Purchased on ebay a few years back. all sliders, switches & pots flushed with DeoxIT D5 then treated with DeoxIT D100L. Filter Level pot has a bad spot between 7 and 9ish. all sliders & switches work fine and smooth. This unit had been modified by the previous owner. check out the back compared to a normal one. the marker writing on the inputs and outputs is from me so i could remember. Looks like it was set up to feed the older RCA inputs on tape machines has the high , low ,and direct output added the Xlr out is "disabled". the Xlr in "is" the input. Very useful for many things. I have had it for a while and selling to buy something new to play with.