Have you bought bulbs recently...

[joeinbcs]

You are not looking at the right vendors if they are not listing the 'color' of the 'white' lamps. Same deal when you are buying lighting for your house or whatever.

For a good vendor/product it should give the color temperature in Kelvin like say 2700k.   They will often give you a name like cool or warm but that is much more subjective.   2700k is about as close as it gets to a standard classic light bulb.  5000k is your classic institutional florescent color.   There are 4000's that are a little less harsh.   3000's just slightly whiter.  2100k is the 'antique' usually open filament look and that is really getting into the yellow candle light range.

I just took a quick look at SuperBrightLED's site that was mentioned before and they do give the color temps of the 'white' lights.  Many types look to be available in something in the 3000 range and in the 5000 range just like going to home depot for your home. 

Thanks a lot.
I ordered my bulbs from Super Bright.
They make it easy with model specific bulbs, and in the right color.

[Roger Zimmermann]

But, can LED's be used in Dash Boards and the rheostat still work as intended?

Yes, Bruce. The ones I bought from the company cited by TJ Hopland are dimmable. They are more expensive than regular ones: I paid $ 4.95 each in October 2019; I installed them into the dash from the '72 CdV.

[TJ Hopland]

I think I mentioned earlier in this thread that from a technical standpoint dimming an LED in a DC circuit with a rheostat is about as easy as it gets.  If you want to get real technical and talk about the color temp as it dims and how much you turn the dial vs apparent brightness compared to a standard bulb then its more complex but it seems that most people are satisfied with the performance of more recent offerings.  Today's LED's are not the same as they were 15 years ago when they first appeared on the market. 

And a little more non car specific LED ramblings for anyone who is interested......

In a home situation off of a much higher and AC voltage is where dimming gets complicated to do cheap and even more difficult if you want the same range and color as a standard bulb. Oversimplification time.  Most led 'bulbs' have several LED units on them and each one runs at a couple volts so even in a 12v circuit you have to do something to reduce the power each one gets but on the scale of something like a dash light it can be as simple as a resistor. 

You start talking something like a headlamp or 100w equivalent home lamp it gets a little less practical to just burn up that extra power creating heat in a resistor.  You them add AC power to the mix maybe even 240v in places other than North America and it can be done cheap till you want to dim it.  The cheap and compact way to build a dimmer kinda chops up the AC power wave and guess how the cheap and compact way to design a LED lamp works? Chop up the power wave.  So the LED bulb now sees a chopped up mess and its trying to further chop up that mess so things get a little inconsistent and unpredictable.

You can make them smart and actually have a brain of sorts on board to understand whats coming in and how to properly modify that but the brains need steady power to run themselves so you end up needing a constant power signal plus the control signal which wasn't how things designed in the incandescent days were wired so its no good for retrofits and adds a lot of cost to a new build.

Theatrical and high end architectural lighting is the 'smart' type where its fed a constant power source and then a control signal.  The control signal can be a simple variable DC voltage or a fancy networked digital signal.   Each fixture then has its own internal proper power supplies to make the proper voltages and they will often have dozens of actual LED elements and optics to get the desired performance. 

They will often have several colors and the ability to change and alter their color not only for literally changing the color from say green to blue but they can use all those colors to create the different shades of white and mimic an old school bulb that would change colors slightly as it dimmed.  The brains do all this by having individual control of each of the LED elements in the fixture.

Its super cool stuff and could you do that in the dash of a car or in your garage light?  Sure but its super expensive.  In stage lighting one of the classic lighting fixtures was called a PAR64.  It was basically a paint can with a car headlamp in it.  If you can still find the old school ones in the modern 'import' quality they cost about $60 today.  The total crap quality LED version is about $300.  That gives you an idea how much more complex they are and that is crap, the good brand pro stuff is easily $1000's per fixture. 

           

[Highwayman68]

I am interested in hearing about which bulbs were purchased and turned out to work well for the dash. I have a 68 I would like to update.

[Roger Zimmermann]

At that time, I bought from Superbrightleds #194-NWHP5 natural white and #194-WWHP5 warm white.
I cannot remember what I installed; anyway those led bulbs are 10 times better than the original ones
which were not bright enough.

[gkhashem]

Wake up everyone. This is not just bulbs. Many items are no longer being made from what I can conclude.

How about looking for an air filter or fuel filter for a 1959-1960 Cadillac?

Wix items are no longer in stock. One good thing about being a parts hoarder is that I have enough for my lifetime but do you?

Go looking for the items and see for yourself. Then panic about what will not be available next. Once the pipeline is dry I think its over. Is this by chance or a plan to make our classic cars large paperweights. Is gasoline next?

[Bryan J Moran]

I talked to an LED Bulb vendor at a swap meet, who advised that they can't be dimmed. They are either on or off.

The dash lights on the 57 Brougham are a monumental pain to change, and many are burned . I'd like to do the job once during my tenure and be done with it. But don't like the idea of the dash being so bright as to be distracting.

GB

I wonder if a resistor can be placed in series to provide less amperage so it's not as bright. 

[Eric DeVirgilis CLC# 8621]

The subject of LEDs frequently crops up in vintage hi fi equipment forums and it's a fact that certain LEDs do not respond to voltage changes in order to make them dimmable. I know this firsthand when I did an LED swap in a tuner-preamplifier with a dimming switch. Maybe some do but not all.

