Rbf,
In general, listen for any audible signs of distortion or breakup usually due to amp clipping. When an amp clips, distortion will start to become audible during louder musical peaks and upping the volume further results in more distortion than increased volume as expected. I have never been able to overdrive any OHMs I have owned and get them to breakup otherwise. I suppose it is possible with a larger amp on a smaller OHM like a MWT. I doubt a Peachtree Nove would overdrive any OHM Walsh, so clipping as I described above is the thing most likely to watch out for.
In general, listen for any audible signs of distortion or breakup usually due to amp clipping. When an amp clips, distortion will start to become audible during louder musical peaks and upping the volume further results in more distortion than increased volume as expected. I have never been able to overdrive any OHMs I have owned and get them to breakup otherwise. I suppose it is possible with a larger amp on a smaller OHM like a MWT. I doubt a Peachtree Nove would overdrive any OHM Walsh, so clipping as I described above is the thing most likely to watch out for.