The first thing to strike the observer is the unusually high density of custom SCR polypropylene interstage and decoupling capacitors: 20 in total, with two of pepper mill diameter, all others stacked two up. This arsenal takes up so much space as to tightly circle the thermionic gain devices. As a result, those tuck into heat shields for safety. If ordered with the i/o balancing transformers like I did for my loaner to document this option, four 'big-watch' casings at twice a big watch's thickness cluster vertically against the back plate's socketry PCB. In fact, vertical boards are a theme due to the tightly packed innards.

There are two more such upright boards against each 2mm side wall; and one that cradles against one of the colossal caps [below]. All of these and the underlying motherboard show fat gold traces. Conventional hookup wiring is very minimal and ribbon cable connections are kept as short as feasible. My overriding visual impression was one of fastidious precision execution. Swiss made tends to promise that but not always delivers to this degree. The well-worn phrase "seeing where the money went" felt most à propos.

Here we look from the back at a quad of Nagra balancing transformers soldered shut inside Mu-metal shielding canisters. On the subject of balanced operation, Matthieu Latour let slip that at trade shows, Nagra always demo single-ended setups. After all, their gear isn't balanced even with transformer-generated XLR. Unless you already owned a fully balanced source and/or amp, it'd make no sense to outfit the Classic Preamp with costly balancing transformers expecting better performance per se. Put differently, someone assembling a system from scratch around this Nagra wouldn't consider balanced ancillaries.

Here is one of the side-wall boards, the 50kΩ motorized Alps Blue in stereo not 4-gang balanced guise at right.

To learn what sections of this circuit do what, we turn to Matthieu Latour for a guided tour.