Here is the most straightforward way of ascertaining whether a power amplifier will be stable (ie, won't oscillate) in actual use, with adequate protection against damage if it does oscillate. Low-current fuses are the cheapest form of protection.
If the amplifier is already equipped with speaker fuses in its outputs, replace these with 0.25A (250mA) fast-blow fuses. (If it hasn't its own fuses, buy a couple of standard in-line fuse holders, put one in series with the Hot output from each amp channel, and install the 0.25A fuses.)
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