Bose QuietComfort 35 II Review (Noise Cancelling Headphone)

[mjnichol]

Using that would require passive operation since the active noise cancelling is an amp unto itself, right?

And these don’t sound very good when in passive mode.

I'm using an amp with these and have the headphones in "on" mode. The amp works as expected (need to turn the Topping DX1 to about 75% in "low" mode to get a nice loud sound) and the noise cancellation still works as expected. I don't think the headphones are really amplifying the incoming sound much.

They actually sound quite impressive this way without the bluetooth sound compression, especially with HiRes audio.

 

[solderdude]

Using it wired in on-mode is not the same as passive (off-mode).
In off-mode (so no NC and or when the battery is depleted) so in passive mode you can still use it but the sound quality and seal response is quite (very audible) different.
This is what nathan was talking about.

In active mode the input is 480ohm, in passive mode 40ohm and has a higher sensitivity (118dB/V)
No headphone out will have issues with driving 480ohm where sensitivity is 115dB/V

passive vs active (wired)

Different seal in passive mode:

same seal changes but in active mode:

 

[mjnichol]

Using it wired in on-mode is not the same as passive (off-mode).
In off-mode (so no NC and or when the battery is depleted) so in passive mode you can still use it but the sound quality and seal response is quite (very audible) different.
This is what nathan was talking about.

In active mode the input is 480ohm, in passive mode 40ohm and has a higher sensitivity (118dB/V)
No headphone out will have issues with driving 480ohm where sensitivity is 115dB/V

passive vs active (wired)

Different seal in passive mode:

same seal changes but in active mode:

Thanks for clarifying. Maybe I misunderstood what a balanced cable is and why it can't be used in active mode.

 

[solderdude]

Maybe I misunderstood what a balanced cable is and why it can't be used in active mode.

The QC35-II can not be used with balanced cable/gear. The Bose is single ended only (3.5mm TRS cable)

 

[nathan]

Using it wired in on-mode is not the same as passive (off-mode).
In off-mode (so no NC and or when the battery is depleted) so in passive mode you can still use it but the sound quality and seal response is quite (very audible) different.
This is what nathan was talking about.

In active mode the input is 480ohm, in passive mode 40ohm and has a higher sensitivity (118dB/V)
No headphone out will have issues with driving 480ohm where sensitivity is 115dB/V

passive vs active (wired)

Different seal in passive mode:

same seal changes but in active mode:

This is a really useful post.

My original response was intended more as a leading question than a definitive statement.

Based on this measurement and @mjnichol description I think wired (singled ended cable) and powered on would be a good way to use them. I sold my pair so I cannot try it.