No, I've not tried the Zero. I mostly go for try before you buy on headphone amps, as I've tried very expensive ones that don't offer a massive improvement.
For example, my £100 Mackie mixer is nearly on par with a musical fidelity X-Can V3 for my HD600s or DR770 pros. Both of them are a nice improvement over my AV receiver's headphone out, my CMOY or E5. Both of them don't help the NS1000s in passive mode much at all though, where the CMOY and FiiO do the best job.
The NS1000s behave very strangely when it comes to amplification, compared to all other headphones I've tried with different amps.
For example, my £100 Mackie mixer is nearly on par with a musical fidelity X-Can V3 for my HD600s or DR770 pros. Both of them are a nice improvement over my AV receiver's headphone out, my CMOY or E5. Both of them don't help the NS1000s in passive mode much at all though, where the CMOY and FiiO do the best job.
The NS1000s behave very strangely when it comes to amplification, compared to all other headphones I've tried with different amps.