Value of burn/break in?

I'm breaking in two new things...a Pangea wall plug and a new belt for my Linn table. The wall plug's most important job is to power a REL sub, which it did right off the bat with zero break-in. Amazing. The Linn belt also seems to accomplish the task of making the platter go around also with zero break-in, which makes me suspicious of both these items...were they used previously? Hmmm...

When I bought Cary Audio SLP 05 preamp, it sounded horrible out of the box. Billy Wright of Cary Audio told me to leave the preamp on with amps off and play something like a radio through the preamp continuously for 50-75 hours (Friday through Sunday). It made rather dramatic change which continued for next week or so with usual listening sessions. I don’t know if that will breakin the wires (interconnects might be but not speaker wire). 
Good listening!

I purchased an entry level tube pre 2 years ago , a Rogue RP-1. After two weeks I changed the 2 12AU7’s and after 4 or 5 pairs, settled on Telefunkens . Then I auditioned 3 different power cords that are under $125 ea . Both made a huge difference . But the greatest improvement was dumping the JJ tubes . I tried all NOS pairs and every single pair trounced the JJ’s . So what Pre do you have and what tubes did it come with ? You’ll be pleasantly surprised with the change . Also keep the other tubes that you buy while experimenting  for when you change components, cables or move your speakers . I’ve gone back and switched to adjust for system changes. Happy Listening , Mike.

I use Tubes and a CD spinner--about 1t/2 hours before serious sit down 

listening I run the Cardas Sweep/Tones/noise tracks on repeat at

moderate volume.

The system is ready for virtual instant Kharma after that with my

selection.

My technique anyway

T212

I have found 3 levels/processes of burn-in that operate in audio systems. Each is real (judging by subtle but perceptible sonic results) and has its own time requirements:

1 - New electronics:: Solid state electronics as well as individual tubes benefit greatly from burn-in when new. My nominal/minimum burn-in time for any new component is 100 hours. BTW, burn-in for certain purely SS pieces can be much longer. For example, my two Audio GD multi-bit DACs (NOS 19 & DAC-19) each required ~400 hours before the sound stopped changing and stabilized. Other owners of these DACs had warned me of this extensive burn-in requirement...they were right.

2 -  New speakers/headphones: These need ~100 hrs initial burn-in.

3 - Initial turn-on of system: As others have mentioned, SS units (ones that have already had initial burn-in) benefit from simple warm-up when first turned on (usually 15"-30" does the trick) and can be left on 24/7, particularly line-level components (vs amplifiers). I've also found that certain tubes require ~30" initial warm-up before sounding their best.