Metrum Acoustics Octave

[gregorio]

For myself, I'd like to seem how it measures, if it has aliasing issues for example.

It's possible to have some imaging (aliasing) issues with a poorly implemented reconstruction filter but without a reconstruction filter at all, imaging (aliasing) issues are guaranteed! How badly the imaging issues will affect what you are listening to will depend on the music you are playing, the quality of your speakers/headphones and of course your hearing ability.

G

 

[bobeau]

 
Quote:

It's possible to have some imaging (aliasing) issues with a poorly implemented reconstruction filter but without a reconstruction filter at all, imaging (aliasing) issues are guaranteed! How badly the imaging issues will affect what you are listening to will depend on the music you are playing, the quality of your speakers/headphones and of course your hearing ability.

G

I had an Anedio D1 for a month.  It came with plots showing how well it tested on a bench. 
 
To my ears it sounded brittle and overly digital.  Tried a Minimax as well.  So two DACs using what is arguably the top delta-sigma chip around, filtering and jitter busting up the wazoo.  I did not like. 
 
Went back to an Ack Dack 2.0, a NOS TDA1545.  As far as this class of old school DAC chip is concerned this is not supposed to be remarkable, but I prefer it.  It sounds closer to what I consider reality.
 
Apparently my hearing ability is total schitt, and as such I will stay with NOS world, just looking for the next level up.  So there you go.
 

 

[gregorio]

Went back to an Ack Dack 2.0, a NOS TDA1545.  As far as this class of old school DAC chip is concerned this is not supposed to be remarkable, but I prefer it.
 
Apparently my hearing ability is total schitt, and as such I will stay with NOS world, just looking for the next level up.  So there you go.
 

What you like listening to is entirely up to you, I'm not telling you what you should like. A lot of people prefer vinyl, even though it is inferior as a format in every way to CD. This is even more the case with filter-less DACs, which by definition are highly inaccurate as they do not conform to the basic rules of digital audio. But if you like listening to distortion and somehow feel that it gets you closer to reality, that is entirely your choice and prerogative.

Whatever your personal preferences, the fact is that not having a reconstruction filter will cause imaging issues.

G

 

[bobeau]

Quote:

One my friend would like to order one. He wrote them two emails and did not get reply. What is your experience guys? He want order via bank transfer because he do not have paypal at this moment.

I sent one email, 24 hours later I hadn't gotten a response so sent another and got a response within an hour - which was letting me know there was an 8-10 week lead time, and if I agreed an invoice would be sent.  I agreed and an invoice was sent as a PDF a few hours later.  Paid with Paypal (I'm in US so that's my only option) and got a confirmation email shortly after. 
 
It seems like a pretty small operation (all communication was with the owner, Cees) and they might be even more thoroughly swamped now that initial user impressions are out - there's now 3 people in that Aussie thread, pretty well known guys in the community that compared against other DACs in their stable and are gushing over it.
 

 

[bobeau]

Quote:

 the fact is that not having a reconstruction filter will cause imaging issues.

G

Thank you for your valuable contribution.  My ears will take your facts into consideration.
 

 

[gregorio]

Thank you for your valuable contribution.  My ears will take your facts into consideration.
 

They are not my facts, they are the facts of digital audio. And apparently your ears are incapable of taking facts into consideration.

G

 

[khaos974]

For myself, I'd like to seem how it measures, if it has aliasing issues for example.

It's possible to have some imaging (aliasing) issues with a poorly implemented reconstruction filter but without a reconstruction filter at all, imaging (aliasing) issues are guaranteed! How badly the imaging issues will affect what you are listening to will depend on the music you are playing, the quality of your speakers/headphones and of course your hearing ability.

G

Does aliasing occur with R2R DACs or is it a limitations of sigma delta architectures?

 

[K3cT]

Quote:

And you know this how?  Most likely it's other boutique makers to be worried about.  He can't hide the circuit, which is simple and easy to copy, but his work selecting a chip not intended for this domain is a unique competitive advantage. 
 
You could be right, it could be a total BS marketing move and it is indeed a common audio DAC chip.  But if it's not I don't see exactly what the problem is, IP is IP.
 

Or they could have "copied" the poor Japanese guy's design and profit from it. It's not like this is the first time it's happening either in the DIY community. 

 

[gregorio]

Does aliasing occur with R2R DACs or is it a limitations of sigma delta architectures?

