Tracking down the source of amplifier hum.
38:28
Marantz 2500 Troubleshooting a Hum Problem
1:34:17
Quad 405-2 Amplifier Repair and Refurbish - Step by Step
32:47
74 Marshall 1959 Restoration. ELIMINATING MAINS HUM!!
53:21
NAD 3020 Series 20 Vintage Amplifier Repair
47:04
Audio Research Reference 600 Mono Block Amplifier Troubleshooting And Repair!
42:14
Akai 4000DS MK2 Reel to Reel has severe amplifier noise and very high flutter
27:17
Oscilloscope: DC & AC, Signal Tracing in Amp Circuit, RMS Output Measurement
46:56