Marble drive

[Jiuk]

My version:
R2, R3, R4, R6 ; 1/2W carbon composition resistor. It makes sound rough & muddy.
R5, R7 ; carbon film resistor
The other resistors are metal film resistor.

Trim 1: 4.0V
Trim 2: 5.0V
Trim 3: 8.0V

 

[Barry]

Nice build!

 

[chongmagic]

Another nice build, great job!