[ericwzy]

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[ProtegeManiac]

Quote:

Originally Posted by ericwzy /img/forum/go_quote.gif

 

How does the output impedance of a DAC affect sound? I've heard about the 1/8th rule, but have yet to find a definitive answer online. I was thinking that it shouldn't be very relevant if you are passing it through an amp, but is this the case? And if the 1/8th rule does apply even after going through an amp, what should I do about high sensitivity+low impedance headphones like the AKG K550? (I don't think it really need an amp)

 

I would still like to plug it into my DAC for sound quality, but if the 1/8th rule is a thing, then 75 ohms output impedance on the DAC vs 32 ohms impedance on the headphones is far off from the 1/8 ratio. 

 

I hope you guys can explain how output impedance really works for a DAC and clear up any myths that may be circulating. I'm just wondering how I should use a Schiit Bifrost + Amp for a pair of AKG K550s. I want to use the DAC on both the HD650 (which is fine) and K550.

 

It doesn't matter. Technically it would matter for the input impedance of the amplifier that comes after the DAC, but amplifier input impedance is always very high. This isn't like headphones where there would be some kind of trade off (hence, there would be some benefit) if they went with low impedance. I don't recall any amplifier having an input impedance lower than 500ohms. Even if the amp had an output impedance of 75ohms and the headphone had 600ohms, at that high load nominal impedance the 8:1 "rule" doesn't matter as much unless the headphone's impedance swings downward on some frequencies.

 

[MindsMirror]

The DAC's output impedance has no interaction with the headphone when you are using an amp in between. The amp acts like a buffer. The DAC only sees the amp's input, and the headphone only sees the amp's output.

 

[PurpleAngel]

  I am looking for a DAC and amp since I will probably be getting a HD650 soon, unless something else nice shows up on Massdrop. The Schiit Bifrost (75 Ohms output impedance) looks like a good option since it is modular and hence upgradable. For the amp I am looking at a Vali or Asgard (which one would you guys recommend?). The setup above is fine for HD650s, but I want to know how well it would work for low impedance headphones.
How does the output impedance of a DAC affect sound? I've heard about the 1/8th rule, but have yet to find a definitive answer online. I was thinking that it shouldn't be very relevant if you are passing it through an amp, but is this the case? And if the 1/8th rule does apply even after going through an amp, what should I do about high sensitivity+low impedance headphones like the AKG K550? (I don't think it really need an amp)
I would still like to plug it into my DAC for sound quality, but if the 1/8th rule is a thing, then 75 ohms output impedance on the DAC vs 32 ohms impedance on the headphones is far off from the 1/8 ratio. 
I hope you guys can explain how output impedance really works for a DAC and clear up any myths that may be circulating. I'm just wondering how I should use a Schiit Bifrost + Amp for a pair of AKG K550s. I want to use the DAC on both the HD650 (which is fine) and K550.

 
The line-output from a DAC (Schiit Bifrost) is not intended for driving headphones.
So even a $60 headphone amplifier, like the FiiO A3, is better at driving headphones, then the line-output from a DAC.
 
The impedance of the connection, between the DAC and headphone amplifier, does not effect (impedance wise) the headphone jack of the amplifier (the amplifier that is connected to a DAC).

 

[ericwzy]

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