I seem to remember from the period where I was researching for my JCM800 purchase (which never happened) that you have to be very careful with 220X amplifiers. There were serious revisions made to the series, meaning that depending on the period of amplifier you buy you might have equalisation before preamp gain (which leads to a horribly muddy tone), which is just one of the many changes they made to the series. If I'm right, then there were a couple of years where they were producing 'the' 220Xes that you've heard so much about; go either side of those years and things start to look a little less peachy.
