Noise from Uptone Audio UltraCap LPS-1 and PP15

Strange issue, and curious if anyone else has ever experienced this. I just recently bought a used Uptone Audio LPS-1 power supply, and as many know it has 3 voltage settings on the back of the chassis. When plugged into my PS Audio PP15, and set to 7v, there is an annoying, high pitched buzzing that comes from the LPS-1. When set to 5v or 3.3v, it is dead silent.

Here comes the strange part. When plugged into the wall socket, and not the PowerPlant 15, the LPS-1 is dead silent at all voltage settings, even the 7v setting…so it definitely seems to be a PP issue. I tried the clean function on the PP, as well as switching from MW to Sine, with zero changes.

Has anyone seen this issue?

Give Alex Krespi at Uptone a call.

I run mine at 7.5V with no issues.