[billcoke]

Recently I bought a Senn PXC 450 Noise Canceling for my Iphone. I intend to hook up the PXC 450 to my Iphone via the Fiio E1 amp. According to PXC 450 spec, it has an impedance of 750 ohm (active) and 150 ohm (passive)? What exactly is active and passive? Can't find the definition in Google.

Secondly, the Fiio E1 amp supports up to 300 ohm, so is the E1 sufficient to support the PXC 450?

I'm searching for a portable amp, would Fiio Line Out cable pair up with Ibasso D2+ Dao or Ibasso P3+ be good enough?

 

[Gbjerke]

Quote:

Originally Posted by billcoke /img/forum/go_quote.gif Recently I bought a Senn PXC 450 Noise Canceling for my Iphone. I intend to hook up the PXC 450 to my Iphone via the Fiio E1 amp. According to PXC 450 spec, it has an impedance of 750 ohm (active) and 150 ohm (passive)? What exactly is active and passive? Can't find the definition in Google. Secondly, the Fiio E1 amp supports up to 300 ohm, so is the E1 sufficient to support the PXC 450? I'm searching for a portable amp, would Fiio Line Out cable pair up with Ibasso D2+ Dao or Ibasso P3+ be good enough?

Bummer

Anyways the PXC 450 has a built in amp. A new portable amp hardly makes a difference. The P3+ maid it even less bassy, and added some transparancy but it wasn't worth200 bucks. I don't think the fiio will make any difference at all but distortion. If i was you, I'd sell the pxc 450 right away and get the hd 25 II. A lot more practical, and almost as noise isolating. The PXC is a job to cary with you and the soundquality you get with the noise cancelling on is really not good.

 

[ear8dmg]

All active noise cancelling headphones have a built in amp don't they ? - otherwise they wouldn't work. It's required for playing noise out of phase with ambient.

My Goldring NS1000s are about 100 ohm passive and 300 ohm active. Thanks to the built in amp they are very easy to drive in active mode.

Passive mode is a different story. I'm not sure what the mW rating is but I think they need quite a bit of current. From a good number of soundcards and pmps I've tried passive mode is awfully muddy with overly boomy bass. Add an adequate amp (even my FiiO e5 or cheap CMOY helps) and the bass is tamed and the treble and mids tidy up a lot.

From most sources - active mode actually sounds better thanks to the onboard amp. It takes an amp capable of putting out quite a bit of current at 100 ohms to get passive mode sound quality to match active mode.

Edit: To answer the question - 'Active' is noise cancelling and built-in amp turned on. 'Passive' has them turned off.

 

[billcoke]

Quote:

Originally Posted by ear8dmg /img/forum/go_quote.gif All active noise cancelling headphones have a built in amp don't they ? - otherwise they wouldn't work. It's required for playing noise out of phase with ambient. Edit: To answer the question - 'Active' is noise cancelling and built-in amp turned on. 'Passive' has them turned off.

Now I get it. Even impedance is high in "Active" mode, the built-in amps inside the headphone helps to drive the cans.

I tested the Senn PXC 450 with the Fiio E3 amps, can hear that the soundstage is better and wider. Am looking for to test the Fiio E1 amps, only concern is the battery, was informed that it drains ~10% of the battery.

 

[dsawatzky]

...
Edit: To answer the question - 'Active' is noise cancelling and built-in amp turned on. 'Passive' has them turned off.

I have the Sennheiser PX210BT which doesn't have noise cancelling of any kind. The Active/Passive impedance is 590/100 ohm. Therefore I think Active simply means 'using the built in amp' and passive means using the headphone cord to connect directly to the device with the internal amp turned off. I just can't figure out why impedance would jump up to 590 ohm for active mode. What does that number mean and how is it useful to me?