Unless you’re performing an experiment of some kind, there’s no reason not to.
If you’re new to tubes then you’re likely to hear some things that’ll surprise or even worry you at first.
It’s not at all uncommon to get whistles and low-frequency warbles during the first few hours of using a tube and, especially, in the first few minutes after power on each time you listen (though the duration of that will rapidly abate).
Tubes are microphonic, in general, and as things expand/contract, as they will over several minutes to maybe half an hour initially, so you can expect to hear metallic “tink” and “ping” sounds. You can often hear these noises directly from the tube too (i.e. not via the amp/headphones … just ambiently). And they’ll go away progressively faster over time.
With very low-impedance cans, say TH-X00, you’ll hear noise at power-on, and it’ll drop in level over a few minutes of warm-up. How quickly it goes away, and it’s peak level at power-on, will generally drop as well as you get more time on the stock tube.
Finally, exposed tubes are quite susceptible to EMI/RFI. If you hear the classic “helicopter blades” sound, then you likely have your cellphone too close to amplifier. Not really an issue with the MCTH … as half of the tube is buried in the case and most of the top is silvered.
The bigger the tube, the more of them, the purer the circuit (i.e. pure tube designs exhibit these traits more than hybrids), the more pronounced these sorts of things will be. With a little tube like the 6922 they’re pretty minor and go away quickly.