advertisement


MDAC First Listen (Part 00101001)

Status
Not open for further replies.
clivem2 said:
Assuming sonic differences are down to RF getting into the DAC then eye pattern analysis will only be a side issue. We need Detox with associated tests. I'd ignore the HFN article.
Click to expand...

Let's assume nothing, let's have some double blinded tests to show it makes any difference before going any further. I agree with you on ignoring the article.
 
That's because the mdac has bugger all filtering on the USB input, its very poor in that respect. Any xmos equipped dac clearly shows it up in this respect.
 
JohnW said:
Typically RF tends to harden the sound and add a "Glassy" sharpness and sibilance which we tend to associate these "signatures" as sounding "Digital".

The lower Jitter tends to widened the Left / Right sound stage while firming up the systems low end, but how USB Frame packet jitter impacts the sound is very dependent on the System / DAC.

What the Detox will do remains to be "heard" :) But at least I can be sure we have given the MDAC / FDAC the best quality USB signal - and in the case of the MDAC, a galvanically isolated USB port.

The USB 1.1 port with its galvanic isolation will reduce "background" noise and hum loops if present in the system when connected to the PC or when the Laptop is connected to its AC mains adaptor.

I believe that when the Spread spectrum decorrelator mode is enabled the system will lose an extra layer of hardness and sound more "Organic / Analogue".

Sorry if this sounds very vague and "HiFi babel" - but when you hear the effect for yourself then you will understand what I'm trying to describe.
Click to expand...

John

I am using a Vortexbox connected directly to a MDAC via a USB cable. The Vortexbox is basically a headless computer so I assume it is likely to benefit from one of these recently developed gizmos in the form of a Jitterbug, Decrapifier, ReGen or your own proposed Detox units?

There are various reviews available for the Jitterbug, Decrapifier and ReGen promoting the benefits of these devices some claiming that using both the Jitterbug and Regen together can yield further improvements http://www.audiostream.com/content/...est-jitterbug-schiit-wyrd#hLzkTOrXbxqmIHdK.97.

You are proposing your own Detox unit, is it expected to provide the same benefits that seem to be achieved with the current crop of devices or will that only be known once it has been designed, built and tested/evaluated? Is the proposed design of your Detox unit expected to provided the combined benefits of both the Jitterbug and ReGen in one unit? Are there other improvements/benefits that you feel your Detox unit will have/bring?
 
I don't hear any benefit from the free version of Fidelizer any more, or from unplugging the smps from the laptop. If (hopefully) the FDAC pushes the 'diminishing returns' boundary further away, I'll have to re-consider the software and hardware options.
The process is decidedly addictive.
 
jkeny said:
Is the article only in print or can you post the eye diagrams- what is the x-axis (time) scale?
Click to expand...

AADeoSKrxelIeaQIZEaPCbtCa


The one below is with the jitterbug. I understand how in principle the measurement could be misleading depending on the roundness of the corner- but here, seriously? 33% reduction in rise time? wtf?
 
John
Active crossover related question; What do you anticipate will be the voltage gain of the VFET amps, 26db?

Also did you miss my question at post no 385?
 
I'm just amazed that DACs with USB inputs have been out for years (>10years?) from 10's of manufacterers and only very recently have any of them considered noise entering their DACs via the USB port....why don't DAC makers licence these USB hub gizsmos and put them inside their DACs?....maybe nobody looked upstream of their designs or is that users will buy/try anything that's promoted in a certain way....its like alternative health therapies... we are all desperately seeking SQ improvements however small (or non-existant) and so open to exploitation?
Still...it's all good fun and interesting!
 
timola said:
I'm just amazed that DACs with USB inputs have been out for years (>10years?) from 10's of manufacterers and only very recently have any of them considered noise entering their DACs via the USB port....why don't DAC makers licence these USB hub gizsmos and put them inside their DACs?....maybe nobody looked upstream of their designs or is that users will buy/try anything that's promoted in a certain way....its like alternative health therapies... we are all desperately seeking SQ improvements however small (or non-existant) and so open to exploitation?
Still...it's all good fun and interesting!
Click to expand...

Good engineers realised this years ago, and designed proper isolation, unfortunately not all.
Keith.
 
I would have thought of all people you would recognise a good design, after all you purport to be a dac designer.
Keith.
 
davidjt said:
One of yours, perhaps?
Click to expand...

Nope! As JohnW has said galvanic isolation at HS USB speeds is not currently feasible as a technology for inclusion inside a DAC. All claims of galvanic isolation that I've seen mean that they have opto or GMR isolators on I2S signal lines downstream of the USB receiver chips - this is too late in the chain - the damage is already done.

edit: deleted info about my digital audio devices as this is the MDAC thread
 
Purite Audio said:
I would have thought of all people you would recognise a good design, after all you purport to be a dac designer.
Keith.
Click to expand...
You are admitting that you have not got a clue about what you are stating/claiming - just another of your throw-away lines. If not, then name a DAC with "proper isolation"
 
Define proper isolation?


I'll take a GMR over sweet F A, which is what the mdac has. The xmos i2s devices seem to make a great job of it, the difference between mdac noise and young dac was chalk and cheese.
 
sq225917 said:
Define proper isolation?
Click to expand...
Yes let's hear Keith's definition of the phrase "properly isolated" he used


I'll take a GMR over sweet F A, which is what the mdac has. The xmos i2s devices seem to make a great job of it, the difference between mdac noise and young dac was chalk and cheese.
Click to expand...
You've mentioned XMOS & isolation twice now - what exactly is in the XMOS technology that confers any isolation, do you think?
 
davidjt said:
I am currently using a Jitterbug on one end and a Regen on the other. The fact that both have a positive effect suggests that John's 3-stage solution will be better still......
Click to expand...

Can anyone give me some word's on that 3 stage solution
Thank you ;-)
 
Status
Not open for further replies.


advertisement


Back
Top