[magiccabbage]

Basically, keeping all else equal, you can increase a driver's sensitivity by either using a stronger magnet, or by putting more turns of wire on the voice coil. It seems like Audeze has gone for the latter, with their "ultra-high-density voice coil." That would increase the sensitivity as well as the impedance of the voice coil, which appears to be the case her given their 106dB sensitivity. All in all a good thing. A planar with the sensitivity usually reserved for dynamic headphones. And that 1,200 ohm impedance would indeed be a godsend for OTL amps.

Good on Audeze.

se

What about an amp like the WA2?

 

[Steve Eddy]

http://www.innerfidelity.com/content/canjam-rmaf-2014-audeze-prototype-z-high-impedance-planar-magnetic-headphone

What about the handout that states: The Prototype-Z can be driven with any regular voltage-mode amplifier, but better results can be achieved with high quality current-mode amplifiers like the BAKOON. Current-mode amplifiers work very efficiently into this type of load and will be louder at the same volume setting than any other headphone. Voltage-mode amplifiers will require the volume knob to be higher to generate proper driving power into such high impedance modes.

Yes, I saw that. But I don't have any idea what the reasoning behind it was. I do know however that there's a lot of misunderstanding out there regarding current source amplifiers.

se

 

[Steve Eddy]

What about an amp like the WA2?

Yup. Should be a nice pairing.

se

 

[Stereolab42]

What the heck is "current-mode" vs. "voltage mode"? That makes no sense. An amp can't "choose" to push more current into a load, it can only choose to increase the voltage of the signal. It's up to the load to demand current.

 

[Steve Eddy]

What the heck is "current-mode" vs. "voltage mode"? That makes no sense. An amp can't "choose" to push more current into a load, it can only choose to increase the voltage of the signal. It's up to the load to demand current.

The load determines current when driven by a voltage source. A current source however delivers a given current and the voltage across the load is determined by the load.

Most all amps behave as voltage sources, however there are a few companies, such as BAKOON, who offer current source amplifiers.

You can approximate a current source amplifier by using a voltage source amplifier to drive the load through a high value series resistor. Of course the voltage source amp would need to have enough gain and voltage swing to overcome the voltage divider loss that the resistor brings to the table.

se

 

[Makiah S]

The load determines current when driven by a voltage source. A current source however delivers a given current and the voltage across the load is determined by the load.

Most all amps behave as voltage sources, however there are a few companies, such as BAKOON, who offer current source amplifiers.

You can approximate a current source amplifier by using a voltage source amplifier to drive the load through a high value series resistor. Of course the voltage source amp would need to have enough gain and voltage swing to overcome the voltage divider loss that the resistor brings to the table.

se

whoa... that was well a nice explination! 

 

[Rem0o]

This whole current domain thing is pure sorcery to me compared to the voltage domain, just like the frequency domain is to the time domain. I can do the math, and I have to in college right now, but it makes no sense to me.

 

[Shazb0t]

Basically, keeping all else equal, you can increase a driver's sensitivity by either using a stronger magnet, or by putting more turns of wire on the voice coil. It seems like Audeze has gone for the latter, with their "ultra-high-density voice coil." That would increase the sensitivity as well as the impedance of the voice coil, which appears to be the case her given their 106dB sensitivity. All in all a good thing. A planar with the sensitivity usually reserved for dynamic headphones. And that 1,200 ohm impedance would indeed be a godsend for OTL amps.

Good on Audeze.

se

 
I'm Confused.  These are planar magnetic, where is the voice coil?  Do people call the diaphragm tracings voice coils?  I'm not an expert so asking seriously. 

 

[bonesnv]

I was more interested in the part that stated Audeze was working on an OTL amp for them as well.
 
Curious what that's going to be like.

 

[Steve Eddy]

I'm Confused.  Wouldn't stronger magnets require more power to move the diaphragm = less sensitive?  Also, these are planar magnetic, voice coil?  Do people call the tracings voice coils?  I'm not an expert so asking seriously. 

Both planars and dynamic drivers work by way of sending current through wires that are immersed in a fixed magneti field, that's provided by the permanent magnets that are common to the design of both types of speakers. When current flows through the wire, it creates a magnetic field. That magnetic field, and whatever is producing it is either repelled or attracted by the magnetic field produced by the fixed magnets. So for a given amount of current producing a given magnetic field, it will be more strongly repelled or attracted if the strength of the fixed magnetic field is greater. In other words, for the same current, the diaphragm will move further, and have greater amplitude, producing a louder sound.

And yes, in planars, the tracings on the diaphragm are also called voice coils. While they're not literally coiled around a former the way they are in dynamic drivers, they serve the same function so the same term was used to describe them.

se

 

[eric65]

  I was more interested in the part that stated Audeze was working on an OTL amp for them as well.
 
Curious what that's going to be like.

 
Hum .., I know a good German brand that manufactures an OTL headphone amplifier that works very well with high-impedance headphones : like Sennheiser HD 600-650-800 or difficult to feed (AKG K1000) : 3 Watt sinus at 200 Ohm and 80 Volt RMS output at 2000 Ohm. Moreover, it works also very well with a very high impedance headphone (Stax ...)

 

[Stereolab42]

The load determines current when driven by a voltage source. A current source however delivers a given current and the voltage across the load is determined by the load.

Most all amps behave as voltage sources, however there are a few companies, such as BAKOON, who offer current source amplifiers.

You can approximate a current source amplifier by using a voltage source amplifier to drive the load through a high value series resistor. Of course the voltage source amp would need to have enough gain and voltage swing to overcome the voltage divider loss that the resistor brings to the table.

se

 
I found this also:
 
http://www.customanalogue.com/various/Current-Amplification.pdf
 
I realize now that Ohm's law insists that if the amp keeps current constant, then yes, the fixed resistance/impedance of the load will determine what voltage it receives. But it's certainly more difficult to wrap your head around. I wonder what would happen if you hooked a multimeter to the speaker output of a current-mode amp and jacked the volume... fireworks?

 

[preproman]

Subbed.
 

 

[SilverEars]

I've read the OTL cap coupled output.  The high-Z will prevent bass roll-off from the caps.  

 

[groovyd]

I have already bought a pair of LCD-Z and LCD-ZC in my head... just wake me when it is time to put my finger on the touchId