I'm sure instruments4music are fine as a supplier but I have emailed them already regarding the second example of these amplifiers they have sent me (the first one was returned within the returns period) and, because of the strange and very loud interference type background noise they make - cross between a sewing machine and a hammer drill, through compatible speakers or through headphones with an instrument plugged in or not and with no interference sources nearby - I'm afraid I can't sing the praises of these units. If they are all like the two I have tried I can't see that they would have any use at all. I wanted this amp as a spare for gigs and because it has an input for media and output for headphones for silent practice at home but it has not, unfortunately, fulfilled either of these expectations. In my earlier email I asked if others have found the same problem and if there is a fix. Surely I can't have been that unlucky. I use good quality cables and have never encountered this sort of hiss and crackle/rumble noise level with other amps I've used. Again, no reflection on the supplier just the unit I purchased was not up to even the most basic expectations. Regards, Chris Dolman