After upgrading my DAC to one with a balanced output (the Schiit Modius), I needed a new way to control the volume of my studio monitors. I also needed a way to split the XLR output to my headphone amplifier (currently the Rupert Neve Designs RNHP). I decided I wanted to move to a passive, transparent solution instead of keeping the unnecessary pre-amplifier in the signal path just to get volume control.
After doing a little internet research, I couldn’t find a product that did what I needed and looked how I wanted. There were a couple close ones on amazon, but they lacked the XLR connections I love. Plus, who couldn’t use another personal project? So I started putting together an idea for a stereo, balanced, XLR splitter/volume control combo box that would look good on my desktop.
I started with the core of the circuit, the potentiometer. I chose the alps RK27114: a 27mm, 10kΩ, 4-ganged, audio taper pot that is very well regarded (Coincidentally, I found out it’s the same one Schiit is using in the the Magnius, the companion amp to the Modius).
For the connections, I picked up Neutrik’s “A” series male XLR and “Combo A” female jacks so I could accept balanced TRS as well as XLR input.
When it comes to project boxes, I’ve come to like the extruded aluminum boxes from Hammond. They have a clean look and are generally easy to work in (as long as you buy the right size, I’ve got a couple extras lying around due to that particular error). I ended up buying the 1455T1601BK and cutting down the length to about 4″.
The last major piece I needed was the knob. I wanted something with a little weight and a decent size. I settled on a 25mm red anodized aluminum knob from Riverstone Audio on amazon.
It’s pretty basic, but here’s the diagram of the circuit.
So, I drilled out the case, made a mounting bracket to recess the potentiometer, soldered it up (3x due to some mystery short circuits…) and made sure it was working.
Only thing left to do was plug it in and start listening!
