Re: Technics A1000 power amp - the lights have gone out !!!


"Keith G" <keith_g@xxxxxxxxxxxxx> wrote in message
news:431aca96$0$12890$cc9e4d1f@xxxxxxxxxxxxxxxxxxxxxx
>
> "Trevor Wilson" <trevor@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote
>
>
>>> Trevor's suggestion to get LEDs fitted is an interesting one but if the
>>> light level is to bright I would have thought they would look hideous.
>>> (TBH, if I couldn't fix them myself I wouldn't bother to get it done -
>>> they don't do much other than look pretty!! ;-)
>>
>> **LEDs are neat, because:
>>
>> * They are available in some nice colours. Blue LEDs, particularly, offer
>> spectacular efficiency gains over incandescent.
>> * They are easily controllable, either by a simple constant current
>> source, or a resistor.
>> * There are at least three different shades of 'white' available to suit
>> most applications.
>
>
> Last time I looked there were about 30 pages dedicated to LEDs in the
> Maplins catalogue....

**Sounds about right. Just to re-iterate and to expand on some
misconceptions:

* Blue LEDs are far and away the best types to use for various reasons. They
offer about 5% of the power consumption of an incandescent lamp of about the
same light output. The reason is obvious, of course - Incandescent lamps
have pitiful output at higher frequencies (IE the blue end of the spectrum.
Lifespan of blue LEDs is pretty much infinite.

* White LEDs are not much more efficient than a decent halogen lamp. This is
in direct contradiction of many who promote LEDs as the lighting system of
the future. They do have a long lifespan, however. Figure on as much as
50,000 hours (for 50% light output). They are significantly more efficient
than the longlife lamps typically used in audio equipment, however.

* White LEDs are fundamentally different to all other LEDs. They use a blue
LED chip, with a fluorescent coating. The blue LEDs 'energises' the coating
(which is usually yellow) and the resulting output approximates white light.
Different coatings allow manufacturers to provide different types of colour
balance. VERY similar to the operating principles and colour temperatures of
fluorescent lamps. Without the efficiency of fluoros, of course. Fluoros are
still MUCH more efficient than LEDs, of course.

* Most LEDs have a very narrow angle of output. My favourites are Lumileds,
which exhibit a 120o spread of light. Perfect for backlighting those old
1970s Marantz receivers (blue dials, you see).


--
Trevor Wilson
www.rageaudio.com.au


.

Relevant Pages

  • Re: Why are white LEDs so expensive?
    ... >Also I was under the impression that white leds are actually blue leds ... The working layers of blue LEDs are gallium ... Apparently the trouble with putting gallium nitride on gallium phosphide ...
    (sci.electronics.basics)
  • Re: Long life lights
    ... red, green, and blue LEDs create the effect of white light? ... Heck, equal numbers of R, G and B LEDs often results in bluish light. ... or so and have that modulate the brightness of a 1900 Kelvin source, ...
    (sci.electronics.design)
  • Re: Long life lights
    ... Colored LEDs, on the other hand, appear to me to have most operated for 100,000 hours or more to be keeping on trucking rather well after working for so long. ... It appears to me that better heatsinkable white LEDs take 50,000 hours to fade by 30% at "characterizing current" when heatsunk to what I call a "moderately conservative extent". ... Don Klipstein ... red, green, and blue LEDs create the effect of white light? ...
    (sci.electronics.design)
  • Re: Color Kinetics and the RGB patent
    ... There is nothing novel or unobvious to those in or out of the field about using a combination of RGB LEDs to create shades of color, as I am not a lighting expert and the idea occured to me many times before I discovered that it is patented. ... Patent systems in other parts of the world work properly. ... of red, green, and blue LEDs is rotten, and so I am planning to construct lights for my own use based on a full spectrum of LED colors. ...
    (sci.engr.lighting)
  • Re: Your government at work, Fluorescent Light Bulbs
    ... LEDs come in different color. ... green and blue LEDs are mixed ... fluorescent bulbs and NO MERCURY, ... bulbs and CFLs which have only one color. ...
    (alt.autos.toyota)
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