LEDs for tube pedal

[horn man]

I'm getting ready to build a hot box and want to use LED's to indicate which channel is engaged and also for true bypass.  From this layout, www.generalguitargadgets.com/diagrams/hotboxsc.gif true bypass isn't shown nor channel indicators, as far as I can tell.  I'm assuming that using #44 AC bulbs running off the heater supply could cause hum.  If I want to use the heater supply to power LED's instead would I use a single diode to rectify voltage for the LED's and one resistor each for the LED's?  What value for the resistors? (and I realize I would use a 3PDT for bypass and 4PDT for channel switching).

[Johan]

since there are no switching shown for the lamp's, I would assume they are there only to keep things looking cosy...but I would also prefere lightbulbs for indication over LEDs on an AC powersupply. LEDs can cause a sertain kind of noise that gets very difficult to filter out
j

[horn man]

But would running 6.3 volt AC to the 3PDT and 4PDT cause any problems with the signal lines, with shielding, of course?