Hope this thread is in the right forum, and that it isn't a duplicate. That said.... Tonight I just racked up my new EA iamp800 into a 3 space SKB rack. I have also purchased what is by all accounts a high quality (slightly used) 31 band graphic EQ to use with it for DB - an Ashly MQX 1310, which I placed in the space above the iamp. I'm using a Raven Labs PMB-1 as a mic/pickup blender on my DB. My plan was to go into the blender, have the graphic wired into the effects loop of the blender, then go out into the iamp. When I turned everything on, there was a hum/buzz coming out of the speaker, so I checked the signal chain, pulling out one thing at a time, until I discovered it was the EQ (when I unplugged the EQ from the effects loop, the hum went away). What's weird is that when the EQ was wired into the effects loop, the hum was there whether the EQ was "in" or bypassed, and it was still there even when the EQ was turned completely off! Pardon the expression, but ***??? Aside from the hum, the unit doesn't seem to be noisy at all, and I've heard nothing but great things about this brand of EQ. I'm stumped. I'm also the first to admit that I've never used an effects loop on a bass amp before, so I might be doing something really obviously wrong. If anyone could check my signal chain and make any suggestions that might help, I'd be very grateful. THE CHAIN: Stereo out on DB - - -Stereo in on Blender - - -Effects "send" on blender - - - Balanced "in" on EQ - - -balanced "out" on EQ - - -Effects "return" on Blender - - - Line Out on Blender - - - Input of iamp. The VARIABLES: 1)The Raven Labs blender has an "Effects Blend" pot on it. The hum is worse when the knob is turned full left or full right, and better (but still present) when it is at dead center; 2) The ins and outs on the EQ are balanced. The unit has both XLR and 1/4" ins and outs. I was using the 1/4" connections. I tried both balanced (TRS) and unbalanced cables. (I should mention that the only balanced cables I had were part of an 8 cable recording snake, but they are dead quiet for my recording gear). 3) Thinking the problem might be the effects loop on the RL blender, I tried using the effects loop on the iamp, but got the same results, even when the Ashly EQ was turned off. I'm stumped. If anybody can help clear this up, I'll owe you big time. Thanks.