[milkweg]

I have a LunchboxPro but no spec sheet came with it and the EC site doesn't list the output impedance. I have DT990pro headphones and I have read that these headphones are best with 120ohm output impedance so am trying to determine if I need to buy 120ohm adapter or not.

 

[olblueyez]

It is 123.7 Ohms and taking this into account I would rush out and get an adapter ASAP.

 

[Donald North]

Quote:

Originally Posted by milkweg /img/forum/go_quote.gif I have a LunchboxPro but no spec sheet came with it and the EC site doesn't list the output impedance. I have DT990pro headphones and I have read that these headphones are best with 120ohm output impedance so am trying to determine if I need to buy 120ohm adapter or not.

I suggest e-mailing Eddie Current and ask them. They should know or be able to quickly measure.

 

[cristox]

How can i measure the output impedance of my DAC and my Headphone amp?
I do have a multimeter.

 

[olblueyez]

Every person I have talked with says that adding an adapter will degrade the sound quality. If you have enough volume travel I would leave it alone.

 

[Donald North]

Quote:

Originally Posted by cristox /img/forum/go_quote.gif How can i measure the output impedance of my DAC and my Headphone amp? I do have a multimeter.

To measure the output impedance of a DAC or headphone amp, you need to perform two measurements using 2 precisely known different resistors, keeping the input signal level the same. With the value of each resistor and voltage measured across it, you can then calculate what the amp's internal output impedance is using Ohm's law.