The Nyquist-Shannon Theorem requires that all frequencies above half the sampling rate be removed. This is the purpose of the reconstruction filter. Another way to think about it is that the digital data on your CD (or SACD or 24/96, etc.) contains the original signal plus an error signal, the error signal entirely exists above the halfway point of the sample rate (the Nyquist point). The anti-imaging filter removes all the frequencies above the Nyquist point and hence the error signal.

Any DAC with a well implemented anti-imaging filter should not exhibit any imaging artefacts. Although it is impossible to implement a good anti-imaging filter on files higher than 24/96. So whether or not any DAC exhibits imaging issues depends entirely on it's filter design. In general though, you would not expect to see any imaging issues in any reasonable quality DAC (providing you are playing files of 24/96 or lower).

G

 

[songmic]

In Korea the U3 is 450,000 KRW, which is approximately $400 in USD.
I've had the hiFace too, but sold it away once I realized the U3 was much better.

 

[songmic]

 
Quote:

Out of curiosity, how much is the U3 in USD in Korea?

 
In Korea the U3 costs 450,000 KRW, which is approximately $400 in USD.
I've had the hiFace too, but sold it away once I realized the U3 was much better.

 

[gurus]

Quote:

 

I had an Anedio D1 for a month.  It came with plots showing how well it tested on a bench. 
 
To my ears it sounded brittle and overly digital.  Tried a Minimax as well.  So two DACs using what is arguably the top delta-sigma chip around, filtering and jitter busting up the wazoo.  I did not like. 
 
Went back to an Ack Dack 2.0, a NOS TDA1545.  As far as this class of old school DAC chip is concerned this is not supposed to be remarkable, but I prefer it.  It sounds closer to what I consider reality.
 
Apparently my hearing ability is total schitt, and as such I will stay with NOS world, just looking for the next level up.  So there you go.
 

I still enjoy my ancient Wadia 2000. I just could not get myself to get a newer DAC for my speaker system over all these years. Maybe because the Wadia totally sounds like the Vinyl sound I so loved without the hiss crackle and pop. After all I was coming from a Linn/Breuer/Koetsu combo. As far as DAC measurements and sound  correlation is concerned here is an old article that might be of  interest.
 
http://www.stereophile.com/content/wadia-2000-decoding-computer-measurements
 
 

 

[gregorio]

As far as DAC measurements and sound  correlation is concerned here is an old article that might be of  interest.
 
http://www.stereophile.com/content/wadia-2000-decoding-computer-measurements

Thanks. I'm not sure that article tells us any thing we didn't already know. That where measurements and a professionally trained and unbiased ear detect significant distortion, some audiophiles (and particularly audiophile reviewers) will instead hear "depth, detail, nuance and resolution".

G

 

[bobeau]

From the Aussie thread:
 
"The Metrum is back at Casa Kdoot for the weekend. I had to have another listen because I couldn't quite believe my own reaction from earlier in the week. Surely it couldn't be as good as my first impression and write-up made it out to be.

I have listened to a lot of DACs in the past year and a half, and while some of them have been especially good (Level 2 PDX with internal JK HiFace is wonderful, Audio-GD Reference 7 is a standout over-engineered solid-state performer) none of them have had the same kind of utterly compelling effect on me that the Octave has. I used to play a few different instruments and perform a lot of music in my youth, and music has always been something that I've felt more than thought about. The Octave is doing something so uniquely right as it turns these bits into waves that the music just takes over. My foot taps, my head sways, and the performance is everything. No other DAC has done that for me.

I don't give a **** what this thing has inside it. It's made of magic as far as I'm concerned.

Order placed."

 

[bobeau]

Quote:

I still enjoy my ancient Wadia 2000. I just could not get myself to get a newer DAC for my speaker system over all these years. Maybe because the Wadia totally sounds like the Vinyl sound I so loved without the hiss crackle and pop. After all I was coming from a Linn/Breuer/Koetsu combo. As far as DAC measurements and sound  correlation is concerned here is an old article that might be of  interest.
 
http://www.stereophile.com/content/wadia-2000-decoding-computer-measurements

Thanks for that.  I'll definitely give it a read later today.  My experience is not huge, but I've owned I believe 6 outboard DACs since I got into this stuff about 7-8 years ago, and heard at least another dozen... including the venerable Benchmark DAC--1 which I thought was utterly unlistenable.  The two NOS DACs I've owned have been it for me.  I listen to headphones some 4-8 hours daily writing system software for medical inventory tracking systems.  I analyze enough stuff.  I don't want to be analyzing my music too, I'd rather forget I even have headphones on, am sitting in a cubicle in a huge office space with people moving around.  Getting there.