Correct. The 1uf will filter the supply. 64 ohm means 32 ohm + 32 ohm. If you use voltage like 6V or higher, you can also use 300 ohm + 300 ohm like HD600 to achieve higher gain.

I know it is hard to believe but just give it a try and let me know if something goes wrong.

Thanks,

Adam

在 2018年10月15日，上午11:41，Rob via Groups.Io <roomberg@...> 写道：

I pu tthe images here just for discussion.
I cut out the Xed parts..... and got this: 
http://www.learnmorsecode.com/DC/rong1.jpg
Am I reading this correctly?
PLUS VOLTS  to the NE602 is after the speaker?
and
what is 64-600 ohms mean?