The following is available by sending the receiver to Kiwa Electronics.
Audio and Switching Diode Upgrade
This is a two-part upgrade. The first part involves replacing all the audio coupling capacitors that limit the audio performance with types that will improve the audio clarity. The end result is better definition of consonants that improves intelligibility. The second part involves replacing the silicon switching diodes for the WB/NB filter selection with a Shottky type. We also replace the inductors within the the filter switch with ferrite shielded types. This improves the isolation between the selected filters.
Audio and Switching Diode Upgrade $70.00