must you play music to break in tubes

only time I've seen a crackling sound being normal was when small bits of particles get trapped in the tubes plates during construction/shipping, a hard tap with the back end (handle end) of a screwdriver can dislodge the particles and return to normal operation. If its not that its a a bad tube from my experience. 

+ return 

You can turn the volume down while waiting for the noise to clear.  If it is what glennewdick described, it doesn't take that long to clear up.  The particles will burn up and the problems stop.  I hear that crackling rustling noise very rarely, and it is this issue of flakes falling on the cathode.  In my case, it is an amplifier tube, so I just have to endure the noise until it stops.  That usually takes a few minutes.  This happens with my very old set of tubes once in a great while (in the past 10 years or so, it has happened maybe four times).

I've owned tube amps since the mid 60s, and I will never stand for even a moment of any crackling sound. Others may tolerate that sort of thing, or think up silly explanations based on nonsense to explain it (flakes falling on the cathode? really?), but tubes should sound fresh and noiseless or they will not be used in any of my hifi or guitar amps. I've had preamp tubes (new or vintage NOS) last far longer than predicted by so called "experts" and have had others basically explode immediately...ya never know, but the damn things are generally trouble free for their life span, and any noise gets 'em tossed.

My tubes are dead quiet except for those rare instances I mentioned above.  Get rid of them just for these minor sins--they have worked well for me for a very long time even though they were old and used tubes (tested strong) when I got the amp.  They are also nearly impossible to replace.  The last time I saw these tubes offered for sale, they were of unknown condition AND they cost $2,000 each.  

those sellers really rely on audiophile deity about break-in process. I'm glad that such deity had been debunked and seller is at least getting confronted with return of "NOS tubes that need break-in to stop crackles"