"Hot plugging" how harmfull is it?

[Lo-Fi Mike]

hello, i'm a little worried about my new tube microphone can you help please!!

Before opening the mic up i read the whole manual, and i read about a thing called "hot plugging" (plugging the mic into an energized power supply).

so i carefully set everything up in the right order, and was very carfull pluggin in the 7 pin cable, when i went to turn on the external power supply (as my final step) i realized that it had been on the whole time!!
yes, yes i just "hot plugged" a brand new $1000.00 tube mic.

so here is my question-- how much trouble am i in, will i notice a differance in the sound, or is this somthing you have to do a couple of times to actually do harm anything?

thank you for all your time an expeareance helping out folks like me!!

 

[MichaelJoly]

It depends on the circuit of the mic.

I trashed the first 5840 tube in the "Royer mod" tube mic I built from scratch. Like you, I inadvertently pluged the mic into the power supply while the supply was on. Problem is, like a light bulb that blows out when you turn it on, the filiment in a vacuum tube has a very low cold resistance compared to when it is hot. This means a lot of current can flow though the filiment and burn it out. The Royer power supply circuit does not prevent this from occuring.

Your mic might possibly have current limiting protection for the heater or a "soft start" circuit desgined to gradualy bring up the voltage across the heater to limit in-rush current flow. Of course, this only protects the cold heater of a mic that is already connected before the power is switched on. Once the power is switched on for more than a couple of seconds, full current is made available to the heater. A cold heater encountering a charged power supply is not going to be happy.

Other than possibly destroying the vacuum tube, the mic is probably OK.

 

[Lo-Fi Mike]

thats wierd the vacuum tube in my mic is a 5840 aswell. the mic i have is the new mojave audio ma-200 by royer
but the mic is working so i guess i have nothing to worry about. it was just bad for me cause this was the first time i opened it up, and had never before touched a tube mic. so i could not tell if the sound was different, since i had nothing to compare it to.
if i had blown it, is it just a matter of replacing the tube?
thanks again for all your help!!