When controlling amplifiers larger than 200 watts (8-ohms), you must use an external DPDT relay. The 372 SPL Computer’s internal relay cannot handle more than 8-amps of load current. The recommended maximum amplifier wattages are as follows: 300 watts at 70V, 200 watts at 8-ohms, and 100 watts at 4-ohms. The 24-volt version of the Potter & Brumfield PRD11DGO works well. Its DPDT contacts are rated at 30 amps.