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Metrum Octave NOS Mini DAC


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*Caveat - Currently my best listening rig is the Lyr tube/SS headamp and AKG K701 headphones. I'd love to have a decent dedicated 2 channel loudspeaker system and currently I don't think my speakers and HT amp are good enough to reveal the subtleties of DACs and formats as well as my headphone rig does. My room is also too bouncy for my liking, ok for fun with 5.1 but even with that format I note many downsides. I realise many folks looking for a DAC are mostly using loudspeakers and amps for their playback, so horses for courses with these notes, read into this what you will.

I come to the Metrum Octave Mini DAC with only having owned one other DAC, the Beresford Caiman so my comparisons and evaluations are somewhat limited, other than using no DAC at all and varying levels of quality in traditional transports. There's other folk out there who have made broader comparisons that you can delve into, this is just one man's small review.

The oft-made comments of the Octave are transparency, clarity and definition. I've found these to be accurate (no pun intended). I think focus is another you could use, it's similar to those other words. When you concentrate on the sound or even when you find yourself being involved, it's the focus on instruments, vocals and space between them that stands out, the depth of the fidelity - the body of the meat. When I revert back to the Caiman, I find there's less being revealed, the glasses are foggier. There's not so much a veil missing with the Octave than an increase of magnification, which isn't an increase in volume as you might conclude. It's higher definition, or a more focussed resolution. Which is kind of amazing to me. I remember first hearing the Caiman and thinking, "Wow, this detail has always been there in the source but it hadn't been resolved this much before." The Octave is another step up in the resolution chain, how much more than other DACs out there I can't really say but against the Caiman, it's defining instruments in spades, showing the space between elements in a mix, with ease. I had a similar realisation with the Audiophilleo 2 and Caiman, the AP2 improved focus, improved the definition but the Octave takes this further.

The first thing I noticed was a lower noise floor and I mean waaaaay lower than I've heard before. Amazing. The Caiman was delivering more noise than I'd realised (this after using the AP2 for some time too which I found to be another improvement in dynamic range). This lack of noise definately changes your perception of the presentation, I guess it's due to it's dynamic range being greater. At times I've had to adjust the volume so there's definately broader dynamics. Perhaps the power supply being separate from the DAC unit contributes to this? (I'm running these side by side, as far apart as the somewhat short 5V cable allows).

Next I noticed more bass, definately more bottom end and better bottom end at that. A little EQ still required for the 701's (for me) around 60-160Hz, but less than previously with the Caiman inline. It's lower bass than the Caiman too, more of it and with a steadiness that is impressive.

Third was the clarity of the subtleties. It's astounding. I'm simply closer now to the recording/mix/mastering engineer's intentions and realisation of the music than ever before. In comparison to the Octave, there is a hollowness to the presentation of the Caiman. The detail and crispness isn't bad but there's sort of a hole. Not over the top, not super obvious but between noticeable and a subtley. On switching back and forth between DAC's (which isn't instantaneous but reasonably quick~30 secs or so) you notice these subtlties without much effort. Metrum accuracy reigns.

Upsampling of 44k material to 176k offers some further reduction in background noise, some more clarification of fine detail. But these differences I have found to be mild compared to the Octave/Caiman differences, the mildest being 96 upsampled to 176, there's really not a lot in that. Also, this unit appears to go to 176k only as opposed to some owners finding 192k playback possible.

The first owner of this DAC suggested less than 50 hours use had been racked up (I'm calling it 40 hours for logging purposes). I've not read a definite figure that should see it burnt in, one of the first members of SNA to own an Octave hasn't heard any change in it's sound since new, yet Cees at Metrum Acoustics suggests 600 hours on the Octave simply being switched on is the benchmark, so who knows? I've previously been skeptical of SS gear changing it's sound over time, however I've found the Octave changed after putting a further 70 hours on it (110 in reality), mids smoother and filled out a little more. HF extension seems smoother also, more mature but not recessed. Well recorded percussion, strings and vocals sparkle.

