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Do planar magnetics really benefit from powerful headphone amps?

Pe8er

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#1
Hey everyone!

I'm looking for a new amp for my Audeze LCD-X. I'm currently using Woo Audio WA-7 and I'd like to move away from tubes: I just want to make sure the headphone receives the cleanest signal possible and is driven properly.

I've been interested in confirming whether or not planar magnetic headphones supposedly benefit from high powered amplifiers. I wasn't able to find any finite evidence that confirms or debunks this assertion, so I thought I'd grab a couple high quality amps and test myself.

I zeroed in on JDS Labs Atom/Element to test the "low" (or perhaps I just say "just enough") power situation. For something "overpowered" I considered THX AAA 789, but it's out of stock. Looking through Amir's reviews and the forum in general, I haven't been able to find anything that quite matches its quality and power. I've got my eye on Monoprice AAA Monolith, but I thought I should ask if I'm missing anything.

Since Audeze recommends 1-4W for this headphone, I'd love to get something 2W and upwards. I don't care whether it's balanced or SE. Budget is up to $1,000. Any ideas?

Also, how do planar magnetics behave with "overpowered" amps in your experience? Is there any science backing up this idea?

Thank you!
 

solderdude

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#2
The LCD-X is 21 Ohm.
At 1V it produces 108dB .. that's 50mW.
At 4.6V it draws 1W and can produce 121dB peak.
At 6.5V it draws 2W and can produce 124dB peak SPL.

Do you think your ears really need that ?

The Atom will be able to deliver 3.9V into the LCD-X = 0.7W so can reach 119 dB peak SPL (about 90-95dB average) and is 5dB less than the 2W amp will do.

It is not easy to 'overpower' the LCD-X. It can handle 15W 'peaks' in music (not continuous) = 133dB peak SPL.
For this you need 18V = 80W/4Ohm amp on the speaker terminals or 40W/8Ohm amp.
You will be wondering why the world around you will have gone quiet so suddenly.
 
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Pe8er

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#3
You are correct, but I've seen arguments that there is more to it than just SPL. I don't fully understand the physics, which is why I'm looking for advice here. Apparently planars can produce more bass or more controlled bass with more power. Is that mumbo jumbo? I want to find out.
 

solderdude

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#4
Not specifically planars ... just the ones with the huge power rating and magnets on both sides like the LCD series.
The 'control' bit is nonsense.



When you want to play bass impressively loud at say 100 Phon then you need 110dB SPL of sound pressure.
100 Phon is really, really loud.
BUT on top of that bass swing there are also other 'instruments' added to that signal.
This means you need to have a voltage swing that is substantially higher than what's needed for the 100Phon bass.
You will have to have at least enough voltage to reach 120dB.
The Atom can already do that so is 'power' enough.

There really isn't anything else than just SPL.
When I play back music reaching peaks of say 0.5W (undistorted) with a 1W amp and a 100W amp then there really is no difference between them.
There is no 'magic' to the higher wattage... there is not more 'grip' nor more 'control'.
A 4V signal is a 4V signal. It isn't any different when it is coming from a 1W amp or a 1000W amp.
At 4V both amps deliver 0.19A. It really does not matter if amp 1 can deliver max 0.22A or max 200A.
In both cases the current will be 0.19A regardless how much power is available.

The rest is mumbo jumbo, hear say, assumptions and sighted listening experiences people form their opinions on.

In general most headphones benefit from a more powerful headphone amp. Some extra headroom can never hurt. That is with the exception of low power and sensitive low impedance headphones/IEM's that is. In that case accidentally blowing up drivers is a real probability.
 
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