VDAC noise from Imac USB airport express ?

[admin_exported]

Hi I have a musical fidelity Vdac, which I am using with the following

Arcam CD73T Opto digital

Denon TU1800DAB tuner coax digital

Imac USB.

The problem I am getting is when the Imac is connected via USB I am getting some noise from the Imac / earth loop. I am using a 5 meter usb cable ( cheap cable, but it digital). Is there anything I can do to cut the noise, the DAC and all HIFI is plugged into a tacima mains filter. The Imac is not , but I am not sure that will help, I guess its from the Imac psu.

As I am not sure the dac improves the Arcam , I am think of using the Mac via my airport express into the Vdac opto, which will be ok.

Has anyone got any other Ideas ?

Thanks

 

[Anonymous]

Perhaps you can try to isolate the problem a bit further, to see if indeed the imac usb ground is causing the problem:

- Do you also get is with a short usb cable?

- Any difference if you remove the tacima filter?

 

[Anonymous]

HI I have tried that thanks, the noise was the same. I guess its the Imac PSU/fan. Will the quality be the same with the Airport express into the opto on the Vdac ?

thanks

 

[Craig M.]

if the vdac behaves with usb the same way my dacmagic does, i would expect the optical to be a slight improvement. this is without hum from either. i would not expect the hum you get with usb to be present with optical.

 

[Anonymous]

USB is a bad way to connect a computer to a hi-fi system.

Use an optical cable (which will also give you 24bit/96kHz abilities), or wireless.

 

[Anonymous]

Hi

I have a queation you may be able to answer.....i stream Spotify from my PC wirelessly (using Jamcast) to my PS3 and onto my Amp. Where does the D to A conversion happen? PC? PS3?

Cheers

 

[Anonymous]

wickerman68 its the ps3

jpfreestyler im using a macmini via optical into a vdac and its noise free which is what youd expect as optical cant cause an earth loop

the ae is a wireless device using optical to the vdac so it cant introduce hum either and the quality is the same as optical from the mac

id test with the optical cable which should be silent if the system still has earth hum then its another problem

id also disconnect the tuner to see if thats part of the problem

 

[Anonymous]

Cheers...I have a £4000 amp so should add a DAC?

 

[Anonymous]

ive heard the ps3 isnt so good so perhaps its an idea

what amp do you have it really depends on that

 

[Anonymous]

I have a Graaf GM50....reviewed on this site

 

[Anonymous]

yes definitely although spotify isnt the greatest source

id be looking at benchmark or the new naim dac as a minimum if you wanted to go down the streaming lossless files route also but if you only use spotify you could get away with a cheaper dac seems a waste of a good amp though

what is the rest of your setup out of curiosity

 

[Anonymous]

lector 7T CDP

Nordost SPM

Graaf

Audience AU24

Art Emotion Speakers

Spotify is just for fun not critical listening

 

[John Duncan]

wickerman68:Graaf

Spotify is just for fun not critical listening

Spotify can sound fantastic, but you most certainly need a DAC for that amp. A DACMagic has balanced outputs, which the Graaf can take, no? Whilst I would normally agree that you could be looking higher up the DAC scale with an amp like that, i think you'd be surprised at just how good the DM is, particularly if you use the balanced connection.

 

[Anonymous]

figured you might have a system like that

i can only dream

in that case go for something like the dacmagic, beresford or vdac you should notice an improvement over the ps3 with any of those

id still be tempted by the benchmark though as its better suited if ever you go down the lossless streaming road

 

[Anonymous]

Thanks guys, much appreciated

 

[Anonymous]

Craig M.:if the vdac behaves with usb the same way my dacmagic does, i would expect the optical to be a slight improvement. this is without hum from either. i would not expect the hum you get with usb to be present with optical.

A valid point but I can tell you from experience that the usb connection in the vdac is much better than the dacmagic usb. I have both and while I prefer the coax/ toslink connections on the dacmagic the usb is definately better on the vdac.

 

[Anonymous]

Fahnsen:

USB is a bad way to connect a computer to a hi-fi system.

Use an optical cable (which will also give you 24bit/96kHz abilities), or wireless.

A bit too generalised a statement I think. Have a look at Wavelength and Ayre dacs, both of which use asynchronous usb.

However....it all depends on how much you want to pay.

Clicky

Clicky

 

[matthewpiano]

I too get horrendous noise when using my HP laptop through USB into the V-DAC, but only when I am running the laptop off mains power. Using battery power on the laptop I get no such problem and it sounds excellent. Its annoying and I'm struggling to work out whether the issue is poor design in the laptop (which would surprise me as I like HP products) or some other source of mains interference or such like.

 

[Dave_]

matthewpiano:I too get horrendous noise when using my HP laptop through USB into the V-DAC, but only when I am running the laptop off mains power. Using battery power on the laptop I get no such problem and it sounds excellent. Its annoying and I'm struggling to work out whether the issue is poor design in the laptop (which would surprise me as I like HP products) or some other source of mains interference or such like.To me, the fact the noise isn't present when on battery power would suggest it's actually the laptops psu is at fault.

 

[Anonymous]

Update:

I found the noise to be an earth loop through the USB lead. Even with the IMAC off at the wall but plugged in i get a mains hum. I have not tried a filter on the Imac as I do not have a spare. I am now using the airport express to the VDAC opto and get no hum as expected. The only silight problem is you have to use Itunes with the AE , which does not support FLAC.

 

[Anonymous]

Buy Airfoil, a piece of software will allow you to stream any audio from your mac or pc to AE (including FLAC). Only £20.