I have several on the circuit with my PC and it looks like a Star Wars battle scene. Some major flashing. Also have one on the circuit with my router. It is hard to test if or what these do for the sound since there are two floors between the source and the PWD.
EDIT: meaning my legs aren’t what they used to be…
Short report:
My two harvesters arrived just yesterday.
One plugged into PC circuit, other into audio circuit.
They are only very seldom flashing (like once per 30-60 seconds) until I turn on the dimable light - then they start flashing every 1-2 seconds. Will experiment with different placement of both and also different periods of day . Also I have not yet focused on change in audio SQ, but will soon (hopefully this weekend 
)
Yes, well in my order I recently got I received 4 for me 2 for my brother-in-law.
He has some serious over voltage issues by the electricity provider in his area and until I convince him to buy a power regenerator, his system suffers. Any way, he was raving about the two little black beauties I handed him. I have to admit it made a very nice difference in his system, though it most certainly hasn’t fixed everything yet.
He has a Quintet so I told him what I’ve said here, don’t just plug’em in (which is all he did) - experiment with different combos in the Quintet (and elsewhere on the line) to see which kit responds to being ‘harvested’.
Right now (and my system is above so people can see) I have three in the Dectet zone that has my spinner, one paired on the same outlet as my tube buffer, one in the back of the pre-amp and one in the wall of my PPP which powers the whole shebang.
With all the flashing at night it looks like I have some COM-PUTE-TOR from a bad 70’s Sci-Fi movie behind the system, busily ciphering & bleeping away - no doubt working on a way to tell me I should getting my own regenerator perhaps.
But that’s what seems to work best for me…