One of the pair of Audio Innovations 1st Audio monoblocks I bought makes quite a whoosh on power up through the speakers. This is.a new development. I’ve swapped the valves between the pair and it makes no change. I’ve opened it up and it’s all very clean and tidy. No obvious signs of bulging or leaking caps no brown resistors. The 220uf 400v. caps look to be the same brand I swapped out from my Audio Innovations 500 that I’ve owned from new. Any ideas where I should start looking? I’m not competent enough to poke around with them plugged in but more than capable of swapping out a few parts a day or so after any caps have discharged. Couple of valves are a bit wobbly but it looks like the contacts moving inside the base not bad connections.