Here's a passive switch that I built to allow me to connect my DAC to up to 5 amps or vice versa (although I highly doubt that that situation will happen). It's single ended so it has a common ground and a 2 pole 5 position rotary switch. I used Nuetrik Rean RCA receptacles, a NOS Alco non-shorting gold plated terminal switch and multicore stranded silver plated OFC wire with teflon jacketing. Part of my job is running a prototype machine shop so I modeled up the housing and machined it out of 6061 aluminum.
I spent some time swapping it in and out of line in my system to see what it did sonically. For me, I thought that there was a barely perceivable loss of fine detail with it in line but I was sure so I had my daughter come and do some listening for me. She concluded that that is the case. It's very subtle but there is a little degradation there. I'm not sure how much is from the circuit and how much is from the extra connections in the line. Also, in order to ad it into my system, I had to use one set of interconnects that are lower quality than the rest so that may play a small part as well. All that being said, the sonic differences are small enough that, for me the functionality of the switch is worth it so I will leave it in my setup. I will likely get a better set of interconnects though and see if I can tell any difference there.
I spent some time swapping it in and out of line in my system to see what it did sonically. For me, I thought that there was a barely perceivable loss of fine detail with it in line but I was sure so I had my daughter come and do some listening for me. She concluded that that is the case. It's very subtle but there is a little degradation there. I'm not sure how much is from the circuit and how much is from the extra connections in the line. Also, in order to ad it into my system, I had to use one set of interconnects that are lower quality than the rest so that may play a small part as well. All that being said, the sonic differences are small enough that, for me the functionality of the switch is worth it so I will leave it in my setup. I will likely get a better set of interconnects though and see if I can tell any difference there.