Balanced signals offer some real advantages, such as lower noise and easy phase reversal. The problem is that most home-audio equipment is unbalanced in design. If you only see RCA jacks, then the gear is unbalanced. To connect a balanced signal source to an unbalanced one a bridge is needed between the two types of signals. A signal transformer is such a bridge, but an electronic solution also exists. Like the original Unbalancer, the Unbalancer-Two circuit accepts a balanced input signal and delivers an unbalanced, single-ended output. Besides performing the conversion from balanced to unbalanced, the circuit provides a little gain (usually, about 1.7 or +4.6dB) and exhibits an exemplary CMRR (Common Mode Rejection Ratio), which means that it largely ignores common-mode signals, in-phase signal shared between the balanced pair of signals, such has in-phase hum originating in the signal source or induced into the balanced cable.
The Unbalancer Two's low gain makes it much closer to the signal transformer. In fact, much like a 1:1 signal transformer, the Unbalancer Two can also accept an unbalanced input signal at either its inverting or its non-inverting input. Of course, the inverting input will invert the input signal at its output, while the non-inverting input won't.
The Unbalancer PCB requires two external power supplies, one for the high-voltage B+ and a low-voltage regulated power supply for the heaters. The high-voltage power supply can be unregulated, as the PCB holds an RC B+ filter in both channels to smooth away ripple. The GlassWare PS-1, PS-3, and PS-4 are good matches for the Unbalancer Two.
The GlassWare Unbalancer Two 9-pin stereo PCB is extra thick, 0.094 inches (inserting and pulling tubes from their sockets won’t bend or break this board), double-sided, with plated-through heavy 2oz copper traces. In addition, the PCB is lovingly and expensively made in the USA. The boards are 6 by 7.5 inches, with five mounting holes, which helps to prevent excessive PCB bending while inserting and pulling tubes from their sockets.
This kit includes all the capacitors, including six CDE 1kV polypropylene coupling capacitors, PCB, resistors (with many redundant values), five standoff assemblies with O-rings and screws, and four ceramic tube sockets. No tubes are included in the kit. The Kit includes a 16-page user guide. The Unbalancer Two user guide is 16 pages long and lists many design options.