So I got a crate blue voodoo 120 in a trade.

It has those silly lights in the back behind the power tubes. I want to switch out those little flashlight bulbs for blue LED's. Do I need to throw a resistor in so they don't fry? I have some electronics background but am kind of scared of tube amps cause I know the caps are dangerous and whatnot and I also don't want to permanently damage anything on the amp.

second question. I want to replace the little on/off and standby switches with something cooler looking. Do I need something that's rated at exactly the same voltage and amperage as the stock switches? I know this sounds like a dumb question but again, I'd rather not screw up this amp by trying to make it look cool.

__________________
Gold hardware should be OUTLAWED!!!

The LEDs don't need as much current to operate as an incandescent lamp. What's the potential across the lamp socket when nothing is plugged in? Choose your resistor to put in series with the LED based on the forward voltage/current rating of the LED. For example if my LED is 3.5V @ 30 mA (that's a pretty typical, bright blue LED spec) and the potential across those sockets is 12V I'd need a 300 Ohm 1/2W resistor to light up the LED.

Here's a handy calculator:

http://led.linear1.org/1led.wiz

The same or higher and you're safe.

__________________
- IAN C. -
Rig: PRS | Schecter USA | Gibson | Axe-Fx II | empress effects
Beta tester: Fractal Audio | empress effects

I would seriously look at a schematic before you start messing with those internal lamps. Some amplifier circuits use lamps as current limiters or as a substitute for varistors. I don't have the schematic in front of me so I just don't know. If they are just lamps paralleled up on a power supply rail, putting in LEDs with the correct load resistor won't matter. If the lamps are incorporated in the output amp circuit, they have a function and putting in LEDs could be catastrophic since they are diodes with much different functional characteristics than lamps.

__________________
Stage Guitars: '80s Thin line LP Custom, '70 LP Standard, '83 Squier Black Headstock Strat w/ Dan Torres pickups, '59 Black Danelectro DC, sometimes others.

Pedal Board: Nady UHF 10 -> TU2 -> Rocktron Big Crush -> 70s MXR Phase 100 -> Cry Baby -> Bad Monkey -> Early '80s Rat -> Early '80s Ibanez CS 9 -> Ibanez DE 7 -> Behringer Dr 100 Stereo Reverb

Stage amps: '63 Blonde Tremolux w/ two original 2X10 cabinets with a '60 Ampeg Rocket/18 watt VTB Marshall clone/ Epi VJ into a Mashall 1965A

Right, olddawg. That's exactly what I thought after my first run.

So I put in four blue 5mm LED's in place of the sockets and turned it on...they work, but some are flashing rapidly. And then start flashing slower and slower until they go out. Now, only one is still operational. Of course, this is probably because I didn't put any resistor on it, but who knows, maybe I should put the lamps back in. I couldn't find a schematic anywhere online since this isn't one of those amps that people do a whole lot of stuff to.

On another note. In replacing my switch, I messed up which wires go where and have blown some fuses in the amp and also screwed up the wall sockets in my garage. Could someone tell me how the switch is supposed to be wired correctly? I've got two blacks and a white hooked up to a spst switch. Do I just need a dpdt or is there something special about the stock switch (little rocker type with internal light)?

__________________
Gold hardware should be OUTLAWED!!!