Mitsubishi brick amp - lead length
Posted: Tue Mar 06, 2012 2:48 pm
I have an amplifier using the Misubishi RA18H1213G which I built some time ago using the Mini-Kits board. This amplifier gives excellent power out but has consistently been at the bottom end of the quoted gain range at 22dB. I have used all the usual construction precautions and can only see one possible cause of loss.
The Mini-Kits PCB is made from a fairly thin (FR4?) board which has to be mounted flat on the heatsink tight up against the module. There is about 1.5mm or 2mm hight difference between the module lead-in and lead-out out and the PCB so there is about 2mm of lead from the module to the 50 ohm strip line on the board. Could this cause loss at 23cm? If so I will have to make an aluminium spacer between the PCB and the heatsink to raise it.
Dick G4BBH
The Mini-Kits PCB is made from a fairly thin (FR4?) board which has to be mounted flat on the heatsink tight up against the module. There is about 1.5mm or 2mm hight difference between the module lead-in and lead-out out and the PCB so there is about 2mm of lead from the module to the 50 ohm strip line on the board. Could this cause loss at 23cm? If so I will have to make an aluminium spacer between the PCB and the heatsink to raise it.
Dick G4BBH