Metrum Acoustics Aurix
Feb 6, 2014 at 5:59 PM Post #3 of 284
From the WEB site 
€ 805.00 + 21% VAT ( in EU) Aurix headphone amplifier. Black or silver front.  ( Available end of January 2014)
 
 
 
 
 
When we were requested to develop a headphone amplifier, for sure that had to be something special .
Also the product had to be combined physically with our Octave DAC MKII.
The result is the Aurix. Not an ordinary design like many  but a real improvement on existing principles. Rather than using transistors  or tubes  for amplification a special step-up transformer is used. Said solution solves many problems as known in regular low gain amplifier designs and provides a very transparent sound image. Only two FET transistors are in the signal path as an impedance converter ( source follower, no amplification )  and it is this property were a  FET transistor can do an extremely good job and delivers a very high bandwidth having low noise and low distortion . The first Fet is used as an impedance converter to drive the step-up transformer. The second FET is used to drive the headphone. The circuits are running  in full  " Class A " so that a relatively large heatsink is required to flow the heat . Besides the amplifier part we have used a lot of electronics just for creating the right conditions for the amplifier part and protecting your headphone against subsonics , offsets , pops and clicks. The result is a sound that is mainly determined by the connected source.

 
Output

Max. 6 Volts RMS to 600 Ohm load

 

Max. 2 Volts RMS to 33 Ohm load

Gain

Gain of 1 or 3 (+10dB) selectable by switch on back panel.

 

 

Principle

Amplification using two transistors and a step-up transformer. Current delivery full Class A.  Non feedback design.

 

 

Frequency response

5Hz to 60kHz -3dB

 

 

Distortion

Max. 0.01% THD ,600 Ohm load.

Max 0.5% THD  33 Ohm load.

 

 

Signal to noise

-120 dB related to  2 Volts RMS

 

 

Protection

Start-up Offset and subsonic frequencies.

 

 

Consuming power

Max. 30 VA

 

 

 

 
Feb 24, 2014 at 7:46 PM Post #5 of 284
Looks like an amp for Senns and Beyers rather than orthos and low impedance dynamics. I can only find one review and as it's written by that rather pretentious bloke at 6 Moons and I don't have a thesaurus at hand I'll wait for more info to appear in this thread.
 
Feb 25, 2014 at 9:15 AM Post #6 of 284
Can anybody decipher this nonsense?

http://www.6moons.com/audioreviews/metrum3/5.html

I e-mailed Metrum and asked whether the Aurix is a suitable amp for orthos and low impedance dynamics. They say yes. I'm not so sure. Some specs about the output impedance and current output would be helpful.
 
Feb 25, 2014 at 10:00 PM Post #9 of 284
Output impedance: 3 ohms
Max current: 80 mW

(In case anyone's interested)


Didn't the 6moons guy say the Aurix can drive the HE-6? Totally legit... :p Really though I can think of a few headphones that will be enough for, the Beyerdynamic T90 for example had sufficient volume running direct off my DAC when I had it. Silly question, does the change in output impedance raise or lower the volume? I figure the output on my DAC has a pretty high output impedance.
 
Feb 26, 2014 at 1:22 AM Post #10 of 284
Didn't the 6moons guy say the Aurix can drive the HE-6? Totally legit...
tongue.gif
Really though I can think of a few headphones that will be enough for, the Beyerdynamic T90 for example had sufficient volume running direct off my DAC when I had it. Silly question, does the change in output impedance raise or lower the volume? I figure the output on my DAC has a pretty high output impedance.

Nope, I just took a look at the short 6moons review and he explicitly excludes the HE-6 and AKG K-702 from the test, purely based on specs.  Not much info on the sound except that he mentions a thinner (or 'more delicate' bass).  Surprisingly little info for the rest.  But it's an interesting design.  I like Metrum for their non-upsampling DAC's makes for a refreshing change.
 
May 17, 2014 at 9:27 AM Post #12 of 284
I`ve listened to Metrum Octave + Aurix recently with my 990 Pro. And it was gorgeous! Even if 990 Pro is not a top notch. I know ... The sound was very smooth, dynamic and emotional. Aurix compared to other less expensive amps represents middle frequencies in the best way possible. The sound is not thin but thick and very sweet. No sibilants at all. Everything is so clear and each note is so precise. I liked it more than lehmann black cube, spl auditor, meier concerto, v200 and so on. Metrum is a really unique company indeed.      
 
May 17, 2014 at 10:07 AM Post #13 of 284
I`ve listened to Metrum Octave + Aurix recently with my 990 Pro. And it was gorgeous! Even if 990 Pro is not a top notch. I know ... The sound was very smooth, dynamic and emotional. Aurix compared to other less expensive amps represents middle frequencies in the best way possible. The sound is not thin but thick and very sweet. No sibilants at all. Everything is so clear and each note is so precise. I liked it more than lehmann black cube, spl auditor, meier concerto, v200 and so on. Metrum is a really unique company indeed.      


It was on my shortlist a little while ago but the lack of information and reviews deterred me from taking the plunge. As you're the first person to post in this thread for 3 months, it's probably safe to say that it isn't the most popular amp. Good to learn that it sounds nice though.
 
May 17, 2014 at 11:49 AM Post #14 of 284
It was on my shortlist a little while ago but the lack of information and reviews deterred me from taking the plunge. As you're the first person to post in this thread for 3 months, it's probably safe to say that it isn't the most popular amp. Good to learn that it sounds nice though.

 
Well, it is quite usual situation unfortunately. Good things often dwell in the dark. :) Besides this amp is not cheap so the amount of potential customers is limited.   
 
Jun 20, 2014 at 8:09 PM Post #15 of 284
A few weeks ago i buy this amp. First right out of the box , not convinced. But after playing a lots of hours, sound is wonderful. Together with my Ath-w1000x grandioso its a very highend combi and i never heard better sound through phones. If you had the opportunity to listen to a well burned Aurix, do it. It will surprise you!
 

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