Metrum Octave Dac - What are the Chips used

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A little bit of sleuthing and it seems to me to be a DAC8581, the 4 ground pins are a giveaway, anybody with this dac and a multimeter should be provide confirmation?

Best pic I could find, just cropped and enlarged

Now to hunt down some Sasquatches :)

love the ninja hehe, yeah that was the best set of pics i could find too, he really should look into getting them professionally soldered. looks like he got the dac chips loaded but soldered the passives himself in a less than professional manner, far far too much solder; Mr Blobby pants. Otherwise the layout looks quite good and i'm a fan of the polymer tantalum caps hes used. One thing I cant figure out, is why he went to all the trouble of having a separate PSU case and then didnt have the rectifier in it, instead bringing AC in on the umbilical :confused:
 
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love the ninja hehe, yeah that was the best set of pics i could find too, he really should look into getting them professionally soldered. looks like he got the dac chips loaded but soldered the passives himself in a less than professional manner, far far too much solder; Mr Blobby pants. Otherwise the layout looks quite good and i'm a fan of the polymer tantalum caps hes used. One thing I cant figure out, is why he went to all the trouble of having a separate PSU case and then didnt have the rectifier in it, instead bringing AC in on the umbilical :confused:

I noticed the blobs too, looks like handiwork to me and not like it's been reflowed.
Perhaps the pics are of a prototype or a small pre-production series.

Unless the pic on his website under "Background information->Manufacturing and testing the mini dac" is just for show, it looks like a professional environment. The ESD mat on the table and the white coat are some of the signs. The mention of an "anti static zone" (we'd call it ESD Protected Area) also doesn't hint at it being made in a shed. Don't think they're using an Audio Precision, though...
 
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I think it bares mentioning that there will always be two schools of thought with regards to things like this. Those that take the 'engineering' point of view of 'I want the signal to be as clean as possible and therefore as untouched by the equipment as possible' and then those that don't care and simply go for what 'sounds best'.

Sounding best often includes 'stuff' that degrades absolute linearity and therefore isn't truly neutral, but as it sounds better that's all that matters.

It is pointless in trying to convert someone from one way of thinking to the other. Sometimes one will change their way of thinking as they shift from a casual DIYer to someone with more of an interest and go from being Mr Subjective to Mr Objective-engineer and sometimes one will try and incorporate both into their design philosophy.

I personally would never buy this DAC as it goes against my way of thinking, but I'm certainly not going to bash anyone else for buying one and thinking it sounds great, as to them it probably does. To highlight what I mean by this though, is that having this DAC in my system would sit badly in my mind. I would not enjoy the music because it's measured performance is seriously mediocre and that in and of itself would be enough alter my perception towards dislike - I would not be happy using it.

I know that chasing out the bugs in a specific design, so that it goes from 0.00x% distortion to what it's truly capable of, down at 0.000x%, is likely to be imperceptible, but I will get far more enjoyment out of listening to the product with 0.000x% because I know that it has been designed correctly (I am speaking in terms of my own designs here).

This is what a lot of high end audio is all about though and what satisfies one persons idea of the perfect piece of equipment is often vastly different to someone else's idea of perfection.
 
Well just because two people prefer two completely different DAC designs doesn't mean that either of them are deaf, all it shows is that they have different listening preferences.

I mean there's bad sound and then there's really bad sound. Where the former simply means an overall high-quality system that is simply tuned to something not of your liking. The second being some 2 watt filterless class D chip amp clipping at 20% THD into some tiny speakers, with an absence of either end of the audio spectrum and then pushed beyond their xmax.

If someone preferred the latter there then yes, that's a scenario where you can say someone is deaf. But where reasonably subtle differences are involved it's harder to simply say 'your deaf' instead of really saying, I do not share your taste in audio reproduction.
 
Nice pic, and here's the one from the Hifi Critic interview (I assummed it's the same as your's with the 19/20 kHz testtones). I'm sure if I were to use the AP we have at work, I'd come up with the same results.
The FACT is that 16 bit 44.1kHz NOS filterless is horrible.
CD reproduction was never ment to be NOS. Using a 24 bit 192kHz signal is equal to a very good 4x OS applied to the CD (better than what a DAC can OS from 44.1). And as you could see, at that sample rate, the filtering requirements are way lessend.
PS: I don't know if you have the capability (good ADC) to make some measurements on your new NOS filterless (is that true filterless?) DAC and post them here - I would definitelly trust them more than a typed poem.
 
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But how do you feel when you are called deaf because you don't appreciate their non-filtered DAC? Especially when you don't talk of 0.000x% difference but more like 5%.

Wouldn't it be crazy if we were all fairly deaf and the whole high end audio industry was built on the power of suggestion and chasing ghosts?

But seriously, the fact is that there are many products out there that are hack jobs from a technical standpoint which get excellent reviews. The logical conclusions are either that a large percentage of "audiophiles" are either deaf, or that there are yet unexplained types of distortion which are audible but have evaded measurement for the past 40-odd years.
 
