I've got a setup that consists of an Audio Technica LP60-USB turnable, into a Schitt Mani 2 preamp, and into a Yamaha RX-V4A home theater amp.
The amp is indeed overkill for the scenario, but it was our home theater amp for our last home. We moved and downsized to a soundbar, but I decided to keep the amp it and move it to my office for music.
I decided to add the Mani 2 to improve the sound quality a couple months back, and it's been a phenomenal addition. However, since adding that, once the amp is on for 10-15 minutes or so, it starts making a hum, like something is unplugged. It only happens on the phono setting, so it's not other inputs.
The hum goes away when the RCA plugs are unplugged from the Mani 2, but if I plug in something else (like my cassette player to it, for example), it comes back. That led me to think it has something to do with the Mani 2 and something that kicks in on it from input sensing.
I contacted Schitt and they thought it might be some sort of power issue. However, I found that if I move the record player (which sits on top of the amp), the buzzing eases up.
So it seems like there is input sensing on the Mani 2, but the power in the LP60 introduces hum into the amp, but only on that setting.
I really don't have another place to put the LP60 or the amp. I might just have to deal. Anyone have any suggestions on any other things I can do?