The 5010B is technically identical to the 5010. They differ in width. While the 5010 fits the receivers with a width of 400mm, the 5010B has a width of only 416 mm and thus fits the individual components integrated amplifier, preamplifier and power amplifier. Another difference is the missing hexagon screws in the front, which should give the 5010 the same 'look' as the receivers. They are intended for the "rack handles" RHA-1 on the 5010, but are otherwise functionless. The thicker "rack handles" RHA-2 with adapter angles are required for rack mounting of the 5010B.
The 5025 has three knobs: Mic L + R / Line L + R (two smaller coaxial knobs left and center) and Master Level (larger knob, right). In addition, the 5025 has Peak Level Indicator LEDs. Mechanically and technically, it is identical to the 5010 and 5010B.
The 1820 / 1820 Mk.II is a parallel model of the 5010. It has smaller VU meters, flat, square drive buttons and a darker front side. However, the outer frame of the front is aluminum-colored. This makes it suitable for the MR-215 receiver, for example.