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post #916 of 1684
Quote:
Originally Posted by miceblue View Post

This might be a stupid question to ask, but is there a relatively easy way to do A/B comparisons between DACs?
 

 

If you have a decent A/D converter available you could record the output of your DACs with it. Then you can easily ABX in Foobar, ideally throwing the original in as well.

This method has its problems too - it introduces the A/D converter and a second pass through the DAC when listening, but spotting the differences becomes much easier this way.

post #917 of 1684

this is from an old post of mine. warning: it in fact does not come with a regulated power supply. you will need to get one from radioshack or an electronics supply. it is very important that you have the regulated supply. it is okay to use anything from 4.5 to 5v. absolutely no more or you will fry things like your dac! 4.5v supply's actually put out about 4.7-4.8v at no load which meets usb spec. you can actually use any good hub. you will need to get the correct adapter for the psu to hub and get the polarity right or you will kill something.  do not plug anything else into the hub besides your dac! for one thing the psu you are going to get does not have enough amperage.

 

~~position the supplied cable(the side that goes into the computer) facing up towards you so you see the pins. put a little piece of scotch tape on the pin all the way to the right. make sure the pin is completely covered with tape. now plug everything in as normal and use the usb cable of your choice. I recommend Belkin gold with this. you now have clean linear isolated +5v power that is not coming from the computer. even if your dac has self power it most likely still needs +5v from the cable to sync. do not tape the ground on the left. you can also use this trick to make a data only cable if you wish. they rarely work though. now for 20 bucks you have a comparable device others sell for $200+.. good deal. there is one caveat, with jriver at least sometimes I get an error once on start and it works the second time. do not plug anything else into the hub for best sound. it sounds real good. ......this has been edited from my original post because I had misinformation at the time. others doubted it but I can measure it as good or better than any other option. of course then there are usb filters which will further increase performance which this do not have. good clean power is a good step in the right direction. a desktop or laptop computer supplies nothing but noise on usb!

 

if you have any doubts about your ability do do this don't! I thought that warning was in order even though this is very simple. I am in no way liable for what anyone does. I am simply providing instructions.

 

you can also splice the ground on the cable and ground it to something outside the computer. any solid earth ground in a building. again, do not attempt this if you are not sure of yourself!

post #918 of 1684
Quote:
Originally Posted by music_man View Post
 

this is from an old post of mine. warning: it in fact does not come with a regulated power supply. you will need to get one from radioshack or an electronics supply. it is very important that you have the regulated supply. it is okay to use anything from 4.5 to 5v. absolutely no more or you will fry things like your dac! 4.5v supply's actually put out about 4.7-4.8v at no load which meets usb spec. you can actually use any good hub. you will need to get the correct adapter for the psu to hub and get the polarity right or you will kill something.  do not plug anything else into the hub besides your dac! for one thing the psu you are going to get does not have enough amperage.

 

~~position the supplied cable(the side that goes into the computer) facing up towards you so you see the pins. put a little piece of scotch tape on the pin all the way to the right. make sure the pin is completely covered with tape. now plug everything in as normal and use the usb cable of your choice. I recommend Belkin gold with this. you now have clean linear isolated +5v power that is not coming from the computer. even if your dac has self power it most likely still needs +5v from the cable to sync. do not tape the ground on the left. you can also use this trick to make a data only cable if you wish. they rarely work though. now for 20 bucks you have a comparable device others sell for $200+.. good deal. there is one caveat, with jriver at least sometimes I get an error once on start and it works the second time. do not plug anything else into the hub for best sound. it sounds real good. ......this has been edited from my original post because I had misinformation at the time. others doubted it but I can measure it as good or better than any other option. of course then there are usb filters which will further increase performance which this do not have. good clean power is a good step in the right direction. a desktop or laptop computer supplies nothing but noise on usb!

 

if you have any doubts about your ability do do this don't! I thought that warning was in order even though this is very simple. I am in no way liable for what anyone does. I am simply providing instructions.

 

you can also splice the ground on the cable and ground it to something outside the computer. any solid earth ground in a building. again, do not attempt this if you are not sure of yourself!

