By the way, I'm thrilled that you're making these comparisons with the HD800.  

 
Thanks!
 
Mike

Hi Mike,
 
The low level hum is something that is heard constantly through the headphones, regardless of volume - mostly through the high impedance headphone out. It depends on the rectifier used - the sophia princess is about the worst - the GZ32 Telefunken hardly at all. Since using a step down (auto transformer) the hum has all but disappeared so I believe that it is purely a symptom of the excessive mains voltage where I live - up to 265v on a nominal 230v +10% -6% voltage spec
 
I was using a metrum octave mkII @preproman 
 
I plan on giving the aurix a good few weeks before giving real comparisons. My impressions on it are very good - it's one of those amps that certainly don't wow you on initial impressions but a few hours later you realise it has just been faithfully giving you exactly as it should be - 

 

[zilch0md]

^  Thanks for this!
 
Awaiting your follow-up after a couple of weeks or more...  

 

[beyerdude]

  ^  Thanks for this!
 
Awaiting your follow-up after a couple of weeks or more...  

Yeah - actually listening to it now via an X5 as it's too hot here to do anything else! - makes you realise a: how good the line out is out of the X5 and b: its actually a good match to the Aurix - saying that I have the feeling the design characteristics of this particular amp will mean it sounds right using pretty much anything as a source, which is not always the case with some other amp designs.
 
I had the Metrum Octave MkII linked up and burning in for at least 200 hours before I even spent more than a short time listening (on day and night and only brief listen once in a while)
 
My 'Question of the moment' is just how good it would sound with the HE500 - the other headphone meant to be a good match for this amp - Not that I need much of an excuse to try it as I was interested in either an HE560 or HE500 prior to this purchase....