Thoughts on scoping planar magnetic headphones and amplifiers.

[antbelcastro]

I would really be interesting to hearing from people that know a bit more about this than myself.
Specifically around the science and how to pick the right amplifiers for planars.

It's my understanding that they are thirsty for current, I know for example when I'm listening to my Ether flows on a Topping Dx3 Pro vs the headphone out of my stereo amplifier headphone (Cambridge Audio CX80) out a similar sound level there is a "fuller" sound heard.

Which leads me to contemplate the upgrade from the dx3 pro to potentially something like a a dx7 pro to use as a desktop friendly daily driver. Problem is I'm finding spec sheets amongst vendors are really not consistent. I'm trying to scope down a few devices to have a listen to before making a purchase.

Amir arms (thank you btw if you read this!) us with a lot of information. Currently I'm focusing on the the values of 2v4 Vrms devices / power vs distortion using a similar resistance to the headphones. Are there other factors I need to be focusing on here?

Is anyone able to share experiences about what they look for around this?

 

[Dopaminer]

+1
I am trying to figure out the exact same thing, for my newly purchased Hifiman Arya (35ohm / 90db)

 

[solderdude]

Planars, in general, are less power efficient than dynamic headphones.
The real issue is how voltage efficient headphones are.

One can have 2 headphones which are equally power efficient but have a very different voltage efficiency.
It is essential to understand that the voltage efficiency is the most important ones as audio devices provide an output voltage.

This difference is caused by a different impedance.
For the same voltage efficiency (headphones will play equally loud at the same volume setting when they have the same voltage efficiency expressed in dB/V) but having a different impedance the lower impedance headphones will draw more current and thus more power.

The problem is a specification like 35ohm / 90db says literally nothing as the dB value must be specified in dB/mW or dB/V in order to mean something. I made a very handy list that will tell you the dB/V for most well known on and over-ear headphones.
That list will also tell you how much voltage/current/power is needed to reach certain listening levels.

With those numbers you have a guide that will tell you how much power/voltage you need for your headphone(s).

This, again, is not all the info you need as amp manufacturers often only specifiy output power in only 1 or 2 impedances which isn't as simple to interpret as they might seem.

Long story short:
MOST planars are low in impedance so you need to look for an amplifier that can provide the needed power (my list) and specify that power in 16 or 32 ohm. Then you are 'safe'.
Some planars (like the Ananda) don't need much power. Headphones like the HE6SE needs much more power to go equally loud.
Both are planars and both are rather low impedance.

voltage efficiency of the headphone is important as well as output power of a headphone amp in low impedances (consider everything between 8 and 40 ohm low impedance)

 

[Ezees]

I would really be interesting to hearing from people that know a bit more about this than myself.
Specifically around the science and how to pick the right amplifiers for planars.

It's my understanding that they are thirsty for current, I know for example when I'm listening to my Ether flows on a Topping Dx3 Pro vs the headphone out of my stereo amplifier headphone (Cambridge Audio CX80) out a similar sound level there is a "fuller" sound heard.

Which leads me to contemplate the upgrade from the dx3 pro to potentially something like a a dx7 pro to use as a desktop friendly daily driver. Problem is I'm finding spec sheets amongst vendors are really not consistent. I'm trying to scope down a few devices to have a listen to before making a purchase.

Amir arms (thank you btw if you read this!) us with a lot of information. Currently I'm focusing on the the values of 2v4 Vrms devices / power vs distortion using a similar resistance to the headphones. Are there other factors I need to be focusing on here?

Is anyone able to share experiences about what they look for around this?

Generally speaking... planars require good current from an amp to get going whereas regular dynamic cans require mostly voltage. I own Aryas and I've used several different amps to find a sound that I like. The chip amps I tried (thx '887, a90, Magnius to a degree) have had a more flat-ish 2d sound - I sold them. The discrete, class A, and class AB amps I've tried (Magni 3+, Emotiva a100, Gustard h20) have that extra bit of well rounded, natural, 3d presentation that the Arya brings out - I kept those. Very subtle but detectable with the Arya. That was my journey. YMMV.

 

[abdo123]

Planars, in general, are less power efficient than dynamic headphones.
The real issue is how voltage efficient headphones are.

One can have 2 headphones which are equally power efficient but have a very different voltage efficiency.
It is essential to understand that the voltage efficiency is the most important ones as audio devices provide an output voltage.

