Upgrade your tape deck standard power cord to an "audiophile type". It's mandatory. I'm using DH Labs Power Plus Reference with great connectors. My tape deck is an Otari MX-5050 with Bottlehead's Eros tape preamp and tape path upgrade.
Maybe a Bottlehead power cord? They have improved my Foreplay and Eros. Next will be my Paramours. I'm set up for them but I have to drill a square hole in the bases for the IEC connector.