you should increase the volumne level to 0db. When I do this, I get a severely distorted sound from the amp (kind of like it's being overloaded). My amp is certainly not cheap (and neither are the speakers) so what is going on here?

It could be the empeg is over-driving the input you are using on your amp. It outputs around 3.7 V at line out. What would be worth doing is looking at your amp's specs to see if the input you are using is suited to a drive voltage at this level. If there is another, use that at 0 dB. If not, retain the same one, but by dropping the empeg output by steps of 3 dB you correspondingly reduce it's output level by 50%. If your amp will tolerate (say) 2V line in, then set the empeg to -3 dB and this will be adequate.

As for the hissing noise, it could stem from overdriving your amp's inputs, which sound to be quite sensitive. Experiment a little with levels. Otherwise, I would say - don't light any matches!

One of the few remaining Mk1 owners... #00015