I use Chord Qutest with "white" filter.
It sounds natural, not cold or harsh.
But I use 300B SET amplifier that typically sounds smooth and warm.
Here are some videos:
https://youtu.be/e_fpf8TivMA
https://youtu.be/K3aMCNAD3C8
https://youtu.be/mpozf8b8COE
https://youtu.be/lpxmcFxcTxA
https://youtu.be/KK6r29u3bs8
It sounds natural, not cold or harsh.
But I use 300B SET amplifier that typically sounds smooth and warm.
Here are some videos:
https://youtu.be/e_fpf8TivMA
https://youtu.be/K3aMCNAD3C8
https://youtu.be/mpozf8b8COE
https://youtu.be/lpxmcFxcTxA
https://youtu.be/KK6r29u3bs8