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D100 disappointments

Don't get me wrong I am not claiming that I can hear a difference between USB cables per se. I am stating that a difference can be heard between usb cables with power lines activated and those with power lines inactive.

As for the above descriptions on how usb cables work, that seems to be in line with my understanding. I am, however, confused on one point. Some have stated that if the information packet is corupt, the dac will 'notify' the transmitter and the transmitter will then resubmit the 'packet'. What happens to the music at this point? The music has to continue and if the 'packet' is corupt, it is my understanding that the dac will drop that packet leaving a whole in the data. Waiting for the packet to be delivered a second time will surely interfere the pace of the music. No?

Also, it is my understanding that every dac handles variations in the voltage differently. I.E. if 0V represents a 0 and .5V represents a 1, what happens if interference on the data line causes the voltage to be .25V, for example. Or .35V. What the DAC does with that can vary between dacs resulting in a difference in sound caused by 'dropped packets'. i don't think this is a huge problem but I do think that the insulation the usb cable has, can help maintain a more precise voltage as the electrical signal makes it's way to the dac.

Has anybody tried my experiment of covering pin 1? I am curious if anyone else has noticed such an extreme difference -- of course you do need a d100 for this, as most dacs require the power line to function.
 
ehborden said:
As for the above descriptions on how usb cables work, that seems to be in line with my understanding. I am, however, confused on one point. Some have stated that if the information packet is corupt, the dac will 'notify' the transmitter and the transmitter will then resubmit the 'packet'. What happens to the music at this point? The music has to continue and if the 'packet' is corupt, it is my understanding that the dac will drop that packet leaving a whole in the data. Waiting for the packet to be delivered a second time will surely interfere the pace of the music. No?

Also, it is my understanding that every dac handles variations in the voltage differently. I.E. if 0V represents a 0 and .5V represents a 1, what happens if interference on the data line causes the voltage to be .25V, for example. Or .35V. What the DAC does with that can vary between dacs resulting in a difference in sound caused by 'dropped packets'. i don't think this is a huge problem but I do think that the insulation the usb cable has, can help maintain a more precise voltage as the electrical signal makes it's way to the dac.
Click to expand...
Data received from USB communication will be placed into memory. The DAC reads from that memory. It's not waiting on every single byte to come over the port. Similar to when you burn a CDR, the CDR isn't writing from your hard drive, it's writing from its buffer that was filled with data from your hard drive.

Any properly shielded cable will work fine, again unless the cable has been damaged. The USB 3.0 specification has even greater protection against EMI.
 
If you are getting noise with the power feed enabled than something is either wrong with the cable or the equipment. It shouldn't be inducing any audio qualities in a properly designed and filtered circuit.

One thing I have seen is when you have a ground loop issue noise might occur over a USB connection. I had this happen once when my laptop was suffering from a ground loop and was introducing noise to my external DAC. Once I solved the problem the noise went away.
 
smartin53 said:
If you are getting noise with the power feed enabled than something is either wrong with the cable or the equipment. It shouldn't be inducing any audio qualities in a properly designed and filtered circuit.

One thing I have seen is when you have a ground loop issue noise might occur over a USB connection. I had this happen once when my laptop was suffering from a ground loop and was introducing noise to my external DAC. Once I solved the problem the noise went away.
Click to expand...

It is possible that the d100 is "improperly designed" -- I think it is one badass dac.
 
Whenever you are connecting a noisy computer to a DAC there is the possibility of noise travelling down e.g. the USB cable. The wave file is still transferred bit-perfectly, however there is common mode noise that is also travelling down the same cable which to some is noticeable as e.g. listening fatigue, shrinking of soundstage or a raised noise floor.

A relatively cost effective way is the IFI USB Power, which provides a cleaner 5V and a switch to break the ground in the USB connection. This might help.

I have not heard a better USB connection to a DAC than the Berkeley Audio USB magic box via XLR, but it is not cheap. This has improved the audio not only in the D100, but in every USB DAC I have tried including $10K+ DACs.

And you can even use both those tools together, and the files will still transfer bit perfectly, but common mode noise is reduced quite a bit.

If your USB cable is not shielded it could also pick up RFI and EMI from the surroundings, which could even come from an HDMI cable, or a power cable that is too close to the USB cable. A shielded cable does not have to be an expensive one by the way, just well constructed. I use a cheap $10 shielded USB cable.

Make sure you put a little distance in between the cables as well. This is one of the cheapest and effective tweaks. Same thing counts especially for the analog RCA cables by the way. Something to try first, and it is free!

For what it is worth, the fixed outputs on the D100 sounded better to me than the variable ones.

