Vintage hi-fi gear can be very attractive, particularly compared to modern stuff. However, when this stuff starts getting into its third or fourth decade after production, things start to wear out. Chief among them—the little incandescent bulbs that light up the dials with such a beautiful glow. [Piffpaffpoltrie] was suffering just this problem on an old Technics amp, and decided to go for a more modern upgrade.
Replacing the original bulb with a like unit was undesirable—even if many last for decades, [Piffpaffpoltrie] didn’t want to have to tackle this job again in the future. Instead, an LED swap was the order of the day. A short strip of warm-white LEDs seemed to be the perfect solution, with three LEDs in series being just about right for the 11-volt supply used for the original bulbs. The only problem was that the stereo supplied the bulbs with AC, not DC. Thus, a quick bridge rectifier circuit was thrown in, along with some series resistors. This wrangled the voltage into a straighter line and delivered the right voltage level to drive the LEDs nicely and smoothly.
The result is a nicely-illuminated set of power meters on this vintage Technics amp. We’ve seen some neat LED swaps in the past, too, including this tricky motorcycle lamp upgrade. Meanwhile, if you’re slogging it out to bring your vintage gear more up to date, consider dropping us a note on the tipsline.
Did similar on my Christmas tree: was using a 12V 20W halogen bulb and the power supply was getting very hot, so replaced it with a 12V 10W LED cob. Saves on my bill and PSU not getting nearly as hot.