Taping the ground does work for some products like audio-gd dacs. Not sure if there was a performance increase at all though as I taped both the 5v pin and the ground at the same time months ago.

post #919 of 1684
Quote:
Originally Posted by blitzxgene View Post

Quote:
Originally Posted by music_man View Post

 
this is from an old post of mine. warning: it in fact does not come with a regulated power supply. you will need to get one from radioshack or an electronics supply. it is very important that you have the regulated supply. it is okay to use anything from 4.5 to 5v. absolutely no more or you will fry things like your dac! 4.5v supply's actually put out about 4.7-4.8v at no load which meets usb spec. you can actually use any good hub. you will need to get the correct adapter for the psu to hub and get the polarity right or you will kill something.  do not plug anything else into the hub besides your dac! for one thing the psu you are going to get does not have enough amperage.

~~position the supplied cable(the side that goes into the computer) facing up towards you so you see the pins. put a little piece of scotch tape on the pin all the way to the right. make sure the pin is completely covered with tape. now plug everything in as normal and use the usb cable of your choice. I recommend Belkin gold with this. you now have clean linear isolated +5v power that is not coming from the computer. even if your dac has self power it most likely still needs +5v from the cable to sync. do not tape the ground on the left. you can also use this trick to make a data only cable if you wish. they rarely work though. now for 20 bucks you have a comparable device others sell for $200+.. good deal. there is one caveat, with jriver at least sometimes I get an error once on start and it works the second time. do not plug anything else into the hub for best sound. it sounds real good. ......this has been edited from my original post because I had misinformation at the time. others doubted it but I can measure it as good or better than any other option. of course then there are usb filters which will further increase performance which this do not have. good clean power is a good step in the right direction. a desktop or laptop computer supplies nothing but noise on usb!

if you have any doubts about your ability do do this don't! I thought that warning was in order even though this is very simple. I am in no way liable for what anyone does. I am simply providing instructions.

you can also splice the ground on the cable and ground it to something outside the computer. any solid earth ground in a building. again, do not attempt this if you are not sure of yourself!
Taping the ground does work for some products like audio-gd dacs. Not sure if there was a performance increase at all though as I taped both the 5v pin and the ground at the same time months ago.

For Audio-GD's USB-32 interface it seems that it won't matter if you tape the 5V line or not since the DAC itself severs the 5V line and does not use it even on the USB board like many XMOS implementations (see Audio-GD's explanation below). I did try taping over the ground line on my USB cable for NFB-28 and it gave a noticeable improvement (haven't ABX'd it to be sure though).

http://audio-gd.com/Pro/dac/USB32/USB32EN.htm
Quote:
The USB-32 have not connect the +5V from computer for the less disturb , so every times power on the computer then power on the DAC if applied USB playback.

Edited by gevorg - 4/13/14 at 10:18pm
post #920 of 1684

if a dac does not use +5v or has its own than it is good and there is no reason to tape it. you can externally ground it but please be sure you know how.

post #921 of 1684
Quote:
Originally Posted by music_man View Post
 

if a dac does not use +5v or has its own than it is good and there is no reason to tape it. you can externally ground it but please be sure you know how.

 

If your DAC does show up on the computer's device list when its power is off, you can be pretty sure it uses the USB power lines. Otherwise isolating the power is worth a try.

 

I found taping the connectors unreliable and ended up doing a bit of surgery on my USB cables, i.e. cutting both power and ground lines. That works for Hilo and NFB-5. If your cable has black, red, green and white wires in it, most likely it conforms with the standard: red is +5V, black is ground. White and green are the data lines so leave them alone :)  However DO THIS AT YOUR OWN RISK.

post #922 of 1684

By chance has anyone compared the Schiit Gungnir USB2 ($850) to the Arcam irDAC ($700)?

post #923 of 1684

I will try cutting the ground. the dac should be grounded to the chassis or through the powered hub. I don't think that matters anyways. it is the +5v you want to not have coming from the computer. even a plain old hub should be a lot less noisy than a pc. I did not have the ground cut on this if I remember correctly.

post #924 of 1684
Quote:
Originally Posted by purrin View Post
 

Provided you can get clean / sufficient power to the ODAC, I prefer the ODAC to the Modi. For example, I prefer the Modi from my laptop which seems to have crappy USB power. The ODAC sounded craptastic from my laptop. However the ODAC sounds great from my PC - a little better than the Modi. My PC seems to have a "real" USB port, or at least one with either sufficient juice or power quality.

