I saw this in another thread:
Source: http://www.head-fi.org/t/410326/for-6as7g-tube-rollers-here/3510#post_12514342
Should I be concerned? Could using the EL3Ns damage the amp over time?
Hi KP....glad to see you're delighted with your Elise - the sound can only get even better!!
As UT says, the EL3Ns have now been running in a good few amps for quite a while now - mine for many hundreds of hours - and nothing untoward whatsoever...so NO WORRIES!
As for the sound quality, once more I repeat the VAST MAJORITY of users agree with UT's (and my own!) findings. I am quite sure you will also be very pleased with them...unless you're extremely unlucky LOL!!