[fewtch]

Quote:

Originally Posted by headphone-n00b Now my head hurts... I thought that a "higher" impedence (300 ohm is higher than 50 ohm, right?) meant "more" resistance.

Correct.
Quote:

Wouldn't this imply that you'd need more power to drive the HD-650's?

More voltage, less current.

 

[sgrossklass]

Quote:

Originally Posted by headphone-n00b Now you're telling me that a LOWER powered output will drive HIGHER impedence cans better than lower impedence cans. I'm confused.

The reason is very simple: The voltage swing an opamp can deliver is mainly determined by the supply voltages it's run off and usually plenty (supply usually is off +/- 5V or +/- 12 V). However, opamps are not really built for high output currents, and the old TL072 is a good example - it has a fairly high slew rate, but the output current is limited to 5 mA. This kind of opamp does not like low-impedance loads and will distort pretty badly - accordingly the output could drive 2kOhm HD424s rather well (if only to modest volume), while with 120 ohm HD590s the sound was pretty harsh. Now the opamps typically used on sound cards aren't as limited in current as the old TL072 - a 4580 manages up to 100 mA, a 4556 a bit more still, but I'd still have my doubts about very low-impedance stuff (24 or 16 ohm) when the output impedance is low.

Now on portable devices the situation is quite different - low supply voltages of typically 3 V max dictate the use of little power amp chips to get some output power even with little voltage swing, and accordingly low-impedance cans are required. Output current is less of a problem.

 

[headphone-n00b]

Ok, so this means that since I've settled on the HD-595's (and it looks like I'll be getting the 50 ohm version), I need to find a PC sound card that will play nice with them? Or do I just get whatever sound card I want and throw an amp in line?

Hmm... I can actually get the 120ohm version new from an authorized dealer for $175... anyone have any opinions?

 

[DarkScorpion]

Still going with the "budget" idea, I'd say get a PA2V2 and an AV-710. At least with the PA2V2, you can use it with mobile devices, but that's just me.

 

[headphone-n00b]

I've heard the AV-710 has piss-poor game performance... and I do play a lot of games, so I've ruled it out at this point. On another note, the 120 ohm version is now back in the running, see the 120 vs. 50 thread in "headphones".

 

[CingKrab]

If you've got an Audigy, you can just keep that for games and add a music only card. I have an Audigy and an 0404 and it works pretty well. I use to have an AV-710 and that worked well too.