Vibrator - 4 Pin, for automobile radio

There is some hash noise, but adding a choke, and modifying the buffer cap circuit a little bit can help eliminate that noise. Option B is try to rebuild a mechanical vibrator. It's not impossible, but it can be a real challenge, especially if the contacts are burnt. This vibrator is basically just a very basic solid state DC to DC conversion chopper circuit. The new mechanical vibrators could be almost as square wave noisy as these solid state replacements, sometimes even worse, complete with switch bouncing, overshoot, creating even worse noise. When I ran other 6 volt AM radios, in other old vehicles I owned, running the radio without the engine running was somewhere between inadvisable and incredibly stupid. Starting my 1947 GMC with an Airline Wards add on radio on would fry the ignition points. When I finally found the stock General Motors radio, same deal, start the truck with the radio on, and burn the points. These 6 volt radios draw 18-24 amps. You may as well leave the headlights on too, and schedule AAA to come and give you a jump start in two hours. I'd say a half hour, but Arizona's AAA service is really slow, and horrible. The way my oil pan was bolted to a giant flange on the engine block, I eventually just added a 12 volt alternator to the truck, mounted on angle iron. It just bolted on, so totally reversible! Just like modifying that silver face Fender amp, if you don't like it, change it again. Slopifying the buffer cap by using two caps totem poled with balancing resistors can smooth out some of that noise. SOME LATER VAC TUBE CAR RADIOS ACTUALLY USED TRANSISTOR CHOPPERS INSTEAD OF MECHANICAL VIBRATORS! MAYBE PAY A VISIT TO YOUR LOCAL LIBRARY AND LOOK UP SOME HOWARD SAM'S SCHEMATICS!