Amplifier Troubleshooting

[boywonder]

One thing you could do is wire them across your speaker terminals without your speakers attached, let your amp warm up and measure the voltage across the terminals and see if it is still motor boating.

The resistors have far less inductance then actual loudspeakers (pretty much just resistive depending on the resistor-some are entirely non-inductive, which is what you want.)

The other thing you can try is to wire them in series with your speakers (effectively doubling the load the amp sees) and see if the motorboating reduces/stops by observing the cone motion.

If the motor boating persists with just the resistors attached, the amp has a low freq stability problem.

[boywonder]

Originally Posted by boywonder

The other thing you can try is to wire them in series with your speakers (effectively doubling the load the amp sees)

Correction: should be "effectively doubling the resistance the amp sees"....

[cogsncogs]

Since it's alternating between channels, a good place to check would be the power supply caps (clue: decoupling) especially if they are common to both channels.