• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Voice of Music 1428

Hi, I'm restoring a Voice of Music 1428 Tube Amp and found the incandescent power indicator is burnt out. The Sams schematic doesn't specify a part. Per the attached schematic it runs to the center tap of the 6 Volt filament transformer witha 10 ohm series resistor. Can anyone suggest a replacement bulb or LED combo for this bulb? Since this indicates power in a high voltage amp I want greatest reliability which may be an LED.


thanks
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thanks in advance
 
Ok, what you have is known as a grain-of-wheat bulb. These are T-¾ size lamps. Many of them are 5v at 60ma. But they also come in 12v and perhaps lower then 5v. Since yours is connected through a resistor to ½ the 6.3v filament voltage, they're probably low voltage. Perhaps get some 5v lamps and operate it from the 6.3v through a suitable resistor. Or just the 3.15 half as shown. Lamps operated at 10% lower then rated voltage last a very long time.
 
Ok, what you have is known as a grain-of-wheat bulb. These are T-¾ size lamps. Many of them are 5v at 60ma. But they also come in 12v and perhaps lower then 5v. Since yours is connected through a resistor to ½ the 6.3v filament voltage, they're probably low voltage. Perhaps get some 5v lamps and operate it from the 6.3v through a suitable resistor. Or just the 3.15 half as shown. Lamps operated at 10% lower then rated voltage last a very long time.
Thank you. I should be able to find a 4.5 Volt grain wheat bulb and run it off the 3 Volts as suggested for longevity
 
Ok, what you have is known as a grain-of-wheat bulb. These are T-¾ size lamps. Many of them are 5v at 60ma. But they also come in 12v and perhaps lower then 5v. Since yours is connected through a resistor to ½ the 6.3v filament voltage, they're probably low voltage. Perhaps get some 5v lamps and operate it from the 6.3v through a suitable resistor. Or just the 3.15 half as shown. Lamps operated at 10% lower then rated voltage last a very long time.
Do you see any issue using a 5 Volt one off the 3.1 Volt tap? Bulb in question is: 5 Volt, 115 mA Grain of Wheat Bulb