adding an "on" lamp to amp kit

[jayw404]

Hello,

I have purcased a mono tube amp from www.s5electronics.com. I am building my own enlcosure and would like to add a lamp inside to illuminate the front panel I am having laser cut. How do I add a lamp that will come on when the unit is powered up?


Thank you,

Jayw404

[HollowState]

Jay, I assume you mean what's called a pilot light to indicate the amp is powered on. The easiest way for you to do this is to visit your local electronic store (like Radio Shack) and purchase an LED style light assembly. Get the type that will operate on 117 volts and connect it across the power transformer primary after the on/off switch. (The black wires as shown in the website picture.) R-S has several sizes and colors to pick from. Of course you'll need to drill a hole to mount the light.

[arnoldc]

There is also a power switch that has built in light that you ca get from RS Components/Farnell. The round one is what I use in one of my amp.

[soundbrigade]

I have tested a nice trick that only works of the tubes are all glass (no metal socket) and there's a hole in the tube socket - I simply mount a BLUE LED on the socket and let it illuminate the tube from beneath.
Tybe-DIYers don't like blue LEDs but I think it is flashy

Another cool trick is to use rather biggish feet for the chassis made up by clear plastic and have blue LEDs illuminate them.


Here's a 6550 with a yellow LED:


6BM8 witha blue led (too much ambient light):


GU50 with blue LEDs:


For the LEDs, I tap the heater voltage, using a 1N4007 diode to rectify and a resistor to adjust current through the LED.

[arnoldc]

Hi Magnus, no noise introduced on the filaments?

[soundbrigade]

To be honest - I don't know. Or maybe my good ole ears don't hear it.

Much of my projects are based on the principle "Good is good enough".
But it is easy to verify. Just in case you could hook up a cap to kill possible spikes generated from the diod and LED.

[arnoldc]

I'll try it on my headphone amp