Tube Amps / Music Electronics
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|previous: Jim S. Having recently purchased a pair of... -- 10/3/2000 7:15 PM||View Thread|
|10/3/2000 8:06 PM|
|Gil Ayan||Re: D-Clone question - lamp on back panel?|
Jim, that feature was discontinued by Dumble in most recent models. However, old amps had the 50/100W switch and an LED (bezel mount) indicator. As you'd have it, the LED was on when the amp was in 50W mode -- don't ask about that particular wiring because no one will tell you. Sorry.
However, you can find an alternative way to wire the LED and have it be on in 100W mode if you so choose. Merely use a DPDT mini toggle switch for the 100/50W switch; one pole can disconnect two cathodes from ground, and the other pole energizes the LED.
By the way, the indicator on the front panel is also a bezel mount LED. Modern Dumbles use LEDs, onlder ones used different neaon lights. You can buy these things from Mouser electronics, and some even have the dropping resistor included in the assembly. The easier way to power the LEDs is to build a trivial power supply from the 6.3VAC filament supply. All you need is one diode in series with a dropping resistor and you have yourself some "cycling DC" that will happily light up the LED. The dropping resistor can be anywhere between 1K and 390 ohms.
|Jim S. Gil,|