[emericanchaos]

http://www.guygraphics.com/GGPROD-647.html

M-Audio Audiophile USB

i'm going to be powering 250ohm beyer's.

 

[emericanchaos]

maybe i need to clarify my intent a bit.

from what i understand external DAC's are mucho better when running CAS. add to that, source is null when running external DAC.

could i not plug in the audiophile to the AC run coax out from the card i have into it and simply use it as a DAC with headphone out?

i guess it kinda become null cause i could use the whole unit to the same avail so maybe the question is:

can i power 250ohm beyer's with this thing?

 

[joe_cool]

Yes, the headphone output impedance is probably 25-50 ohms so a 250 ohm load is no problem. However, you may not get enough volume, depending on the efficiency of your headphones.

 

[emericanchaos]

Quote:

Originally Posted by joe_cool /img/forum/go_quote.gif Yes, the headphone output impedance is probably 25-50 ohms so a 250 ohm load is no problem. However, you may not get enough volume, depending on the efficiency of your headphones.

what's "efficiency" exactly? db/mW?

 

[joe_cool]

Yes, but not exactly easy to compare.

Db/mw is power efficiency but is related to impedance. Higher ohms requires higher voltage but less current. Lower ohms requires less voltage but more current.

So not exactly some people say a high impedance (250 or 300 ohms) phone is "harder" to drive because it requires more voltage (but less current), and say a low impedance phone is "easier" to drive because it requires less voltage (but more current).

So some manufacturers rate their products as db/volt which is relative loudness per voltage level. This is less exact in terms of power but gives a better representation of how loud a phone will sound when connected to a specific device (regardless of impedance or current).

Check here for another option.

 

[emericanchaos]

Quote:

Originally Posted by joe_cool /img/forum/go_quote.gif Yes, but not exactly easy to compare. Db/mw is power efficiency but is related to impedance. Higher ohms requires higher voltage but less current. Lower ohms requires less voltage but more current. So not exactly some people say a high impedance (250 or 300 ohms) phone is "harder" to drive because it requires more voltage (but less current), and say a low impedance phone is "easier" to drive because it requires less voltage (but more current). So some manufacturers rate their products as db/volt which is relative loudness per voltage level. This is less exact in terms of power but gives a better representation of how loud a phone will sound when connected to a specific device (regardless of impedance or current). Check here for another option.

excellent post, thank you.

why would the firewire version be better? i didn't know if this mobo had firewire so i was shopping strictly USB. i googled and realized that i do so: advantages?

 

[illy2k]

firewire is faster than USB2.0 so theoretically it would have better throughput using firewire. Also the specs of the Firewire Audiophile are slightly different from the USB Audiophile. The firewire audiophile has higher frequency range, and has a few more advanced features than the USB counterpart. If you can get the firewire version I would recommend that. Happy listening