[Denys]

Quote:

guys!
getting a USB-isolator for DI us a MUST
it clears sound really nice, making it even more transparent

May I please ask what's a USB isolator ?
 
Denys
 
 

 

[kr0gg]

it's a device that connects between your PC's USB port and any USB device. this isolator electrically decouples them and eliminates unwanted electrical hum coming from dirty PC' power lines.
there's a variety of those, after some searches i've bought this one:
http://www.olimex.com/dev/usb-iso.html
 
these guys have a representative in US and for some reason it costs there even cheaper than originally in Europe
 
there's a guy named "leeperry" here that bought a bunch of different usb-isolators and compared them. you can search for his impressions

 

[Denys]

 
Quote:

it's a device that connects between your PC's USB port and any USB device. this isolator electrically decouples them and eliminates unwanted electrical hum coming from dirty PC' power lines.
there's a variety of those, after some searches i've bought this one:
http://www.olimex.com/dev/usb-iso.html
 
these guys have a representative in US and for some reason it costs there even cheaper than originally in Europe
 
there's a guy named "leeperry" here that bought a bunch of different usb-isolators and compared them. you can search for his impressions

It's not so expensive.....they have a representative in Canada.....they don't seem to have it in stock but I could ask them if they could have it...
 
I could use it with my coming NFB8... I did not order a DI.... The one I have, I use it with my REF5...
 
Thanks for the tip anyway...
 
Denys
 
 

 

[Eunegis]

Quote:

nay. don't have this kind of money
i was thinking about learning Linux and building a separate HTPC or buying a notebook for playing music/movies. (my main PC produces TONS of noises)

My warm suggestion:
 
don't do it in Linux (though I like it, too) - build up a cMP²-System instead! (= "cics memory player" PC)
That's a very well proven and well documented system that can be realized for a reasonable amount of money.
You can vary the plans to your needs, technically and optically. Many different options are available.
 
Take a look at http://www.cicsmemoryplayer.com/ and use it as a source of inspiration!
You'll find a good starting point on that page, but you don't need to stick slavishly to it.
 
Further sources of information and inspiration are
http://www.audioasylum.com/cgi/etv.mpl?forum=pcaudio (the basic forum), and as parts of that:
http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=27041 (comprehensive!) and
http://www.audioasylum.com/cgi/vt.mpl?f=pcaudio&m=31286 (comprehensive as well).
 
Its truly worthwile. You'll learn a lot and have much fun with it (as long as you feel a slight affinity to PCs).

 

[Denys]

 
Quote:

it's a device that connects between your PC's USB port and any USB device. this isolator electrically decouples them and eliminates unwanted electrical hum coming from dirty PC' power lines.
there's a variety of those, after some searches i've bought this one:
http://www.olimex.com/dev/usb-iso.html
 
these guys have a representative in US and for some reason it costs there even cheaper than originally in Europe
 
there's a guy named "leeperry" here that bought a bunch of different usb-isolators and compared them. you can search for his impressions

I just spoke to the rep here in Montreal... He'll verify if he has any in stock and how much it costs... We'll take it from there...
 
Denys
 
 

 

[somestranger26]

Here's a link I found to leeperry's comparison of a couple different USB isolators: http://www.head-fi.org/forum/thread/496735/firestone-bravo-24-96-usb-transport-w-o-drivers-reclocker/300#post_7126768 he seems to prefer the Aimagin one to the USB2ISO. I'm thinking about getting one.

 

[kr0gg]

well, from my point of view... speaking of a dongle which costs almost $100 shipped and one for $50...there's too much price difference than possible SQ difference.
i've bought DI from Audio-gd for $145 shipped, its original PSU here in FS forum for $50 shipped. paying half of their price seems kind of unrational to me.
 
oh, and by the way - the USB2ISO that he speaks of in that post is not the Olimex one that i speak about. he bought the Olimex one only later and from my memory - actually preferred it over all other dongles

 

[somestranger26]

I read a few more pages and indeed it appears he likes the Olimex the best and it's cheapest. Found some in the U.S. for $41 shipped here http://microcontrollershop.com/product_info.php?products_id=3769 pretty good price.

 

[uelover]

Hmm what use is a USB isolator if we are using an external power to power our DI instead of drawing the current from the USB port?
 
Seems like there is the USB DC power option too.

 

[Denys]

Quote:

Hmm what use is a USB isolator if we are using an external power to power our DI instead of drawing the current from the USB port?
 
Seems like there is the USB DC power option too.

Well, I did not order a DI with my NFB-8 that I'll get in a few weeks. The CAD rep sells me a USB isolator for less than $50 CAD.... I'll give it a try.....I find the risk is minimal...
 
Denys
 

 

[uelover]

Quote:

Well, I did not order a DI with my NFB-8 that I'll get in a few weeks. The CAD rep sells me a USB isolator for less than $50 CAD.... I'll give it a try.....I find the risk is minimal...
 
Denys

Yeah your case I can understand, as with any other people who use direct USB connection for their DAC.
 
I am just curious about the need for one when using a DAC with the DI (with PSU).
 

 

[kr0gg]

Quote:

Hmm what use is a USB isolator if we are using an external power to power our DI instead of drawing the current from the USB port?
 
Seems like there is the USB DC power option too.

its not about feeding it with power from PC.
the problem is that even with external PSU there is electrical contact with PC through the USB cable which transmits noises.
you can check it like this: disconnect your DI from PC, keep your DAC and AMP turned on. now turn the AMP volume to the max and after that connect your DI the way it is supposed to work. you will hear that with DI in chain there will be new noises.
you might think that if those noises are audible only on extreme amping levels (which noone uses in real life), then that is not a problem.
well, i should say that it actually is and an isolator makes audible difference on usual listening levels

 

[uelover]

Quote:

its not about feeding it with power from PC.
the problem is that even with external PSU there is electrical contact with PC through the USB cable which transmits noises.
you can check it like this: disconnect your DI from PC, keep your DAC and AMP turned on. now turn the AMP volume to the max and after that connect your DI the way it is supposed to work. you will hear that with DI in chain there will be new noises.
you might think that if those noises are audible only on extreme amping levels (which noone uses in real life), then that is not a problem.
well, i should say that it actually is and an isolator makes audible difference on usual listening levels

I have tried the above-mentioned.
 
I seriously hear nothing. No noise nor whatsoever with all volume pot maxed out.
 
Seems like you have got a 'dirty' USB port.

 

[kr0gg]

Quote:

 
Seems like you have got a 'dirty' USB port.

the problem might be in the fact that most of buildings (and the one where i live) don't have electrical grounding. but it's not a problem anymore.
at least for my USB connection

 

[wushuliu]

Quote:

You may want to keep the new chip in longer to let it "burn-in" a bit. My replacement TI 74AHC04 made the DI sounded very harsh like you mentioned at the beginning, it "settled down" after 10 hours or so. I found the improvements brought by the TI chip is at the bass frequency region, with a lot more textures and dimensions.
 
For your information: Depending on the operation temperature and voltage, the DI's stock 74HC4 chip would have 15-25ns signal propagation delay going from low (0)to high (1), the 74VHC variant chips give 2.5ns to 8ns delay. The highly praised Audiophileo 1 USB-SPDIF converter default delay is at 700ps (0.7ns) and allow the user to tune for longer delay. The Audiophileo 2 fixes it at 700ps.
 
Usually the shorter the delay, the better it will sound. But other value "could" sound better depending on coaxle cable length the amount of signal reflection.
 

Yes, I take back my thoughts on it. There were some gear changes that may have been the cause; once I got those sorted out and tried the AHC again, the hardness was gone.