Tuesday, December 13, 2011

Xonar DX output impedance

~86Ω @ ?V into 33Ω load
~108Ω @ 0.15V into 16Ω load

Update 23/03/12: I remeasured again with a 16Ω load @ -22.7dB into a 16Ω load and got 108Ω. I will try to remeasure when I get another 33Ω load working, but I'm expecting both figures to be correct. I'll post the possible explanation once I confirmed the numbers.

Well you don't have to read the rest of my blabbering, but if you want to,

Well I needed to find this, so might as well give it its own post so people can find it on Google.

So I measured this guy, -11.1 to -11.2dB with a 33ohm resistor load. Well that's the problem with my current measurement method and the use of a logarithmic scale. The output impedance is in the range of ~86Ω, and highly resistive in nature, at least that's what the FFTs say.

No load (or whatever the load of Xonar DX's input is)

33Ω resistor

Well you can see that the frequency-dependent portion starts at below 20Hz.

Hmm why 86Ω? 82Ω resistor + 4Ω from everything else? Only by looking at the card can I know for sure, and I don't feel like doing that.

But well, with such an output impedance (resistance), it isn't going to drive phones without screwing up the frequency response. (This sentence have something to do with another post coming up.)

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