[Elecraft] K3 Noise Blanker ahead or behind roofing filter?

[Dale Boresz]

Hello Brett,

Sorry, this is a little off topic, but ...

Shunting loudspeaker terminals on an amplifier (or at the loudspeakers 
themselves) may cause instabilities with some amplifiers due to phase 
shift, causing them to break into oscillation well out of hearing range, 
resulting in possible failure of the output transistors (at the very 
least), and some embarrassment and expense to the applicator  :-)

It's usually more effective (and will not cause any instabilities to the 
amplifier) to place ferrite beads over the individual wires or over the 
pair of wires (whichever works best) as near to the loudspeaker 
terminals on the amplifier/receiver as possible.

Sometimes, due to the size of the connector terminals at the ends of the 
wires, it is not possible or practical to fit a ferrite bead over the 
wire. In those instances, you can obtain some split cores from Radio 
Shack, Mouser, Digi-Key, etc. that will allow you to wrap several turns 
of wire around half of the ferrite core that is temporarily opened, 
after which you can close it again. Keep adding more of these devices 
until you no longer have a problem.

73, Dale
WA8SRA


Brett gazdzinski wrote:
> .... Some caps across the speaker outputs cured it
> totally!
>
> Brett
> N2DTS
>
>