Little Bear MC104 Pro Mini Audio Switcher, 4-Way 3.5mm AUX Stereo Passive Selector, Switch Box Splitter for PC/Player/Headphone/Amplifier/Speaker

For the current price of about $25, this is a fun piece of gear. It's comprised of 3 circuit boards (the bottom being for structural integrity only). Very simple build with an open frame, no chassis, very fun vibe similar to DIY MIDI project kits, but it's ready to go!The 4 rectangular pushbuttons are labelled with geometric shapes reminiscent of a video game controller, while the 4 buttons themselves are mutually exclusive, only 1 selection at a time, no combining of signals. Musicians may be reminded of the BOSS DC-2 Dimension C (vintage version) pedal, with a similar button arrangement. As on that classic pedal, these buttons CAN be latched down at the same time to combine them together if you've got just the right touch, but that's not officially supported of course! Mute button is handy but I don't use it much myself. I love that them went with a fun, round, red button for this.I love the looks of this unit. I have a coily red AUX cable plugged into it and it's a vibe. It's really small as well, smaller than it seems in the photos. Comes with 4 rubber feet to stick on the bottom. Fully passive. I use it to select between synthesizers going into my audio interface in my mostly 3.5mm stereo TRS based home studio. I assume this could also be used to switch between TRS MIDI signals as well, or 4 mono balanced signals, being a fully passive box. Even just to choose between your boring phone and boring tablet on the way into your boring desktop speakers, this little switch has the funnest appearance of any on Amazon. If you like big knobs they have another model with a rotary switch and volume control that're just asking for googly eyes to be glued to themIf you're a clumsy drink spiller or operating your equipment in a sand and/or dust storm, you may want to choose a more enclosed model of switcher.I haven't tested yet to see if the rear output is disconnected when the front output is used (like if you plug your headphones into the front, does it cut off the signal going to your speaker out the rear output, or are they both always connected?). I only use one output port at a time.If this was $50 I would feel a bit robbed, but at $25 it's a charming little gizmo.

As other have said, this is made with a couple circuit boards separated by standoffs and no case. The only issue with not having a case, is that I think after a while it will get dusty and dirty inside. It is small, but that is what I wanted. I did not need something to take up much desktop space. My application is simply connecting the output from my PC to several different audio sources. I run various applications that benefit from different audio amplification systems from headphones to Tanoy speakers. This device makes it easier to switch between them. I only need it to go to one source at a time so not being able to select more than one for output is not an issue. For what it cost, it was probably cheaper than having to go out and get the parts and make one myself. While they seem to work fine, I am a little concerned about the quality of the switches. They seem to be sturdy enough, but I am not sure how well they will hold up from repeated use. Time will tell. Until then I rate it upon current functionality.

The device has no case and is constructed as a stack of circuit boards separated by standoffs, spacers and screws. The components are exposed, which is part of the appeal of the unit for my use and taste. The button assembly allows only a single button to be depressed at one time, connecting the common jack to one of four output/input jacks. If you plug a device into the single front-facing jack, it becomes the common jack, bypassing whatever is connected to the common jack at the rear. This very convenient, as it allows hiding cords at the rear, while allowing a headset or other device to be plugged in without moving the unit. The red button disconnects both the front and rear common jacks from the selected output jack. It can act as a mute switch and is very handy.My application was to switch DC low voltage levels (a Morse code ham radio “paddle” using a 3.5mm stereo plug) through the box to one of four ham radio transceivers. I discovered a feature of the unit that caused the unselected radio to continuously transmit. The designer include two hidden 220 ohm surface mount resistors for each of the 5 input/outputs. The box connects the tip and ring connections of any unselected jack to ground through these resistors. This was probably done to place a load on any unselected audio device to avoid damaging it if unselected, a good precaution. For my application, the resistors were activating the unselected device by grounding the connections through them. My solution was to disassemble the unit and remove the hidden chip resistors with a small soldering iron. After doing so, the device functioned as I expected. Note, for normal audio applications, this probably does NOT need to be done. The unit was very easy to take apart and reassemble due to its design.I noticed a great deal of soldering flux residue on the board that had not been cleaned off. This was hidden from view and probably did not affect operation, but I cleaned it off the board with a cotton cloth and naphtha solvent, being careful not to get the dissolved flux into the switches or jacks. This should have been done during factory assembly, but likely omitted because of the danger of contaminating the switch assembly and jacks.