Nagra
PREAMP II-S
Nagra PREAMP II-S pairs tube circuitry with five inputs
The stereo preamplifier offers selectable 0 dB and +6 dB gain settings. Its front-panel Modulometer displays both channels' audio levels. Power comes from an external supply, with support for Nagra's MPS and Classic PSU.
Georg S. Kuklick
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Nagra pairs vacuum-tube amplification with selectable gain in the PREAMP II-S. The stereo preamplifier uses two 12AX7/ECC83 tubes and one 12AT7 tube, with gain settings of 0 dB and +6 dB. It remains an active preamplifier when set to 0 dB.
The input connections comprise one balanced XLR input and four unbalanced RCA inputs. Balanced XLR and unbalanced RCA outputs are also provided, with a front-panel switch selecting between the two output types. The front panel houses Nagra's Modulometer, which displays left- and right-channel audio levels. The preamplifier's styling evokes the company's classic reel-to-reel tape recorders.
Specified frequency response extends from 10 Hz to 50 kHz within +0/-0.5 dB, while dynamic range is specified at greater than 125 dB with gain set to +6 dB. Output impedance is specified as 18 ohms at +6 dB gain and 9 ohms at 0 dB gain. Total harmonic distortion is specified below 0.01% at 1 kHz with a 1 V RMS output into no load. The specified crosstalk figure is greater than 85 dB, also measured at 1 kHz with a 1 V RMS output into no load.
The chassis has a phenolic damping layer beneath its aluminum top plate, and the preamplifier has a specified weight of 10.6 pounds. An external power supply connects to the PREAMP II-S through a LEMO connector. The unit can operate with an existing Nagra MPS or Classic PSU. Nagra began designing high-end audio components in 1997.
Key specifications
Product type | Vacuum-tube stereo preamplifier |
|---|---|
Tube complement | 2 × 12AX7/ECC83; 1 × 12AT7 |
Selectable gain | 0 dB or +6 dB |
Frequency response | 10 Hz–50 kHz (+0/-0.5 dB) |
Dynamic range | >125 dB at +6 dB gain |
Output impedance | 18 ohms at +6 dB gain; 9 ohms at 0 dB gain |
Total harmonic distortion | <0.01% at 1 kHz, 1 V RMS output, no load |
Crosstalk | >85 dB at 1 kHz, 1 V RMS output, no load |
Inputs | 1 × balanced XLR; 4 × unbalanced RCA |
Outputs | Balanced XLR; unbalanced RCA |
Power supply | External Compact PSU; compatible with Nagra MPS or Classic PSU |
Power connector | LEMO |
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