NAGRA BPS Bipolar Phono Stage
I am offering my ultra-compact, battery powered, bi-polar phono stage - NAGRA BPS. Its sound is accurate, lively, uncolored and absolutely dead quiet. Reviewed by Stereophile, 6 Moons, TAS, Tone and others. The BPS provides 64 dB of gain and is Stereophile Class A rated.
The BPS is driven by a single 9-volt battery. The electronics are assembled on two sides of a single motherboard and use discrete military-specification components, matched bipolar transistors, audiophile quality capacitors, and MELF resistors. The Moving Coil input transformers are designed and wound by NAGRA. The BPS is supplied with six adaptive loading circuits built onto six small modules. Your choice of module allows the input impedance to match virtually any cartridge.
The BPS is packed in a clever black plastic carrying case that also holds a spare battery, six loading modules, two Allen wrenches, owner's manual, and factory testing results. The BPS should be left ON for best performance. I will provide a wall wart with a long DC cord that, when inserted into the BPS's external power socket, will keep its circuits ‘busy' until you listen via battery power.
Frequency Response: 20 Hz (+1dB) at 30kHz (0dB) RIAA conform
Harmonic Distortion: <0.15%
Signal-to-noise ratio: > 77 dB (ASA A)
Channel separation: Typically 60 dB
Input circuit load: 47 k ohm without a load module installed
6 Loading modules: 100 (installed),150, 220, 330, 470, and 1 k ohm
Transformer gain: (MC input) Ratio 1:3.54 (+11 dB)
RIAA stage gain: 53 dB
Total gain: 64 dB
Output level: 2 V
Correction norm: RIAA 1953
Power consumption: 70 mW
Power supply: 1 battery 9V type 6LR61 (PP3)
Estimated battery life: Approximately 100 hours
Input connections: RCA-Cinch (gold-plated)
Output connections: RCA-Cinch (gold-plated)
Ground connection: Threaded stud with lock washer and nut
Weight: 16.9 oz.
Dimensions: (W x L x H) 4 1/4" x 6 1/4" x 1 1/8"