[J. Gomez]

All LEDs bulbs have a regular driver thus making them non-dimmable, dimmable LEDs have a special built-in driver that allow it to be dim by fast switching the current (turning on-off) to the LED, so slowing the switching rate will make the LED to dim while a faster switching will make it brighter.

If you have the old rheostat style headlight switch using dimmable LEDs it will dim them slightly (about +/-80% from full bright) if you have them all working on the circuit. The drivers provides a slight load for the rheostat to drop the voltage, BUT as with the old incandescent lights if any bulb goes out the load diminished so the rest will dim less (but the rheostat will not burn-out as it traditionally happens with the older incandescent ones).

[TJ Hopland]

All LEDs bulbs have a regular driver thus making them non-dimmable, dimmable LEDs have a special built-in driver that allow it to be dim by fast switching the current (turning on-off) to the LED, so slowing the switching rate will make the LED to dim while a faster switching will make it brighter

For line/mains voltage lamps that is certainly the case.  Have you seen low voltage (12v)lamps that have more than a resistor in them?  I have not.  I'm not saying they don't exist but especially in the context of a 12v dash light sort of application there really would not seem to be any reason to do anything more complex. 


I could see major issues in the dimming and appearance if you are mixing bulbs in the same circuit.  The dimming 'curve' of an LED vs a regular bulb will for sure be quite different.  The LED will typically not really appear any less bright through much of the dimming range then with a fairly sort amount of travel of the dimmer will dim though its range which in most cases won't get that dim before it just goes out.  That dim to go out point can even vary bulb to bulb so if you want to operate near that part of their range it may be tricky to find a spot where they are all still on. 

The other trick the dimming LED industry plays on us is when they say 'dims to 20%' that is from an electrical consumption point of view.  If its a 10 watt lamp they are saying you can dim it to 2 watts and a 1.9 watts it will go out.  That may be true but its pretty useless information to the average human that just cares about the apparent brightness.  Its pretty likely that most people would perceive that 20% as maybe only half as bright as full bright which won't usually be dim enough for many applications. 

Thats why things get expensive and complex.  To make a lamp that really performs like an incandescent its got to be like I mentioned above where its got several different color and brightness led elements in them and the internal brains mix and sequence them to get the desired effect.  Totally doable but way more complex than it was with a incandescent lamp.       

[J. Gomez]

TJ,

For line/mains voltage lamps that is certainly the case.  Have you seen low voltage (12v)lamps that have more than a resistor in them?  I have not.  I'm not saying they don't exist but especially in the context of a 12v dash light sort of application there really would not seem to be any reason to do anything more complex. 

In a nut shell a regular LED is either "on" once it reaches its operating voltage or "off" once it drops below its threshold.

The very early version of LED bulbs (12V ones) were just a standard LEDs with resistors to drop down their operating voltages, since them things have change radically in their production. You now have them with all integrated LED and driver in a single chip.

I could see major issues in the dimming and appearance if you are mixing bulbs in the same circuit.  The dimming 'curve' of an LED vs a regular bulb will for sure be quite different.  The LED will typically not really appear any less bright through much of the dimming range then with a fairly sort amount of travel of the dimmer will dim though its range which in most cases won't get that dim before it just goes out.  That dim to go out point can even vary bulb to bulb so if you want to operate near that part of their range it may be tricky to find a spot where they are all still on. 

You can still dim the ones that are not "label dimmable" by reducing the voltage, so at 12V it will be full bright and dropping them to around 5V or so it will be very dim. Reducing the voltage down this low will be impractical and will required a more complex setup to accomplish the dimming.

With the dimmable LEDs the driver will increase or decrease the rate of switching depending on the small voltage drop from the rheostat to dim the lights, so this switching rate is a visual effect on how long the LED is turn on and/or off mimicking to dim them.

Not so with the old incandescent lights of just having a simple large rheostat to dissipate the current to drop the voltage to the filaments to dim the lights. The caveat with this is you have to match the overall bulbs filament resistance to the rheostat if you do not you may turn it into a cigarette lighter.

So I agree that not all LEDs are made the same even from the same company and/or batch and the behavior of the dim may not be the same with the older rheostat setup using dimmable LEDs versus the old incandescent bulbs.
 
But if one does not care that the LEDs will not dimmed down to the same ratio as the old incandescent ones do, then I would guess that is fine. On a second point this will also save the rheostat life as well since the load will be far less.

HTH

[bcroe]

All the above is important, but old eyes here are just
as happy running near full bright all the time.  Certainly
I have tired of trying to keep good incandescents in the
instruments of my very high mileage cars, the dimmer is
more of a way to compensate for older bulbs.  Just getting
the bulbs out can be quite a chore (that one would rather
not repeat), and too often the heat of the originals has
damaged the connections to the mount over time.  While
I have found a fix for that, it still means pulling the
entire unit. 

So LEDs look like a permanent, one time fix.  My new
problem is getting uniform light on the instrument
scale.  I have resorted to mounting (soldering) the
LEDs in the best spots I can find, but do not think
the problem is entirely solved.  Bruce Roe

[V63]

It does seem the LED is a more usable light, just a better illumination.

[Highwayman68]

Those who are using the HP style, are you using the HP3 or the HP5. I want to know if the HP3 is bright enough or if the HP5 is too bright.