[wutsound]

I have:
 
Creative Sound Blaster ZxR
Sennheiser hd600
 
In the driver, it allows me to choose Normal Gain (32/300 ohm headphones) and High Gain (600 ohm headphones). 
 
Which should I choose? (it says "Setting to high gain may damage your headphones if their impedance does not match the specified level of 600 ohms.)

 

[MrViolin]

Quote:

I have:
 
Creative Sound Blaster ZxR
Sennheiser hd600
 
In the driver, it allows me to choose Normal Gain (32/300 ohm headphones) and High Gain (600 ohm headphones). 
 
Which should I choose? (it says "Setting to high gain may damage your headphones if their impedance does not match the specified level of 600 ohms.)

Then I guess it'd be better to stick w/ the lower ohms. More ohms= more voltage, so you might end up frying your drivers. But it really depends on how much voltage your phones can handle and how much power the card is putting into your phone. Since it's a card, I doubt it'd be able to fry the hd600. But I'd stay away from it personally. 

 

[Heli0s]

Well, let's take a look at the HD600 product data to first find the impedance.
http://en-us.sennheiser.com/downloads/92eb813de08987eaedf66b9777bd6bdc.pdf
 
 
Technical Data

Frequency response	12 – 39,000 Hz (–10 dB/1 kHz)
Transducer principle	dynamic, open
Frequency characteristic	diffuse field equalised
Nominal impedance	300 Ω
Characteristic SPL	112 dB (at 1 kHz, 1 Vrms)
Load rating	0.2 W
THD	≤ 0.1 %
Ear coupling	circumaural
Contact pressure	approx. 2.5 N
Weight (without cable)	260 g
Connector	3.5 mm Ø stereo mini jack plug
Connection cable	3 m, detachable dual-sided, OFC copper cable

We see that the impedance is 300Ω, so I would suggest the Normal Gain setting.

 

[Heli0s]

Quote:

More ohms= more voltage

 
I think what you may have meant was...an amp gain setting meant for higher impedance headphones = higher power output.
For example, as you increase the value of a resistor (in ohms) in a circuit, the current (amps) and power (watts) will decrease. 
 
We're not concerned with voltage as much as power dissipation in watts.
As we increase the impedance (measured in ohms) of a headphone connected to an amp, the headphone's voicecoil will dissipate fewer watts (voltage x current).
 
For instance, I have an 8 ohm loudspeaker that is dissipating 100 watts from an amp. If I connect a 16 ohm loudspeaker, this new speaker will dissipate 50 watts. If I connect a 4 ohm speaker, it will dissipate 200 watts. Of course this is all assuming the amplifier is stable with such a low load impedance and such high wattage.
 
Power = Voltage * Voltage / Impedance
 
If you take a look at the ZxR specs, You'll see that the headphone's amp power output with a 600 ohm load is 80mW. This must be the High Gain setting. My guess is that when you switch between these gain levels, a relay switches between feedback resistors to alter the headphone amp gain per the TI TPA6120 datasheet...or it could be a digital resistor, but now we're just splitting hairs. Disconnect your headphones, and switch this setting back and forth; do you hear a click from the soundcard? Just curious.
 
ANYWAY
So what happens if we use 300 ohm headphones in the High Gain 80mW mode? The headphones now have to dissipate 160mW of power or 0.16W.
 
Now look back at the "Load Rating" of the HD600 = 0.2W. You might be able to safely use High Gain mode, but you'd be cutting it a little too close to your headphone's power handling limits for my tastes (assuming that "Load Rating" is Sennheiser's way of saying "Power Handling").
 
So, best to stick with Normal Gain.

 

[Tsujigiri]

Does it play loud enough for you on normal gain?

 

[wutsound]

Thanks for the info everyone.
 
I do hear a switch/click when I change from normal gain to high gain.

 

[chrislangley4253]

Yeah, play them on normal.. if it gets loud enough, leave it.. if not, try high. It shouldn't damage anything.