This difference is caused by a different impedance.
For the same voltage efficiency (headphones will play equally loud at the same volume setting when they have the same voltage efficiency expressed in dB/V) but having a different impedance the lower impedance headphones will draw more current and thus more power.

The problem is a specification like 35ohm / 90db says literally nothing as the dB value must be specified in dB/mW or dB/V in order to mean something. I made a very handy list that will tell you the dB/V for most well known on and over-ear headphones.
That list will also tell you how much voltage/current/power is needed to reach certain listening levels.

With those numbers you have a guide that will tell you how much power/voltage you need for your headphone(s).

This, again, is not all the info you need as amp manufacturers often only specifiy output power in only 1 or 2 impedances which isn't as simple to interpret as they might seem.

Long story short:
MOST planars are low in impedance so you need to look for an amplifier that can provide the needed power (my list) and specify that power in 16 or 32 ohm. Then you are 'safe'.
Some planars (like the Ananda) don't need much power. Headphones like the HE6SE needs much more power to go equally loud.
Both are planars and both are rather low impedance.

voltage efficiency of the headphone is important as well as output power of a headphone amp in low impedances (consider everything between 8 and 40 ohm low impedance)

most headphone amplifiers only share their maximum voltage supply, and not their maximum current supply.

Do you happen to have another hidden list for that purpose somewhere?

 

[faheem]

Planars, in general, are less power efficient than dynamic headphones.
The real issue is how voltage efficient headphones are.

One can have 2 headphones which are equally power efficient but have a very different voltage efficiency.
It is essential to understand that the voltage efficiency is the most important ones as audio devices provide an output voltage.

This difference is caused by a different impedance.
For the same voltage efficiency (headphones will play equally loud at the same volume setting when they have the same voltage efficiency expressed in dB/V) but having a different impedance the lower impedance headphones will draw more current and thus more power.

The problem is a specification like 35ohm / 90db says literally nothing as the dB value must be specified in dB/mW or dB/V in order to mean something. I made a very handy list that will tell you the dB/V for most well known on and over-ear headphones.
That list will also tell you how much voltage/current/power is needed to reach certain listening levels.

With those numbers you have a guide that will tell you how much power/voltage you need for your headphone(s).

This, again, is not all the info you need as amp manufacturers often only specifiy output power in only 1 or 2 impedances which isn't as simple to interpret as they might seem.

Long story short:
MOST planars are low in impedance so you need to look for an amplifier that can provide the needed power (my list) and specify that power in 16 or 32 ohm. Then you are 'safe'.
Some planars (like the Ananda) don't need much power. Headphones like the HE6SE needs much more power to go equally loud.
Both are planars and both are rather low impedance.

voltage efficiency of the headphone is important as well as output power of a headphone amp in low impedances (consider everything between 8 and 40 ohm low impedance)

Many thanks for the list. That's a Huge amount of effort on your part. Thank you

 

[SlowCar]

Great list. But I am not sure if i can use it properly. As @solderdude stated

MOST planars are low in impedance so you need to look for an amplifier that can provide the needed power (my list) and specify that power in 16 or 32 ohm. Then you are 'safe'.

So i should look for 32 ohm specification. I have like OP Topping DX3Pro - as stated in review it can give 570 mW into 33 ohm. I have used https://www.rapidtables.com/ calculator to check mA value and it is 130 mA. With that value almost all headphones should work fine (aiming at 105dB) on this little Topping eg. Ether C Flow (30 mA and 20 mW) or Hifiman He 6SE (56 mA and 160 mW, but 50 ohm so can be tricky). Is that true or i have donce calculations wrong?

 

[solderdude]

105dB peak is moderately loud. When you plan to boost bass (often needed for planars) you should aim for 110 to 115dB SPL.

Ether C flow thus needs an amp that can provide 1.5V = 100mW

 

[SlowCar]

Ok, so it's better to have more than 105dB SPL. But are my calculations alright?

 

[solderdude]

The HE6SE requires 1V for 92dB so 4.5V for 105dB = 0.4W (90mA)
For 110dB you already need 1.25W in 50ohm.

 

[SlowCar]

The HE6SE requires 1V for 92dB so 4.5V for 105dB = 0.4W (90mA)
For 110dB you already need 1.25W in 50ohm.

How is this calculation done? According to table provided by You HE-6SE requires 158,38 mW, 2,8V and 56 mA for 105dB

 

[solderdude]

This is based on Amirs measurements.
I had to go off factory specs which seem to be a bit too optimistic.