Given the choices, if cost affordable, that NAD M33 looks very desirable (for your young digital loving crowd). 7" lcd control panel, features galore, high quality, slots for future technology.
200 wpc into either 8 or 4 ohm loads is very nice, plenty of power for the majority of speakers.
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MINIMUM watts per channel needed is the most important factor regarding speaker damage, too little can harm speakers. The speaker’s sensitivity determines that, see below.
MAXIMUM watts per channel is not meaningless, but is essentially meaningless, you could but wont burn out a speaker with too much power (except by intention while wearing earplugs). Yes, some drunken teenagers could blow a tweeter, but .....
PROTECTION: NAD still has protective circuitry doesn’t it? I seem to remember NAD’s initial claim to fame in early 70’s was it’s ’soft clipping’ protection. That allowed the safe use of borderline low powered amps, physically smaller than otherwise needed. McIntosh amps have protection built in, other brands must also, read the specs.
ENOUGH watts per channel is important, for Instantaneous power for needed surges of volume (any frequency) in the music, and if trying to produce a lot of bass: lots of continuous power is needed. Buying more power now gives flexibility when considering alternate speakers in the future.
SENSITIVITY (efficiency) (how loud compared to other speakers?)
Standard measurement to establish a COMPARABLE # is a mic 1 meter away, a 1 watt signal sent to the speaker. What sound level in decibels (db) produced by THAT speaker? ____ db? That is the primary fact you want to know about a speaker when choosing MINIMUM NEEDED wpc. Those JBL 830’s Sensitivity is 90db, placing them in the average sensitivity category.
meaning: measured 1 meter away, given only 1 watt of power, they produce 90db sound level.
A less sensitive speaker, say 87db rating, would need more power to produce an equally loud 90db.
https://www.psaudio.com/article/how-much-power-do-i-need/ excerpt
"Basically, you need one hundred times more power to get another 20dB in sound pressure. That means if it took one Watt to make 90dB, it’ll take one hundred watts to make 110dB (and 115dB is as loud as a rock concert)."
a bit more here
https://www.musiciansfriend.com/thehub/understanding-wattage-speaker-efficiency-amplifier-loudness