Update: We have upgraded our pa & IEM. We are now using a RCF digital mixer M20X, which is excellent( sound & functionality). A side effect is that; when we connect to our wireless IEM the latency and ground noise is much more noticeable. As we don't use any backline and we have a very high quality FoH, we want the best IEM, so we have decided to use studio quality amplifiers and have our in ear wired. I have been testing for a week and so far the results are very good, as a result the Co "DACS" is making a 1U rack for Fynnius Fogg. See page 1 for old rack pic, and new system below. The new rack contains a isolated/ stable power supply + the headphone amps + bass wireless unit with the mixer on top. We have a permanent set up installed in or rehearsal area, where we use headphones...For gigs we use high quality in-ear...hopefully:we will be setting this all up and fine tuning from 17th May...with our first open air gig 20th June. Hope this encourages others!