This amplifier is based on the Mitsubishi RA30H1317M amplifier module. A sample was kindly provided by Mitsubishi for this project a year ago and I finally got around to building it. After construction, the amplifier would oscillate providing about 20w output when connectced to the DSP-10. It also oscillated with the key line connected to the DSP-10 but without the RF input connected. I first placed a shield around the module more to provide adequate grounding with very low inductance. This did solve the problem with the RF input not connected but it still oscillated when the RF input was connected. A friend suggested I place a 3dB attenuator on the input to the amp. This solved the rest of the oscillation problem. It appears the RA series amp modules need to see 50 ohm resistive on it's input. When I get the chance, I will put a 1dB resistive pad on the board and see if that takes care of the oscillations.

Below (click on the photos) are some construction notes on the brick amp I built.