Using heater rail to power two leds

[My3gger]

Hi,

i'm finishing another tube preamp and can only get psu board with HT, heater and phantom rails (it seems like no one sells one with HT, heater, phantom and utility).  As there are two red leds to power i thought about using utility rail, but as board doesn't have it i could use heater rail to power them.
Do you see any problems with that? I already did it and couldn't notice any problems, but i didn't really measure things at a time. I'm afraid leds could induce noise into heaters, otherwise i have more than enough heater current and of course know how to calculate current limiting resistor.
Yes, i could make simple p2p utility (amp part is p2p) rail, but as i'm doing this for exam i would like to have psu on pcb. This way it will look cleaner and i have one more reason to "defend" my p2p amp (simple for one off, easy to modify, good cooling..) 

 

[PRR]

AC or DC heat?

With DC, the noise is zero.

With AC, there are harmonics of 50/60Hz so you don't want LED wires around your inputs.

 

[My3gger]

They are DC powered. Good question, i didn't even think about powering it with AC, and by searching found it interesting for other purposes. Like long strip-lighting, advantages are explained here:  http://ledsmagazine.com/features/3/5/2
I found amp has some high frequency deviation when i use input transformer's secondary wires shielded. It's not too bad, but i will see if it can get any better without making leads much shorter. I'm surprised manufacturers are still making input transformers with leads, when we can choose any wire for pcb versions. Maybe it's so because of aesthetics, i don't have pcb mount input transformer at hand to measure it.