but there are some aspects of this Frankenspeaker mashup to consider. First of all, there's the question of impedance matching between the amplifier output and the larger speaker. The probably higher weight of the larger speaker cone may also be a problem for the amplifier because chances are that the Yamaha amp is based on a small op-amp included with just enough output to handle the original smaller speaker. When you start driving the new setup, the op-amp will be running hotter than designed for. Excessive heat means bad news for the longevity of of any op-amps involved.
Any honest tech that works on speakers and amps will tell you that a speaker driven by a low wattage amp can be destroyed quicker than using a higher wattage amp. The low wattage amp will go into clipping or distortion more easily and could overheat the voice coil in the speaker. That's not to say you can't hook it up if you're not worried about the gear. It could be kind of spectacular to watch it in its death throes or at least educational. If you need a new amp and speaker combination, wait a little while for your stimulus check from our friends in DC and then do your due diligence before you put your money down.
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