The HD AMP came from the need of bringing Nagra signature transparency into more powerful amplifiers to accommodate yet larger rooms and larger speakers.
The power supply goes to extremes to make sure the amplifier is stable and can deliver high power at any time. It is built around a 1600 VA transformer. In Nagra’s own tradition it is followed by a multiple diode stage and a very complex dual PI filter. This allows the amplifier voltage rails to be extremely stable. In addition, the current draw from the HD AMP is not polluted by impulse signals. So the rest of the set-up can perform at its best. The dual Pi filter acts like a protection shield between the HD AMP and the mains.
Each Nagra HD AMP unit features a bank of 264 mF of custom-made Mundorf condensers. They are the reference in their category and you rarely meet them in this quantity because most manufacturers consider them too expensive. We have chosen them after many hours on the test bench and numerous critical listening sessions.
The Nagra HD AMP audio amplification stage is relatively simple in its conception; this is in part what makes it so transparent and direct. Actually, each stage has been tuned to reach striking results. The driver stage for instance features numerous decoupling capacitors of different technologies. It has a very low output impedance to make the most of the power MOSFETs that follow.
Like all its famous predecessors in Nagra range, the HD AMP, uses MOSFET, field effect transistors. They are the closest thing to a valve triode and you can definitely feel its sonic character: direct, fast and musical. The HD AMP has precisely matched clusters of MOSFET, to insure the purest reproduction.
The Nagra HD AMP is fitted with a traditional Nagra Modulometer on the front panel, showing the output power.
30 W pure class A, 1000 W RMS on lower impedance
30 times winner of BEST SOUND OF SHOW at high-end audio equipment conventions in the past two years.
The Sky is Crying, the latter recorded when he was perhaps 66 years old, blew me away. The intimacy of the recording, the huge contrast between the man's aged speaking voice and still intact, surprising sweet singing voice left me breathless.
Jason Victor Serinus, Stereophile
sounded truly wonderful—beautiful, majestic, and very full-range.
Jonathan Valin, The Absolute Sound.