<div>Yes, the high-pitched beep is likely due to a ground loop caused by the T-1 being powered via USB from your Mac M1. Ground loops are a common issue when connecting USB-powered devices to audio gear, especially when they share different grounding paths.
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<div>Your fix—powering the T-1 from a separate USB power supply instead of the Mac—works because it prevents the unwanted ground current flow.
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<div>Other potential solutions:</div>
<div>•Use a ground loop isolator between the T-1 and Pulsar-23.</div>
<div>•Ensure all gear is powered from the same source (same power strip) to minimize ground differentials.</div>