Hi there I thought I would try something new to me with my Neve Portico 5016 yesterday and record 2 bass tracks simultaneously. The 5016 is a 2 channel unit with 1xMic Pre and 1x DI/Line Level. My set up was: 1. My Fender Jazz Bass going into the DI then going into my RME Multiface 2 then into Sonar 7 PE. 2. The Fender Jazz Bass signal (unaltered) simlutaneously being routed from the THRU ouput of the 5016 to my modest Fender Rumble 15 watt combo. This then having an SM57 pointed at the speaker cone going into my MIC PRE side of the 5016, this also going into the RME Multiface 2 etc. When I tried to do the above, I seemed to get major noise issues with a constant buzz coming through the Fender Rumble combo which would get louder as I raised the volume. It also happened with a Marshall amp I have too. Therefore, may rule out the amps at this point. I drove myself mad trying to get rid of this buzz which at times sounded as though it had a clock ticking through it. GGrrrr. I am not an expert on gain staging. Therefore, if this is the issue I would be grateful for advice in solving the issue. I will describe a few things below: My Bass guitar volume knobs were turned all the way up as this is something that I was always told to do. Was this good advice as it ties in with what I have read regarding that good gainstaging requires that you get as much hot signal into the signal chain as early as possible? Even with my DI on the 5016 turned all the way down, the Fender Rumble buzzed. This was also the case with the MIC PRE turned all the way down also having the SM57 disconnected from the 5016. Therefore, I got the buzz from going into the 5016 (turned all the way down), then from the THRU>>>Fender Rumble. I am just totally stumpted as to why this has happened. I tried the Fender Rumble in another room to no avail. Even my mouse on the mousepad was making sounds in the buzzing. If any louder I would have been able to mimic the record scratching breakdancing stuff from the 1980s using my mouse...lol I tried switching to other guitar cables. Incidentally, I was using unbalanced mono cables from the Bass>>>5016 DI and from the 5016 THRU>>>Fender Rumble as the 5016 stated that the THRU takes an unnaffected signal to an external amplifier. The Ground Lift Switch on the 5016 marginally helped. However, this tended to affect the DI track. Therefore, everything was now buzzing. In fact, the only way I can get rid of the buzzing is to disconnect the THRU output and unswitch the Ground Switch and solely use the DI. I do not think the issue is the 5016 or Fender Rumbles proximity to other gear as I also tried thing quite spaced out. Is there sonething I am missing regarding the intended use of the 5016 or something? This is what the manual says: Any advice on sovling this would be gratefully appreciated. Regards Lid.