Recently, I was involved in mixing a show where a keyboardist wanted to mix his vocal mic and keyboard through a keyboard amp and send that feed to the FOH mix console. The keyboard amp was an Alto Kick 12 that featured 4 input channels and balanced stereo outputs. The vocal mic was plugged into input 1 via the XLR jack and the keyboard was plugged into input 2 via the 1/4" jack. It took a few minutes to set the balance of inputs on the keyboard amp and then set the output to the FOH console.
During sound check the output level coming from the keyboard amp was too hot for the input on the mixer even with the channel gain set a minimum. Upon inspection of the keyboard amp I saw that the main output level was set to maximum and needed to be dialed back.
Next I needed to get a proper balance between the vocal mic (a headworn type) and the keyboard itself. At first the sound was not good because, the keyboard amp had EFX turned on along with the EFX at the FOH console. So, I turned off all the EFX on the keyboard amp and used only the FOH mix EFX instead.
After some tweaking I got a reasonable blend of signal coming to the FOH mix. The biggest issue was keeping a good vocal / keys balance throughout the set. If only the performer would have let me take his mic feed direct to the FOH console and not through the keyboard amp, I would have had better control.
Then afterward, I got thinking about an alternate setup that I should have consider trying if I had more time between sets. If I had an XLR Y-cable, I could have taken the vocal mic feed, split it into two feeds, and sent one feed to the keyboard amp and one feed to the FOH mix. I wondered if that would have lessened the amount of signal sent to the FOH mix.
Then I wondered about using a mic splitter to split the channel properly to avoid any ground loops issues. Of course, Radial Engineering has just the solution that would work for that setup. It is the Radial JS-2 Mic Splitter. See the application drawing below:
Just like the diagram shows, the mic signal goes into the box and two outputs come out and go to the two mixers. It shows two FOH mixers but, it would work with the mixer keyboard amp too. With this setup the keyboardist could adjust his keyboard levels to way he likes and I would have independent feeds for the vocal mic and keyboard allowing me to achieve a better balanced mix at FOH.