Ebtech LLS-8 Line Level Shifter 8-Channel Single Space Rack

It does a good job for my M50 to connect to M-Audio Fast Track Ultra 8R. FTU 8R is a "commercial grade" product so it doesn't work with "consumer products" that has -10db output. you need to bring up the volume to +4db. it did good job for the keyboard but not for the guitar effect processor Boss GT-10. it had some static I don't know may be I did something wrong, but later i found out Gt 10 has an option to turn volume up to +4db, so i didn't need it for the guitar effects processor. if you have multiple keyboards or midi players that you want to connect to a commercial grade equipment, it does function well. it doesn't need power. I should say there is no manual with it just one sheet that explains the uses of the product. It alsobrings the volume down from +4 to -10. and it has a built in hum eliminator.

I was skeptical if this product could take care of an unbalanced cable noise problem I was having in addition to adjusting line levels...Guess what.. it all worked as advertised.Significant drop in noise and hum along with line level balancing using TS Unbalanced cables...good stuff...

This product is excellent. It does what it is designed to do. I recommend it highly.