Mullards for Preamp?

I have a Cary SLP-74 tube preamp and just replaced the original Chinese tubes with Mullards. When I turn the preamp on to standby the two output Mullards flare up and then go down. Is this normal? They really sound amazing as compared to the ones that came with it. Very warm and lush sound. Just what I wanted. I just need to know if they are supposed to do the flare up thing? Thanks for any help. -Durr
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Yes, The flash is normal, don't worry about it, they are suppose to do that.
Enjoy, great tubes.
This is normal for some Mullards and other tubes. I wouldn't worry about it.
Exactly right you don't always see the flash, but the sound you are getting is what is intended. It's the British sound type people are generally referring to. That's why there is a high demand for those tubes.
Do all mini tubes (6DJ8, ecc82...) manufactured by Mullard flash, regardless of brand? For example, would a Philips tube manufactured by Mullard in either the Blackburn or Mitchum plant exhibit the flash, due to the same construction? Or, are Mullard branded tubes constructed differently than Philips branded tubes manufactured by Mullard...even if both tubes are made in the same plant?