David99 -- a bit late in the day, before you purchase anything, try programme material with ridiculous low frequency content (Bjork; anyone with synthi /emi induced "bass"). Look for cone movement that is NOT coincidental with the music being played... try to note the speed with which the cone STOPS moving (not starts) vs. the sound you hear. Try to check for intermodulation distortion -- example, trying to reproduce voice + unnatural bass.
If you can't detect anomalies, stay with your amp. If yes, you probably have to buy vintage and save up for extensive repair.
If you can't detect anomalies, stay with your amp. If yes, you probably have to buy vintage and save up for extensive repair.