Even better Vibro-King "Ticking Tremolo" fix
Here's an even simpler trem-ticking fix for the Vibro-King. Starting with a stock amp:
- Cut open the trem bug.
- Remove the neon lamp.
- Replace the neon lamp with a red LED. (See notes.)
- Tape up the modified trem bug.
Note 1: The LED is polar, so it'll only work one way. Before you tape up the trem bug, warm up the amp and see whether the LED blinks. If it doesn't, reverse its leads.
Note 2: You should pick an LED that's about the same size as the photocell(s) and frosted so it diffuses the light to cover the cell(s). I spec'd red because the red LEDs seemed to be brighter than the yellow and green LEDs that came in the same blister pack I bought from Radio Shack.
This fix works because the LED is a current-sensitive device and the trem circuit contains a 100K resistor to limit the current to an appropriate value for the LED. The ticking is gone because there's no sudden large voltage change across the LED (as there was across the neon lamp) to get coupled through the photocells into the sensitive audio circuitry.