#1
I want to mod a tube amp so the tubes are backlit. I've seen this done on several amps such as Hughes & Kettener. The purpose is all aesthetic so I was wondering how to do this. Has anyone done this before? I don't want cathodes, I want the tubes to glow either green or red. I thought about getting a three colored led and tie it into to the channel switching.

You can see in this picture how there are red leds along the back of the chassis. I have seen other amps that placed them directly behind the power tubes making the glow like mad.

How would I wire this? Would I want to use a separate power supply or could I use the amps? I have never worked with leds but have tons of experience in guitar wiring and amp repair. If you could whip together a schematic it would be awesome. I have never done this before any help is appreciated.
#2
You mean like this?

I'm using ultraviolet LEDs under the tubes. You can connect LEDs to your tubes' heater power. If the heater circuit is AC, you don't have to worry about the LED polarity. Just make sure you use the correct resistor for the voltage. About a 470 ohm resistor for each LED will work for a 6.3 volt heater supply.

Wikipedia on LEDs: http://en.wikipedia.org/wiki/Light-emitting_diode

As far as wiring, all you do is connect a resistor in series with the LED, then connect the LED across the heater power supply.

It would help if you let us know what brand and model amp you're planning on modding.
#3
Quote by Losenger
You mean like this?

I'm using ultraviolet LEDs under the tubes. You can connect LEDs to your tubes' heater power. If the heater circuit is AC, you don't have to worry about the LED polarity. Just make sure you use the correct resistor for the voltage. About a 470 ohm resistor for each LED will work for a 6.3 volt heater supply.

Wikipedia on LEDs: http://en.wikipedia.org/wiki/Light-emitting_diode

As far as wiring, all you do is connect a resistor in series with the LED, then connect the LED across the heater power supply.

It would help if you let us know what brand and model amp you're planning on modding.



Yeah that's pretty close. I'm getting a Carvin V3 sometime soon and I plan on doing this mod to it. Those LEDs are UV, same thing as a blacklight, right? Would it work the same if I used a color for more effect? Did you mean place the resistor then the led in the series or the other way around? By underneath, where is the led located? I know the V3 uses board mounted tube sockets not sure if they will fit under, but if placed behind it should work similarly I think.
#4
Yeah, colored LEDs would work the same. Connect the resistor to one of the LED leads first, then connect the other LED lead and the free lead of the resistor to power.

By underneath, I mean I glued the LED to the center of the tube socket, underneath the tube. Play around with the positioning.
#5
DISCLAIMER:

Kid, you're 15 year old. I want to make sure you see your 16th birthday.
This is not like messing around with the guts of a computer.
The voltages in that amp are serious business.
There are capacitors that can hold a charge.
Then when you touch the right terminals of a tube socket,
you'll get knocked on your ass.
It might even kill you.

Learn enough about that amp before sticking your hands inside.
Learn how to safely discharge the capacitors.

Be safe, don't be dead.
Meadows
Quote by Jackal58
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#7
Quote by SomeoneYouKnew
Kid, you're 15 year old. I want to make sure you see your 16th birthday.
This is not like messing around with the guts of a computer.
The voltages in that amp are serious business.
There are capacitors that can hold a charge.
Then when you touch the right terminals of a tube socket,
you'll get knocked on your ass.
It might even kill you.

Learn enough about that amp before sticking your hands inside.
Learn how to safely discharge the capacitors.

Be safe, don't be dead.


Besides maybe the first line, +1.
#8
Quote by SomeoneYouKnew
DISCLAIMER:

Kid, you're 15 year old. I want to make sure you see your 16th birthday.
This is not like messing around with the guts of a computer.
The voltages in that amp are serious business.
There are capacitors that can hold a charge.
Then when you touch the right terminals of a tube socket,
you'll get knocked on your ass.
It might even kill you.

Learn enough about that amp before sticking your hands inside.
Learn how to safely discharge the capacitors.

Be safe, don't be dead.


yep that's right, as i always say, if a 9v capacitor can throw a 5' 10" science teacher from lancashire across a room (about 90-100kg i think) then imagine what a 5, 6 or 700v one will do. And they can hold their charge for days, weeks or months. You'll have to discharge them before you start messing with the insides.
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
#9
Nope, I'm not 15 but I learned stupidity knows no age limits. Good thing to add a disclaimer for anyone who may 'stumble' on to this. I'm experienced but no expert. Voltage is dangerous, period.

I remember messing around with a disposable camera that I had took apart. I purposely shorted on of the capacitors to the ground. It then became an effective stun gun. Point is that electronics can be dangerous.

