Cambridge Audio CXNv2/CXA81 - best way to connect a headphone amp


Novice Member

I am wondering if there are any owners of this setup who could offer advice on the best way to attach a headphone amp to the system? My only source is the CXNv2. I currently have a Bottlehead Crack valve headphone amp connected to the line outs of the CXN but don't know if this is the best option or to attach the Crack to the CXA81? It sounds okay but I was hearing some distortion creep in on certain tracks when listening on my headphones (Sennheiser 650s).

I've read that the CXN can be placed in pre-amp mode but not sure if this is required or would then affect the signal that is being sent to the CXA81 for when I want to listen via speakers? I connect the CXA81 to the CXN via the balanced XLR's

Any guidance would be much appreciated.


BT Bob

Distinguished Member
Can you not use the headphone out on the CXA81?

I have the 61 and the headphone amp is very good, so I assume the 81 would be good as well.


Novice Member
Thanks for your reply Bob,

I did check the headphone out on the CXA81 and it is good but the Crack amplifier adds some warmth/musicality to the sound that I personally really like. I had also contacted Cambridge themselves to ask the question and I am posting the response here from Alex in tech support incase anyone else has the query......

Essentially, if connecting the headphone amplifier to the line out on the CXN (V2), the DAC (or digital to analogue converter) will convert the signal internally within the CXN (V2), then send that converted analogue signal to your headphone amplifier via the line output.

If you were instead to connect the headphone amplifier to the Pre Out on the CXA81, and ensure that the CXN (V2) is connected digitally to the CXA81, the DAC in the CXA81 would instead process the digital signal from your CXN (V2).

The digital signal would then bypass the DAC in the CXN (V2), and instead be processed by the DAC in the CXA81 which is preferable as the DAC is slightly improved.

So really your headphone amplifier would then just take a slightly improved converted signal from the CXA81.

..... I then had some further correspondence regarding controlling the volume .....

Yes, I would suggest a Digital Coaxial connection between the CXN (V2) and the CXA81. I would suggest connecting other sources such as your TV to the CXN (V2) and then sending that digital signal on to your CXA81 to be processed.

If you connect the headphone amplifier to the pre-out, the CXA81 will act as a pre-amplifier. In practice, you will be able to adjust the volume from both the CXA81 and the headphone amp. This configuration can be very convenient when your headphone amplifier does not have a remote control, as you can then easily control the volume remotely with the CXA81 remote control.

However, care must be taken to keep the output level close to that accepted by the headphone amplifier’s input so as not to generate distortion.

You will still sound from the speakers and won't be able to switch between the outputs so to speak, so this may not be ideal if you plan on using the speakers and headphones individually. So if this is the case, you may well be best keeping the headphone amplifier connected to the line output on the CXN (V2), but this will of course mean that the digital signal is processed by the CXN (V2) instead of the superior CXA81 DAC.

So full marks to Cambridge for getting back to me with a detailed response. I've got a Digital Co-ax cable on order and then I'll compare the 2 DACs and go from there.


Standard Member
I’m a little late to this discussion, but here is my opinion and what I have done. I picked up a set of Schiit Pyst XLR cables to connect the CXNv2 to the CXA81 via XLR. I connect RCA out from the CXNv2 to my headphone amp (DarkVoice tube amp or Aune X7S. Setting the CXNv2 to pre-amp allows for remote control ov volume, but I leave it at fixed output to my amps and control volume from the headphone amps.

It’s a matter of opinion, but I don’t think the CXA81 DAC is better than the DACs in the CXNv2. They are both good, but I prefer the CXNv2 DACs. If you are not going to use the DACs in a CXNv2 you have severely overpaid for a streamer. IMO.

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