After rolling the Jan 6922's into the Schiit Lyr for a comparison I was surprised to not notice the lush mids in them like I used to. I did notice a lack of tops and also of bass. Perhaps it was those characteristics that emphasized the mids afterall? I tried the GE 6BZ7's and liked the top end but found them a bit thin, lacking mids. Wider staging than the 6922's but bass a bit lean too. Rolling the Philips E88CC's back in and it's immediately evident why I love these tubes, they have everything in even servings; lower lows, crisp and airy tops and the mids that vocals deserve. The presentation of detail is quite amazing and that's the key to the Metrum Octave DAC - that attribute recalled again, that the focus is its strength.

When listening to the rig as a whole in the mornings, after some warm up of the tubes and an overnight of running the DAC (with input signal) I go through a few tracks, tracks I know pretty well to evaluate this combo's presentation. What strikes me is how right it sounds, how much I'm enjoying the music. So much more detail in vocals, words announciated, the completeness of sounds such as reverbs and subtle 'back there' echoes. Saying instruments and vocals are so much more 'real' is so common in reviews of gear, particularly DAC's but how else do you describe exactly that?

The Metrum does reveal poorly recorded/mastered material though, it isn't a totally magic box: rubbish in = rubbish out. But it's accurate rubbish. Some prefer a transport like the JKMkII/III over the AP2, I can imagine perhaps further roundness or slightly less crisp tops from that combo if it can be said that the John Kenny converter offers a thicker air, it may be something I look at for curiosity down the track but if I was forced to settle with the AP2, I'd be happy as a pig in sh*t. Though I am sorely tempted to try an Off Ramp as it's an impressive suggestion/reality that it trounces the other two converters. What more can it do that the AP doesn't? I would love to hear to then know.

Before I sold the Caiman I again made a few quick comparisons as mentioned above. My initial impressions remained - the same differences stood out. At a total of 550 hours of use now, my experience with the Metrum so far means I have decided on my goal in all this searching, listening and comparing. I want accuracy and transparancy. In a way, I want to hear the faults of the recording, because that brings so much kudos to the really well recorded, mixed and mastered music I love so much. I want to get as close to the engineers' intentions as I can (within a budget, a budget which is perhaps chump change to many out there...) Whether a proper room and speaker combination would offer similarly pleasing results I can't say, I hope some time not too far down the track to find that out, but the idea of having this kind of accuracy in the signal before an amp and speakers is pretty exciting for me.

*Second caveat - I've written this to add to the reports and info that is out there on the Metrum Octave for potential buyers or folks who aren't sure of the more technical perspectives. I'm not up for an argument over software used, other hardware or this and that or anything else. It is what it is, a collection of my impressions. I hope it's a worthwhile read, if it's not one thing or another enough, then ah well.

Edited by LuzArt
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Yeah a good write up. I haven't heard any thoughts of the metrum from a headphone user's perspective so I found that interesting.

I also appreciated your thoughts/experiences re. tube rolling for the schitt.

I have wanted to hear one of these for a while.

Cheers,

James

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Thanks for a nicely crafted contribution, LuzArt.

I'm appreciating my Metrum/AP2 combo immensely. Lately have been doing NOS, digital volume control and direct connection to power amp for the most immediate, dynamic, honest-sounding results I've heard from any products at that price range. Having total control over the digital realm - no in-built upsampling or filtering etc in the Metrum - gives you enormous flexibility.

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Thanks for the replies, appreciated.

As a follow up, I'm currently listening to the AP2/Octave combo with Nada's USB battery pack mod. I'm using regular alkalines while the rechargeables charge but I have to say, I am impressed. A noticeable drop in noisefloor, which is remarkable given how far I've heard that floor drop via changes from the Caiman/Musiland combination to the Caiman/Audiophilleo2 and then to the Metrum. Similar to JD's review of the KingRex UPower unit, there is a taming of the extended highs that are delivered by the AP2/Octave rig. Not overly so but in quiet passages, it is evident how less noise/tape hiss/mic preamp noise there is.

A worthwhile, cheap DIY mod to squeeze even more joy from these toys :)

Edited by LuzArt
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Interesting write-up. I can definitely understand the desire to have accuracy and transparency.