That being said whether your young, unexperienced, unsure, or just dumb ask for help or just don't do it, when it comes to messing with electronics.
#10
I have one of those disposable camera tasers in my school bag, they aren't really that powerful, working of an AA battery, though it did knock me to the floor after it had been charged for a small while.

Anyway, yeah make sure it's all safe beforehand
#11
Quote by eddiehimself
yep that's right, as i always say, if a 9v capacitor can throw a 5' 10" science teacher from lancashire across a room (about 90-100kg i think) then imagine what a 5, 6 or 700v one will do. And they can hold their charge for days, weeks or months. You'll have to discharge them before you start messing with the insides.


You should be more worried about the value of the capacitor. Besides, high voltage isn't necessary more dangerous than low value.
#12
Quote by mr_hankey
You should be more worried about the value of the capacitor. Besides, high voltage isn't necessary more dangerous than low value.


yes you are right since you can have as many volts as you want but if there is little current it's not really gonna hurt. Did i mention said science teacher is a physics teacher teaching me a-level physics?
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
#14
Quote by Zanon
wear rubber gloves


No, don't put your hands near dangerous electrical circuits at all.

If you're going to be poking around in your amp, you need to know how to safely discharge the caps.
#15
Quote by mr_hankey
No, don't put your hands near dangerous electrical circuits at all.

If you're going to be poking around in your amp, you need to know how to safely discharge the caps.


That's right any idiot knows to lick the shiny stuff before you go poking around.
#16
Quote by mr_hankey
If you're going to be poking around in your amp, you need to know how to safely discharge the caps.

How do you do that? I'm not going to be taking apart my amp or anything, but it'd be nice to know.
Quote by Chaosinborn

Quote by gh0sthack

Didn't Kerry King use MGs at some point?

I think he just endorses them because he likes sacks of money
#17
Quote by PimpedOutSquier
How do you do that? I'm not going to be taking apart my amp or anything, but it'd be nice to know.


The big electrolytic capacitors are the parts which hold the charge, and you discharge them by shorting them. If you do this with a screwdriver or something similar, you'll get a loud bang, big spark, and you might weld the screwdriver to the chassis. It's also pretty bad for the caps themselves. The solution is to short them with a resistor. It discharges them in a less violent and damaging manner. The resistor needs to be of sufficient wattage so it can doesn't burn out. The resistance also needs to be sufficiently big so that it actually makes a difference.

I use 10W 33k cement resistor, to which I soldered two leads with crocodile clips on the ends. I put rubber sleeves on the crocodile clips and heatshrink on all exposed metal.

When you've discharged the caps, measure the DC voltage across them to make sure it is safe. Anything less than 10v is considered discharged.

Read more here: http://studentweb.eku.edu/justin_holton/caps.html

WARNING: Do not attempt this unless you have a multimeter with which you can check that the caps are actually discharged. You also need to know enough about amps so you can identify where and how the shorting needs to be done. It should go without saying that the amp is unplugged while you have it open; and that the whole process of discharging will have to be repeated if you've plugged the amp in.
#18
Quote by Zanon
wear rubber gloves


any electrical curcit with the energy to get through your skin all the way to your heart will have no problem getting through a thin bit of rubber.
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
#19
Quote by eddiehimself
any electrical curcit with the energy to get through your skin all the way to your heart will have no problem getting through a thin bit of rubber.


Actually, no. Rubber is a pretty good insulator for a lot of reasons.
And those disposable camera flash circuits are nasty things. Hooked up a few of the caps in parallel, then shocked somebody on the ankle when he had passed out from booze He thought somebody had shot him in the ankle.
Oh, don't do it to drunk people He actually ended up with minor burns on his ankle from the terminals.
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."
#20
Quote by the_random_hero
Actually, no. Rubber is a pretty good insulator for a lot of reasons.


Real rubber, that is. The 'rubber' soles on nearly all shoes conduct.
#22
Back to the original post, why not a cold cathode? Cold cathode = 2 wires.... LEDs = 2 wires for each LED
#23
Quote by aschaetter
Back to the original post, why not a cold cathode? Cold cathode = 2 wires.... LEDs = 2 wires for each LED

Noise?
#24
Yes, VERY noisy! I'm messing with some EL wire with one of my amps, and having an awful time getting rid of the inverter noise! So far, I have the inverter installed separately in a cast aluminum box that's grounded, and can still hear it.

Edit: Since you want the LEDs near the tubes, and the heater power is right there, not much extra wire, if any would be required.