How much power is optimal for Hifiman HE-400i?

[shaney777]

How much power is optimal for Hifiman HE-400i? I keep hearing that 2W per channel is needed, but Amir brags on HE-400i bass in his review of the JDS Labs Atom amp, which has 1W per channel. I am wondering if the Schiit Heresy might sound better with HE400i because of the 2.4W of power per channel. If 2W is not needed, where did this idea come from and why is it so popular?

Also, is it recommended to use high gain with planars? I keep hearing not to use high gain unless you absolutely have to due to increased noise/distortion, but is low gain actually taking full advantage of the 1W of power???

 

[kneepel]

The HE-400i has a sensitivity of 93.82 dB/mW SPL, so to get to 115 db SPL (very loud!) you would need an amplifier that could provide 131 mW at 35 ohms.

2w would probably destroy the drivers, or at the very least your ears as 120 db SPL would only require ~430 mW and that is definitely too loud.

Just use the lowest gain you can that still allows you to listen at an enjoyable volume, higher gain = more noise so best to only use if you need more power.

(I use an xduoo xd-05 for reference, and 2:00 at low gain is usually all it takes for me to enjoy the volume).

 

[shaney777]

The HE-400i has a sensitivity of 93.82 dB/mW SPL, so to get to 115 db SPL (very loud!) you would need an amplifier that could provide 131 mW at 35 ohms.

2w would probably destroy the drivers, or at the very least your ears as 120 db SPL would only require ~430 mW and that is definitely too loud.

Just use the lowest gain you can that still allows you to listen at an enjoyable volume, higher gain = more noise so best to only use if you need more power.

(I use an xduoo xd-05 for reference, and 2:00 at low gain is usually all it takes for me to enjoy the volume).

131 mW sounds very low to me. Isn't a normal headphone jack capable of this? A normal headphone jack can get it to very loud levels, but there is significantly less bass/impact/body than when used with an amp.

 

[kneepel]

131 mW sounds very low to me. Isn't a normal headphone jack capable of this?

I mean, a fair number of devices can definitely push 131mW at 35 ohms as that's ~2.2v with that load(not to say there aren't a lot of devices with very anemic outputs!). Despite what many reviewers say, HE-400i's are not hugely difficult to power and I've definitely enjoyed them on my old LG v30 at reasonable levels.

A normal headphone jack can get it to very loud levels, but there is significantly less bass/impact/body than when used with an amp.

And that's to be totally expected, a dedicated amp will usually have much more headroom and generally the qualities you mentioned will get better the louder you're driving your headphones, although you really shouldn't need more power than stated above to get too loud to comfortably enjoy for an extended period of time.

 

[shaney777]

I mean, a fair number of devices can definitely push 131mW at 35 ohms as that's ~2.2v with that load(not to say there aren't a lot of devices with very anemic outputs!). Despite what many reviewers say, HE-400i's are not hugely difficult to power and I've definitely enjoyed them on my old LG v30 at reasonable levels.



And that's to be totally expected, a dedicated amp will usually have much more headroom and generally the qualities you mentioned will get better the louder you're driving your headphones, although you really shouldn't need more power than stated above to get too loud to comfortably enjoy for an extended period of time.

Thank you for the information. I agree that they definitely sound decent unamped, just not exactly as fun or memorable?
I know someone in a different forum said that 2.4W was so much that they could barely move the volume pot without it being too loud. I need to go see if they were actually referring to use with planars.