I'm confident that if Lamm understood the issue as described they would not say it is normal. Feel free to PM me their e-mail reply, don't post it in this thread.
Is your unit new or used?
How old is it?
When did the 'noise' appear?
Does the noise occur with both MC and MM inputs or just one of those?
When was the last time you changed tubes?
Since a tube change is less cost and effort than a repair, I suggest swapping in a new 6x4 rectifier tube in the power supply. That can be a 6X4W, 6X4WA, 6202, EZ90, CV4005, CV493. Maybe that will help, maybe not.
View attachment 122276
The LP2.1 is a
very quiet phonostage.