[Phil Allison[_4_]]

Scott Dorsey wrote:

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Remember the *only" connector is a HP jack.

IME, such units do not have enough metal shielding to exclude
buzz and hum from fluoro and dimmed domestic lighting.


I have a little box that has 600:600 transformers in it and a shunt load
on the transformer secondary. The idea being that with a lower impedance
load, the keyboard noise is less severe. I have really only had to use it
with $10 Casio keyboards, gameboys, and the like, but it helps a bit for
the really cheap stuff.

** Grounding the common rail inside such contraptions often makes injected electrical noise from the environment worse.

What do you mean by "grounding?"


** I was referring to poorly shielded, $10 contraptions.


The grounds on the input are not bonded
to the grounds of the output. (They can be with a switch if necessary).
The idea is to float the two grounds.


** Yep.

The other dodge that works is to place the contraption on a sheet of metal much bigger than the device and ground that with a clip lead.

Mind you, no fluoro tubes switched on in the same room.


...... Phil