DAC's XLR-outs direct to headphones?

[yates7592]

I'm planning / hoping to use my DAC's 3-pin XLR outputs to temporarily drive headphones until funds allow an appropriate amp purchase. The DAC is Denafrips Terminator with 4.6V on the XLR outs. I seem to remember reading somewhere that not all DAC's are suitable or even safe (power requirement aside) to use directly with headphones depending on the impedance match (?). My cans are various 15ohm, 110ohm and 300ohm impedance. Would this be OK for any/some?

 

[MindsMirror]

Your DAC's XLR output impedance is 1250 Ohms. You want the output impedance to be at least 8 times lower than the headphone impedance, not the other way around at 4 to almost 100 times higher in the case of the 15 Ohm ones. It will make sound that might be loud enough depending on the headphone's sensitivity, and it shouldn't damage itself, but you'd be better off listening to a smartphone or PC instead.

 

[BLacklWf]

I'm planning / hoping to use my DAC's 3-pin XLR outputs to temporarily drive headphones until funds allow an appropriate amp purchase. The DAC is Denafrips Terminator with 4.6V on the XLR outs. I seem to remember reading somewhere that not all DAC's are suitable or even safe (power requirement aside) to use directly with headphones depending on the impedance match (?). My cans are various 15ohm, 110ohm and 300ohm impedance. Would this be OK for any/some?

Your DAC's XLR output impedance is 1250 Ohms. You want the output impedance to be at least 8 times lower than the headphone impedance, not the other way around at 4 to almost 100 times higher in the case of the 15 Ohm ones. It will make sound that might be loud enough depending on the headphone's sensitivity, and it shouldn't damage itself, but you'd be better off listening to a smartphone or PC instead.

I second this opinion. First, it will more likely be way too loud. You could try a passive attenuator (volume control) but finding a passive attenuator with XLR input may be hard. Second, you may not get enough gain with hard to drive headphone although the volume is too loud. For your easy to drive headphones, it may work with a passive attenuator.

 

[ReignofError]

1250 ohm output impedance seems absurd for such a respected design. Typo?

 

[ostewart]

1250 ohm output impedance seems absurd for such a respected design. Typo?

It's a line out, not a headphone out. Which means that sounds about right.

 

[mtoc]

Your DAC's XLR output impedance is 1250 Ohms.

whose dac would have 1.25k output z??? should be 100ohm bal / 50ohm unbal, normally

to op: make sure to use high impedance cans like 600 ohms ones

 

[ostewart]

whose dac would have 1.25k output z??? should be 100ohm bal / 50ohm unbal, normally

to op: make sure to use high impedance cans like 600 ohms ones

With line level signals impedance matching is not important. From Wikipedia:

"As cables between line output and line input are generally extremely short compared to the audio signal wavelength in the cable, transmission line effects can be disregarded and impedance matching need not be used. Instead, line level circuits use the impedance bridging principle, in which a low impedance output drives a high impedance input. A typical line out connection has an output impedance from 100 to 600 Ω, with lower values being more common in newer equipment. Line inputs present a much higher impedance, typically 10 kΩ or more"

So a line output impedance of 1250 ohms is not an issues. But it is not made to be used to drive headphones directly and I wouldn't advise it.

https://en.m.wikipedia.org/wiki/Line_level