|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
|
Thread Tools |
18th Dec 2018, 1:25 pm | #1 |
Hexode
Join Date: Dec 2006
Location: Norwich, Norfolk, UK.
Posts: 440
|
Replacing dial lamps with LEDs
Hi All
Ive seen before that some people have changed the filament dial bulbs on a Bush DAC90A to LEDs. How easy is this to do, and how would i work out the value of resistor to use to limit the current and keep the current to the rest of the valve chain correct. Cheers Mike |
18th Dec 2018, 2:58 pm | #2 |
Dekatron
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
|
Re: Replacing dial lamps with LEDs
Hello, it is possible but have you considered the colour temperature? When I’ve done this (with another radio ) I was disappointed with the intensely white colour temperature.
Many people including me have good stocks of old dial light bulbs so ideally , ask for a replacement first
__________________
Al |
18th Dec 2018, 3:08 pm | #3 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,788
|
Re: Replacing dial lamps with LEDs
You certainly shouldn't use anything colder than warm white or it will look completely wrong - this applies to any incandescent replacement, not just in a DAC90A. Yellow LEDs often look best but you need to experiment. A lot depends on the tuning scale design.
|
18th Dec 2018, 4:37 pm | #4 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
|
Re: Replacing dial lamps with LEDs
I have had several LEDs from Bright Components (they have an eBay presence) - no connection other than a satisfied customer! - the warm white types are really good and I have used them as dial lights in, would you believe, a Vidor CN420a battery valve radio.
If I was LEDising a DAC90a (which I'm not), I'd be inclined to connect them in series with the HT rail, maybe in series with the 10kΩ smoothing resistor. It would have the slight disadvantage that you'd get no light at all till the radio warmed up, but it is probably simpler than fitting a diode bridge and mucking about with shunt resistors around the current bit of circuitry where the incandescent lamps are. You could use 3 or 4 in series, mounted on a little sub-panel of matrix board, and spread the illumination more evenly. |
18th Dec 2018, 5:12 pm | #5 |
Hexode
Join Date: Dec 2006
Location: Norwich, Norfolk, UK.
Posts: 440
|
Re: Replacing dial lamps with LEDs
Hi Guys
Thanks for the reply's, probably far easier to just get some filament lamps, im all for an easy life. Cheers Mike |
19th Dec 2018, 9:35 am | #6 |
Dekatron
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,145
|
Re: Replacing dial lamps with LEDs
Agreed! J.
|
23rd Dec 2018, 12:38 am | #7 |
Pentode
Join Date: Mar 2008
Location: London, UK.
Posts: 121
|
Re: Replacing dial lamps with LEDs
|
23rd Dec 2018, 1:56 pm | #8 |
Heptode
Join Date: Dec 2014
Location: Limerick, Ireland.
Posts: 901
|
Re: Replacing dial lamps with LEDs
It's easy to get the right current rating of lamp. An LED is a modernisation, like FET instead of RF Pentode.
The current rating is more important than voltage. Apart from the fact it's a modernisation and not restoration of a typically 60 years+ old radio the appearance is just wrong. Both at power on and running. |