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I'd rather take the view that we're all rather deaf. Humans are notoriously bad at certain things and something like 'audio analysis' is definitely one of them, one reason for this is that our emotions are highly involved with our hearing. By nature we are creatures of choice and love variation in pretty much all aspects of life. We have loads of phrases from different cultures and different languages to the tune of - one mans... is another mans... etc. Audio is no different, I mean just look at the vast quantity of different styles and genre that exist, we all prefer listening to different things.

Measurements will probably confirm, on the whole, that there will be a trend among listeners, that we all prefer music to be reproduced in the same way. Things we can pretty much all agree on, like clean amplification (ie non clipping), low compression in the loudspeakers, a non-fatiguing sound and probably full 20-20k reproduction or something. What measurements can't do is say that person A prefers a gentle amount of bass boost from 20-80Hz and person two prefers it without.

Some piece of equipment might measure poorly, but as long as that poor measurement doesn't inherently sound unpleasant, then any bad measuring piece of equipment will gain fame with certain people because they prefer the way that thing sounds.

Is this a bad thing? Well it depends on your point of view, do you believe that music is about reproducing the stuff on the CD in the most unchanged/undistorted way? Or do you believe that music is about enjoyment and if this means that you prefer it 'unnatural' due to some EQ, does this make you wrong? Is Bill wrong because he prefers apples or is Kate wrong because she prefers Oranges?
 
I noticed the blobs too, looks like handiwork to me and not like it's been reflowed.
Perhaps the pics are of a prototype or a small pre-production series.

Unless the pic on his website under "Background information->Manufacturing and testing the mini dac" is just for show, it looks like a professional environment. The ESD mat on the table and the white coat are some of the signs. The mention of an "anti static zone" (we'd call it ESD Protected Area) also doesn't hint at it being made in a shed. Don't think they're using an Audio Precision, though...

yeah, even though i'm not convinced of the topology/methodology of the dac, i'm not suggesting he's less than professional at what he does best, but lets just say that isnt hand soldering. Prototype or not I sure wouldnt be letting that be the only really high quality photograph of the innards; any number of hobbyists here including myself and probably even some school kids these days can do much better and it was the first thing that struck my eye.
 
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I completely agree with 5th element's reasoning behind the incredibly subjective nature of human beings and the way that affects the way individuals all hear their own way. I also completely agree with the fact that knowing certain details before even hearing an audio device will lead to a highly biased choice in the end. No doubt my perception of the sound of the Octave was influenced by my opinions towards NOS.

Really, the only objective way to choosing the right piece of equipment subjectively is to do a double blind test of "black boxes". I.e. not knowing brand/type, technologies used, or even the number of contenders that are auditioned. This way there's only the sound to focus on, in the end it's the sound that matters.
I expect that, except for a handful of exceptionally adept people, this way most will actually get the number of auditioned devices wrong.
 
The FACT is that 16 bit 44.1kHz NOS filterless is horrible.
CD reproduction was never ment to be NOS. Using a 24 bit 192kHz signal is equal to a very good 4x OS applied to the CD (better than what a DAC can OS from 44.1). And as you could see, at that sample rate, the filtering requirements are way lessend.

CD never ment to be NOS? I'm not sure. If it had been up to Philips, the CD standard would have been 14 bit, and they designed their first DAC for that (TDA1540). Along came Sony and pushed for 16 bit.
The TDA1540 was already in production and a true 16 bit DAC wouldn't be ready in time for the launch of the CD-player in 1982.
Philips' engineers came up with a digital filter that combined 4x OS with a digital feedback loop that we would now call noise shaping to get 16 bits resolution from a 14 bit DAC. Later came the famous 16 bit TDA1541, but the idea of low bit conversion with 16 bit resolution (Bitstream) had already been born out of necessity.

I wonder if, without this change to 16 bit, the first DACs wouldn't simply have been NOS with an analogue brick wall filter.

PS: I don't know if you have the capability (good ADC) to make some measurements on your new NOS filterless (is that true filterless?) DAC and post them here - I would definitelly trust them more than a typed poem.

Well, I have a 16 MHz PC oscilloscope with FFT, so I should be able to do some measurements.

The article that first got me interested in NOS, many years ago, is here. It's a bit strange to read it as it seems to be made up of some glued together parts from a bigger whole, but the relevant parts are there.
 
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CD never ment to be NOS? I'm not sure. If it had been up to Philips, the CD standard would have been 14bit...

Not to mention that CD also was supposed to be perfect sound forever. Remember that particular bit of nonsense?

The article that first got me interested in NOS, many years ago, is here. It's a bit strange to read it as it seems to be made up of some glued together parts from a bigger whole, but the relevant parts are there.

Trust your own ears. No one listens to music through a spectrum analyzer. Which is to be preferred, a DAC which measures good on spectrum analyzer, yet fatigues your ears or disinterests you in your music collection (the ultimate sin for a HiFi system), or a DAC which doesn't measure as well, yet is a joy to listen to every day? The NOS DAC issues really is that simple, IMO. Continue to point out that you can see that the brickwall filtered CD emperor has no clothes.
 
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