Break-In is Brutal

Purchased midrange Morrow interconnects, speaker and sub cables over about a 6 month period and breaking them in has been ongoing for a while. Got the interconnects for DAC, preamp and amp first- much improved after 200 hours, awesome after 300.The speaker and subwoofer cables have seemed to settle in a bit quicker.. Morrow’s up front about break in and they were certainly correct. I realized break in is a thing when I started using some tube gear some years ago.

Legit places should have cook the cables for you to reduce such break in.   Especially if such makers have every good intention for you to audition the cables during the "in-home" trial period.

While I don't dispute the effect / necessity of break-in, a bad cable will sound bad no matter how much break-in you give.   An new BWM won't drive like an Yugo during it's first 200-500 hours, just saying.

I'm rigging up a burn in cable for my new tone arm (wires) which is just the cost of parts. I'll run some CDs through it. The Hagerman Fry-Baby (or whatever it is called) may be worth the two hundred bucks for cable burn in if it is an issue- (I don't own one so can't speak to whether it has shortcomings compared to the more expensive Cable Cooker, which seems to be the more popular choice among the cognoscenti).
 I used to burn in power cables by connecting them to a power strip with an IEC connector and sticking a fan on one of the outlets to draw power. 
I was never much for specialty burn in but just did it as the system played. With the tone arm wire, though, my thinking is that the low voltages normally produced by a cartridge will take forever. 
FWIW, which may be very little. 

The connectors I think are particularly brutal.

getting NEMA to IEC adapters is a MUST for 'philes.

fans are good. so are freezers and refridgerators, they don't provide constant current draws and for no good reason I think fluctuating current is a better way to break in PCs as that is what they will experience 'on the job'.
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ICs and spkr wires, its nearly a must to have a secondary or even a third outfit to hang them on rather than to sap up tube life, or life in general off the main rig.

as such, I love HT receivers!!

there has been near constant talk on this subject here for decades. I'd do some searching on cable burn in and see those threads that mention dIY burn in units for IC and or speaker wires.

in fact I've always thought someone ought to build some and rent them out! or Charge for their use.

google it!!