Cheers.
 
McIntosh does not use the 5V pin on any model that has USB audio input. The 5v power supply from a computer is a poor choice for a DAC as the decoders must have a completely stable voltage to produce maximum performance.

Thanks,
Ron-C
 
I migrated from a USB to DAC to an Optical to DAC and I'll never go back. Many new motherboards have numerous digital connection options.
 
I use optical from D100 to MCD301 with excellent results (~MCD1100). I use USB from D100 to Mac with same excellent results. Dead silent either way.
 
toslink vs usb

I've done this comparison a hundred times and I was unable to notice any difference in the two inputs until I disabled the 5V pin. Once disabled the USB is noticeably better. Plus USB allows for use of higher resolution files and 32 bit resolution which comes in handy for DSD conversion.
 
ehborden said:
I've done this comparison a hundred times and I was unable to notice any difference in the two inputs until I disabled the 5V pin. Once disabled the USB is noticeably better. Plus USB allows for use of higher resolution files and 32 bit resolution which comes in handy for DSD conversion.
Click to expand...

That's interesting considering the 5V pin is not even used or connected in the D100......

I think you might be imagining things....but hey, I'm not there and listening.....But in this case there is complete science to support the theory it wont affect anything insulating the 5V pin.....
 
damacman said:
I migrated from a USB to DAC to an Optical to DAC and I'll never go back. Many new motherboards have numerous digital connection options.
Click to expand...

My Benchmark DAC1 has optical, spidif, USB and analogue....the whole kit and kaboodle...
I actually use all of them except the analouge in...

TV= Optical
Computer= USB
CD player= spidif...

There isn't any noticeable difference between the various analogue options.....they are all brilliant...
 
ehborden said:
Lol. Pretty sure it's connected, the d100 is not completely isolated from it. And it's use is to transmit noise.
Click to expand...

Well the guy who works for McIntosh says its not....so yeah well.....have fun...

As long as you are happy then its all good.......Im listening to my Benchmark via USB......just stunning.....
 
kevzep said:
Well the guy who works for McIntosh says its not....so yeah well.....have fun...

As long as you are happy then its all good.......Im listening to my Benchmark via USB......just stunning.....
Click to expand...

cmon now. Ron said that no mcintosh dacs make use of the 5v feed. He didn't say that the 5v feed wasn't making use of the dacs. How does the d100 isolate itself from that dirty dirty feed? I can clearly hear that it doesn't. And so could you, if you even tried.
 
ehborden said:
cmon now. Ron said that no mcintosh dacs make use of the 5v feed. He didn't say that the 5v feed wasn't making use of the dacs. How does the d100 isolate itself from that dirty dirty feed? I can clearly hear that it doesn't. And so could you, if you even tried.
Click to expand...

my system doesn't have any noise.....there's nothing to improve....Not trying to be argumentative, but there's no improvement to make so why would I try it...Just sayin...

But I am talking about a Benchmark DAC1 so its apples and oranges in any case.....
As I said, as long as you are enjoying the fruits of your tweaking, then all good....
 
The 5V pin on all McIntosh USB inputs is not connected to anything inside the Mcmachine. That pretty much isolates it.

Thanks,
Ron-C
 
ron-c said:
The 5V pin on all McIntosh USB inputs is not connected to anything inside the Mcmachine. That pretty much isolates it.

Thanks,
Ron-C
Click to expand...

exactly, that's what I thought you said.......

I think there's something in the imagination going on here, or there is a problem with the the computer of whatever the music source is....
 
ron-c said:
The 5V pin on all McIntosh USB inputs is not connected to anything inside the Mcmachine. That pretty much isolates it.

Thanks,
Ron-C
Click to expand...

Not quite. There is also a ground pin on the USB which will happily transfer common mode noise.

On the IFI USB power and other similar gadgets there is a switch which will allow you to cut the USB ground.
 
kevzep said:
exactly, that's what I thought you said.......

I think there's something in the imagination going on here, or there is a problem with the the computer of whatever the music source is....
Click to expand...

No imagination. And it is not necessarily a problem with the computer, as it is inherently noisy. Switching power supplies, constant changes of draws of power from elements that are installed such as hard drives, fans, antennae (bluetooth, IR, wireless) all impact quality of sound. And no I don't mean it changes the bits in the music file, but it adds common mode noise that will happily flow downstream.

Here is a nice video showing common mode noise impact that is measurable using an oscilloscope.

http://m.youtube.com/watch?v=BFLZm4LbzQU&desktop_uri=/watch?v=BFLZm4LbzQU
 
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