Directream with mutec mc-3+


#1

Greetings. I would like to know with someone tried this product called mutec mc-3 with DirectStream . Thanks


#2

There was a discussion about the use of this sort of device with DirectStream a while ago. From what I recall, Ted Smith explained a technical reason why you are better off using the internal clocking of the DS.


#3

From reading the description on their site: if you used the device to generate a clock at a rate that isn’t locked to the input (which I infer they don’t since they talk about clock generation at various specific frequencies) then you are forced to resample the input with a different clock than the input has - that’s Asynchronous Sample Rate Conversion (ASRC). ASRC does indeed allow the output clock to be as clean as the box can generate, but encodes the incoming jitter into the data permanently so that it can’t be removed downstream. To see that it has to, suppose the incoming rate is high or low by say 100ppm (that’s perfectly in spec for AES3, S/PDIF or TOSLink). then you are getting 100 parts per million ahead or behind the incoming data each second. If your nominal sample rate is 352.8k then every second you get ahead or behind 35 samples. To avoid dropping those extra samples or repeating some samples all of the incoming data needs to be changed to preserve the information…

Some prefer the sound of ASRC and that’s a personal choice which I have no problem with.

FWIW tho they compare themselves to older digital technology that had spurs and other frequency distortions, they seem to still be using digital technology to generate their clocks (which still has jitter, but it’s ameliorated by using sigma delta modulation to smooth it out.) The DS avoids all of this by using analog control of a very low phase noise crystal to generate the local clock and it follows the average of the incoming sample rate so it doesn’t need to alter the data to keep in sync.

I’m not saying you won’t like the change reclocking upstream of the DS - but most won’t. The real difference (when going to the DS) will be the new groundloops in your system with more connections, the shielding of the links to the DS and your source, etc. and (when talking to the DS) that will swamp the differences that the technology is specifically designed to handle. I.e. you won’t be modifying your system in the most cost effective way.


#4

Thank you very much! I really didn’t expect that Mr Smith himself would answer me.

Just felt a joy to have the ps audio DSD in my house. I will direct my money to other products like the briedge 2 and forget the mutec.


#5

I use a Mutec and I am very happy with it. I use the Mutec 1.2, the smaller version of what you are considering. It passes bit-for-bit and exactly the same word size and clock rate. It passes both PS Audio bit-for-bit test files fine and unit displays the “B” in the upper right had corner. It is as if it is not there.

A thread here where I discussed my use of Mutec: New DS owner, share your experience of the dac running in from new?

I hook it up to my PC-USB-Mutec-XLR-DirectStream Junior. I have compared this hookup to my PC-USB-DirectStream and I can not hear a difference. The display on the DirectStream shows the exact same information (rate/bit) etc. regardless if the Mutec is in the chain or not.

The reason I have the Mutec is simply for convenience. I had the Mutec prior to the direct stream because I needed a USB interface and a re-clocking unit between my PC and my Accuphase CD Player (has digital ins). The Accuphase is really suseptible to jittre hence the desire for this Mutic unit. Now with the DirecStream, I don’t need it but, it allows me to hook up three DACs at once for cool A/B/C comparisons since the Mutec presents a bunch of live digitial outs. So I can then hook up each DAC to it, and then from each DAC, I go to my integrated amp where I can simply switch between them while they are all playing the exact same source stream… cool.

Said again, I find the Mutec 1.2 a very handy device that has no down side at all that I am aware of either in sound or functionality from my DirectSTream.

Peace
Bruce in Philly
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#6

So Ted, you have me paranoid now… so I am going to go home tonight and do some more analytics on the sound with the Mutec in the chain. But honestly, I could not tell the difference with my prior experiments.

Here is a direct link to the mc-1.2 technical description… sounds good to me, but what do I know? https://mutec-net.com/product_mc-12.php#description

Peace
Bruce in Philly


#7

With USB the receiver can control the speed of the incoming data and hence can be the master of the clock rates and doesn’t need ASRC (on the other hand the DS assumes it’s the master when using USB so I’m not sure what the mutec is theoretically adding.) With AES/EBU (AES3), S/PDIF, TOSLink the source controls the clock rate and ASRC is necessary if you are also syncing to another clock. I2S technically supports having the master clock coming from either end, but that’s not typically supported by all hardware.

Still it looks like the mc-1.2 and mc-3 do different things - the mc-1.2 fans USB out to multiple outputs, the mc-1.3 is a “master clock” - it’s being a master clock and accepting AES/EBU, S/PDIF and TOSLink as inputs that’s impossible without something like ASRC. As mentioned above the problem with USB in this situation (which supports either end being a master clock) is that the DS then assumes it’s the master, so in no case can the mc-1.3 be the master clock unless it uses ASRC.


#8

OK, this Mutec 1.2 is sounding better… What it added for me with my PC to Accuphase, was two things: a USB interface to the computer and jitter removal (or reduction) to the Accuphase DAC. I spoke to Accuphase many years ago and given this was an early unit with a digital IN, they did not buffer/reclock the incoming signal… the unit just ate whatever jitter it received. This Mutec gave me a vast improvement in sound quality. (Years ago I used an Audio Alchemy device to do the same).

So now, with the Junior, the only thing the Mutec 1.2 adds is the fanning out to other output interfaces… Your Junior deals with the the jitter from a direct USB-computer link so no need for the Mutec. I keep the Mutec in the system because of the entertainment value of A/B/C’ing my various DACs. Oh, and the Mutec driver has a Windows pop up that will denote connectivity status and format.

Thanx again, Ted,

Peace
Bruce in Philly