How efficient are the Proline 750's ?

[Spiug31]

Hi all,
I'd like to know how efficient the Proline 750's are when compared to any of these three:

HD650
Sony MDR-V6
Sony MDR-7506

There doesn't seem to be much information around about this so I'd appreciate some help.
I'm trying to work out if these are than the HD650's at the same voltage.

Thanks

 

[Spiug31]

All I need to know is if the Proline 750's are louder than the HD-650
so that I can be sure that my 750's will work on an amp that strugles to fully power the HD650's.

 

[scratchyvinyl]

The Proline 750s have an impedance of 40 Ohms. Since I don't have an HD650 (I have an HD580, which is rated at 300 Ohms) and my Proline 750 is currently in storage, I can't readily compare the two. But from what I recall of the Proline 750s, they are louder than the HD580s running from an iPod, a Powerbook headphone out and a Panasonic PCDP (all unamped). Hope this helps.

 

[Spiug31]

That points me in the right direction, thanks scratchyvinyl.

If anyone can do an A/B comparison and report their findings here, that would likely settle it for me.

 

[Spiug31]

I've just heard back from Ultrasone and the Proline 750's efficiency is 100dB/mw
Checking the table toward the bottom of http://www.siteswithstyle.com/VoltSe...eadphones.html it seems the Proline 750 is efficient enough for the amp I was looking at.

My thanks to pburke for helping me with this.