I rolled tubes and I got hum

I just rolled the two 12AU7 tubes in my Bottlehead II pre with a pair of suppose NOS Telefunkens and right away I heard some noise (hum) coming out from the speakers. The hum can be heard at a distance of about one foot from the speakers, is not very loud and does not increases by turning up the volume. Any idea about what´s going on? With the others tubes (Electroharmonix) the speakers (i.e. the pre) was dead silent.
Well the new tubes have been playing for 7 hours and one channel lower the hum considerably. I hope as time goes by the tubes will stop making noise.
I ran into the same thing. In my case it was poor contacts due to loose pin to socket contact. I would also check if the tube pins are clean.
Could be due to a greater amount of heater-to-cathode leakage in the new tubes, interacting with whatever amount of AC ripple may be present on the voltage that is provided by the preamp to the tube filaments/heaters. I once experienced that issue, with different equipment.

If you have or know someone who has a good tube tester, such as a vintage Hickok, you could measure that leakage and see how much it differs between the various tubes.

If that is the cause of the problem, as far as I know it could continue to improve, or stay the same, or get worse over time, with little or no predictability.

Also, it might be worthwhile interchanging the two new tubes between the two positions in the preamp, unless you have reason to believe that the circuit applications in which the two tubes are used are identical.

-- Al