I have a VAC 70/70... and like you, my lights dim when my A/C turns on. I use dedicated 20 amp outlets. I gave up on power conditioners years ago.
Ok to use a Shunyata Hydra A-4 with a VAC 70/70?
I have a VAC Renaissance 70/70 amp and VAC Renaissance MK II preamp. I have been advised to get a power conditioner since the lights in my house dim every time the A/C and furnace go on, and I am considering getting a Shuntata Hydra A-4. Any problem plugging the VACs into the Hydra?