 

Thank you very much for your opinion. Just wondering if you could elaborate a little bit more on how ODAC is better than Modi?

 

You mentioned in Recommendation #19 that ODAC is not so precise as Modi. Also, Modi is able to reproduce a wider range of more continuous of volumes than the ODAC. But where does ODAC beat Modi? Thanks a lot.

post #925 of 1684
Quote:
Originally Posted by PleasantSounds View Post
 

 

If your DAC does show up on the computer's device list when its power is off, you can be pretty sure it uses the USB power lines. Otherwise isolating the power is worth a try.

 

I found taping the connectors unreliable and ended up doing a bit of surgery on my USB cables, i.e. cutting both power and ground lines. That works for Hilo and NFB-5. If your cable has black, red, green and white wires in it, most likely it conforms with the standard: red is +5V, black is ground. White and green are the data lines so leave them alone :)  However DO THIS AT YOUR OWN RISK.

 

 

I thought the teac ud-501 had it's own usb power. others refuted this. I just turned it off while I watched the device manager. it instantly disappeared from the list. does that in fact mean that it does have it's own power and I have wasted my time supplying cleaner power? "If your DAC does show up..." or did you actually mean to say does-not?

post #926 of 1684
Quote:
Originally Posted by music_man View Post
 

 

 

I thought the teac ud-501 had it's own usb power. others refuted this. I just turned it off while I watched the device manager. it instantly disappeared from the list. does that in fact mean that it does have it's own power and I have wasted my time supplying cleaner power? "If your DAC does show up..." or did you actually mean to say does-not?

 

No, that statement was correct. Think about it: when the DAC is disconnected, the system is no longer displaying it. That's because it cannot be identified. When the DAC's power is down, it's similar: it still behaves as if it wasn't there. The conclusion must be that if the system is still able to identify the DAC, it must be still powered somehow. If you switched the power off, the only remaining supply is the USB power line.

 

But that does not necessarily mean that the opposite is true. It is quite possible that the DAC's power switch breaks the USB power supply as well, so the DAC chip may shut down, even if it does require USB power to operate.

post #927 of 1684
Quote:
Originally Posted by schneller View Post

By chance has anyone compared the Schiit Gungnir USB2 ($850) to the Arcam irDAC ($700)?




Good question. I would also like to know.
post #928 of 1684

when I used a data only cable it did not work. however it may require +5v to handshake with the pc. I am pretty sure it has it's own power but others said no. it would seem any dacs power switch would break the usb power. if the dac chip is off it will not receive power thus not display in device manager I would thing. just like if you connect a camera,phone etc and turn it off. I guess I don't know if it actually is self powered. the board appears to be but I just can't be sure without a schematic. just for the sake of it I am supplying clean power. I will try cutting the ground since I assume the usb hub provides that as well.

 

is there any to actually know for sure if the dac provides it's own usb power?

post #929 of 1684
Quote:
Originally Posted by music_man View Post
 

when I used a data only cable it did not work. however it may require +5v to handshake with the pc. I am pretty sure it has it's own power but others said no. it would seem any dacs power switch would break the usb power. if the dac chip is off it will not receive power thus not display in device manager I would thing. just like if you connect a camera,phone etc and turn it off. I guess I don't know if it actually is self powered. the board appears to be but I just can't be sure without a schematic. just for the sake of it I am supplying clean power. I will try cutting the ground since I assume the usb hub provides that as well.

 

is there any to actually know for sure if the dac provides it's own usb power?

 

Not too sure if cutting the ground is a good idea, especially if one (or both) of the transmitting and receiving devices is floating (not grounded).

post #930 of 1684
Quote:
Originally Posted by music_man View Post
 

when I used a data only cable it did not work. however it may require +5v to handshake with the pc. I am pretty sure it has it's own power but others said no. it would seem any dacs power switch would break the usb power. if the dac chip is off it will not receive power thus not display in device manager I would thing. just like if you connect a camera,phone etc and turn it off. I guess I don't know if it actually is self powered. the board appears to be but I just can't be sure without a schematic. just for the sake of it I am supplying clean power. I will try cutting the ground since I assume the usb hub provides that as well.

 

is there any to actually know for sure if the dac provides it's own usb power?

 

Using PWD 2, I taped both ends of usb cable at laptop end and works just fine. SQ is bit better.

 

not all dac uses +5v for handshake.

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