I have the Vaunix lab-grade hub powereing my AP1, which has been great, as it works flawlessly with my iPad as the transport. Thought the Octave has settled down considerably, comparing it to my Reference 7.1, the soundstage is narrower, even using high-res files or up-sampling (using Pure Music or an iZotope-powered up-sampler). It still, however, seems to emphasise instruments that are more in the background -- maybe that's an artifact of the smaller soundstage along with the clarity. I need to experiment more with different amps, as each one I have has different degrees of sensitivity to the output of the source.

Edited by Currawong
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Interesting write-up. I can definitely understand the desire to have accuracy and transparency.

Thanks.

I have the Vaunix lab-grade hub powereing my AP1, which has been great, as it works flawlessly with my iPad as the transport.

Interesting. Does this mean the iPad is located close to the hub and it's not as 'portable' (using it on the couch). I still use a laptop which sits near my gear. I use a iPhone app for foobar but would love to use a pad with more flexibility.

Thought the Octave has settled down considerably, comparing it to my Reference 7.1, the soundstage is narrower, even using high-res files or up-sampling (using Pure Music or an iZotope-powered up-sampler). It still, however, seems to emphasise instruments that are more in the background -- maybe that's an artifact of the smaller soundstage along with the clarity. I need to experiment more with different amps, as each one I have has different degrees of sensitivity to the output of the source.

Wow, even broader soundstage, very nice.

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Have to add this. Tried to get to bed an hour ago, just can't stop listening :) Been through some Kings Of Convenience, some Eagles, Steely Dan and now some John Mayer. This battery mod has improved bass response too, I've knocked back the EQ some, not as necessary as previously. There's a better cohesion between all sounds, definately more of a smoothness and roundness. Even compressed stuff (Mayer, a touch squashed) breathes better.

Edit: now making the last track John Martyn's Over The Hill. Magic!

Edited by LuzArt
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  • 7 months later...

Just be a bit careful using the Metrum straight to power amp. Any signal unlocking can mean white noise at full amplification and tweeters instantly shredded.

Also the output of the Metrum lacks a discrete stage and current buffer. Its not that robust being driven only by charge pumps. From the little I heard the Metrum sounded better going into a valve pre to do the power driving duties. I also think tubes go well with the Metrum to flesh out the mids and tame that forward lean. Mind you Ive never lived with it so these are likely superficial and misleading impressions :)

Edited by Nada
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Just be a bit careful using the Metrum straight to power amp. Any signal unlocking can mean white noise at full amplification and tweeters instanlty shredded.

That's scary - would this apply also to the NAD M51? I'm currently running this into the power amp section of a Ming Da MC34a and it sounds very good indeed. But I definitely don't want to shred any Yamaha beryllium tweeters :(

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My Metrum has never made any noises that it wasn't meant to. Going direct to power amp with any DAC that doesn't have internal volume control is always a bit of a risk, but with this DAC I haven't come across any white noise that would blow my tweeters.

That said... I have eventually settled for various reasons on using my integrated amp as it was designed to be, rather than relying on digital volume control and plugging into the HT bypass inputs.

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...Going direct to power amp with any DAC that doesn't have internal volume control is always a bit of a risk, but with this DAC I haven't come across any white noise that would blow my tweeters.

I think youve got the AP2 and superb IT skills to keep your DAC from unlocking. As good as the metrum is I think its down to the way you run your audiophilleo that keeps it controlled.

That's scary - would this apply also to the NAD M51?

Doesnt the NAD have its own volume control with a remote? Internal volume control should be safe.

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  • 1 month later...

Great review, LuzArt! I've had my Octave for about a year now and am still loving it. The depth of sound, clarity and dynamics are outstanding. I sometimes use it directly connected to my Graham Slee Solo UL head amp, with HD650s, and the sound is stunning.

I'd like to hear Cees' new Hex DAC. But that's in another price league altogether . . .

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Yes I agree Morris minor. There's still a few bands of affordability and the Hex is aiming much further up than they did with the Octave. Given the performance of the Octave, my opinion is they've realised they under priced by a significant margin. The quality for that money really was outstanding, so I think they're trying to maybe even compete against themselves. Surely the Hex is

a lot closer to the pointy end of diminishing returns...

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