Improving a classic.
Going back to the Classic's pater familias means their venerable PL-P. In 1997 it was Nagra's very first consumer product. "Designed initially as a high-quality battery-powered vacuum tube preamplifier for vinyl records", of its eight tubes one 12AT7 and 12AX7 were assigned to the phono stage, two 12AT7 and four 12AX7 handled the line-stage gain. A-weighted SN/R was 100dB, bandwidth 22Hz-60kHz +0/-1dB and output impedance 60Ω. By 2001, the simplified PL-L omitted the phono stage and battery supply. It was down to today's 2 x 12AX7 and 1 x 12AT7 and already offered 4:1 RCA/XLR inputs. The Jazz superceded it in 2012 with 10Hz-50kHz (+0/-0.5dB) bandwidth, >112dB of dynamic range and output impedance of 50Ω based on the same tube complement. The Jazz also became the first consumer Nagra to abandon the pro-derived convention of locating its i/o on the left/right cheeks. Instead it moved the lot to the rear where all hifi competitors have theirs. Honouring legacy whilst modernizing for continued relevance is tricky business.

From our short survey we learnt how Nagra's core tube linestage circuit bowed in 2001 with the PL-L; how through the Jazz and Classic successors its complement of three dual triodes remained unchanged whilst specifications continued to push the envelope; how the headfi output skipped two models after the PL-P only to reappear in the Classic. We also noted the lengthy 11-year run of the PL-L as example perhaps of arch-conservative management and getting it right the first time; and the comparatively short 4-year rein of the Jazz introduced in the same year that Nagra Audio reorganized under new ownership.

With our time line established, readers will want to know about the key tech whereby the Classic pushes beyond its Jazz precursor yet does so without the HD Preamp's dual-mono attenuation transformers, ultracap power supply and complex mechanical isolators. Getting answers meant going back to my source, Nagra's manager of global sales, Matthieu Latour, descendant of a famous family of French winemakers.

In Nagra's growing Classic lineup, there are no tubes except for this preamp. Meanwhile it's valves galore in the HD DAC, HD preamp, 300i, 300P and VPA. The pyramid monos and later MSA amps were always based on transistors. So are the high-power HD Amps below; for obvious reason. With their expanding portfolio, Nagra of 2018 have more tube and transistor models. That the latter remain informed by their founder's love of glowing bits shows in this quote from the Classic DAC manual: "...a 9-Fet design topology [to] emulate the sound of a tube providing a particularly warm and musical sound". With the Classic Preamp, transistor systems benefit from an injection of pure tube virtues without introducing arcane tube bias rituals or strategic load matching of speakers to amp. These tubes will never see a wildly variable speaker impedance with back EMF. All the Classic Preamp tubes will ever encounter is the stable input impedance of whatever amp it drives. Even headphones aren't driven tube-direct but with a solid-state current buffer behind the valves. That combines tube tonality and staging with the low impedance, low noise and drive of transistors.

Nagra's system at the Warsaw stadium showcased the size difference between their Classic and HD components.

From Jim Saxon's CES 2017 coverage for "...recently, something has happened at Nagra. For the first time, their equipment revealed the tiny inflections, the filigrees and fractals—the texture—that gives reproduced sound a hint of reality. The difference between the dCS/Wilson/D'Agostino room and the Nagra/Wilson demonstration was the silence of the loudspeakers on Nagra electronics. It was as if the Alexx towers were on silent display and the music just arose at the front of the room. In two decades of covering the CES, I have never heard a system where the speakers weren't there. Though Nagra's technology is now available for a king's ransom, one hopes it will eventually trickle down." That trickle-down is the Classic range.