Ringing new NOS tube, is it safe?

Dear all,
Need some advices.
I bought NOS 12AX7 tubes from a reputable source (never saw any complaint about the seller) about 3 months ago for my phono preamp.

However, I start hearing ringing sound/noise from the tubes (not from the speakers). Is it safe to keep using it by dampening it with tube damper?
Is it possible that there is something wrong with the preamp circuit that might cause the ringing tube?

Thanks in advance for the advice

Showing 1 response by ebm

The tubes are crap you got taken!!Try Vintage Tube Services one of the few honest venders.