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Thread: Standard bulbs and LED replacements / alternatives

  1. #1
    Join Date: Sep 2009

    Location: Derbyshire

    Posts: 9,228
    I'm Josie.

    Default Standard bulbs and LED replacements / alternatives

    Hi all.

    I have a bulb out on my tape machine which are easy to replace.

    It's a telephone slide bulb and is rated at 24v 50mA. Pic below.

    I'm looking for a suitable LED replacement if possible, if not the olde incandescent are fine but with LED I can hopefully get coloured ones which might be nice

    Any help would be great as RS have some LED ones but are I can't find any which are rated at 50mA.

    Thanks
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  2. #2
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 6,089
    I'm Alan.

    Default

    Hi Josie. 50mA is a lot of current for an LED, particularly as newer LEDs become even more efficient.
    50mA for a filament bulb is to be expected as their efficiency is abysmal in comparison.

    If there are the slide type LED that is specified for 24V then go with that, the current won't matter.

  3. #3
    Join Date: Aug 2008

    Location: Suffolk, UK

    Posts: 1,473
    I'm Paul.

    Default

    Another option is to use a bog standard 5mm LED and a 1K Ohm, 1 Watt resistor. Connect the resistor in series with the LED. You might be able to mount the LED and resistor inside the old bulb so that it is a plug in replacement.

    1K Ohm is not the exact figure, but it should be close enough. The resistor will dissipate approx. 0.6 watts and will get a little hot, so best go with a 1 watt.
    ~Paul~

  4. #4
    Join Date: Sep 2009

    Location: Derbyshire

    Posts: 9,228
    I'm Josie.

    Default

    Ah... thanks guys.

    Very helpful indeed
    Ultrafide U500DC power amplifier - Croft Vitale )highly modified) - TRIO L-07D Turntable - Denon DL103C1 - Funk Firm Houdini - Lentek MC head amp - 15" Tannoy Monitor Gold Loudspeakers in Lockwood Major cabinets (From Trident Studios) - Tannoyista SPEC 3 Custom Crossovers - VanDamme Black Speaker Cable


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  5. #5
    Join Date: Feb 2008

    Location: Middlesex, UK

    Posts: 4,481
    I'm Alex.

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    At work, we used quite a lot of these bulbs, got them from RS Components. Might be useful if you decide against LED.
    Spendorman

  6. #6
    Join Date: Aug 2008

    Location: Suffolk, UK

    Posts: 1,473
    I'm Paul.

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    I just based it on the forward voltage and forward current of an LED datasheet that I found on Rapid Electronics. The actual figure was 750 ohm, but I rounded up. Would be much brighter than a filament lamp to be fair.
    ~Paul~

  7. #7
    Join Date: Aug 2008

    Location: Suffolk, UK

    Posts: 1,473
    I'm Paul.

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    Why is it with LED torches that they don’t seem to produce much illumination but if you accidentally look at them straight on the glare seems almost blinding!
    ~Paul~

  8. #8
    Join Date: Apr 2012

    Location: N E Kent

    Posts: 51,624
    I'm Geoff.

    Default

    Quote Originally Posted by Primalsea View Post
    Why is it with LED torches that they don’t seem to produce much illumination but if you accidentally look at them straight on the glare seems almost blinding!
    Are you kidding? I have two compact LED torches that can light up the whole length of an industrial estate at night. They are wickedly powerful and you would certainly regret looking at one face on.

  9. #9
    Join Date: Aug 2008

    Location: Suffolk, UK

    Posts: 1,473
    I'm Paul.

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    OK, not sure what you’re doing in Industrial estates at night but what torches do you have?

    Although the batteries in mine seem to last a long time the light they emit is feeble and barely light up the end of the garden.
    ~Paul~

  10. #10
    Join Date: Dec 2014

    Location: UK, inactive

    Posts: 1,570
    I'm inactive.

    Default

    This may be of interest - from a discussion on the DADA forum:

    "The 303 is another story. The bulb here is a neon-lamp and hard to find. We usually replace it with a red square LED with a 12K serial resistor, connected to the 80V across the power-supply capacitor.
    A 230V Neon-lamp can also cause noise in the input circuits...
    See the 303 Upgrade / Revision manual for more information.

    Stefaan"

    http://www.dadaelectronics.eu/ForumR...&TopicID=47318

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