The ST-10M Reference Class Mono Amplifier builds upon NuPrime’s fourth generation (V4) amplifier module from the ST-10 and brings it to the next level. The ST-10 was designed within the space limitation of its chassis and hence had a power system which was capable of providing 150W power output to each of the stereo channels. To really bring out the best of the V4 amplifier module, the ST-10M has a new 300W power supply for its mono channel. The entire design including the chassis has been optimized for the mono configuration, further lowering the cross channel interference.

Other Circuit Enhancements

The original 10A bridge rectifier has been replaced by a 50A Schottky diode, the capacitors upgraded 30,000 micro-Farad, and duly the power transformer is now rated at 300W. Improved circuit layout with careful component selection has allowed the ST-10M to have a lower noise floor than the ST-10.

The NuPrime Sound

The ST-10M sounds more full bodied and rich, conveys greater immediacy and power as compared to the ST-10. The improved power delivery and reduced interference gives the instruments richer overtones and more natural decay. The soundstage is deeper and creates a greater sense of space. Imaging gains more solidity over the ST-10 which already has an impressive placement.

The effects of the improvements could be heard on the following examples. The striking of piano keys demonstrates greater attack and faster transients, with a sound that naturally resonates with the piano body. Brass instruments sounds glorious, characterful and carries a natural sheen but not overly bright. Female vocals and high frequencies retains the signature of the ST-10 but is smoother on the ST-10M. In an ensemble, the tonality gains an extra notch of richness which makes the overall presentation more natural.

With the ST-10M, every aspect of the ST-10 sound has been improved upon, which makes it truly a reference grade amplifier!

Note: The ETI BP-20C binding posts used in current production have higher quality than the ETI Cable Pod binding posts used in older production batches.

• Inputs:
  • RCA: Un-Balanced input x 1
  • XLR: Balanced input x 1
• Outputs:
  • Speaker Out x 1

• Power Output (rated): 230W @ 8 Ohms, 320W @ 4 Ohms
• Power Output (peak): 270W @ 8 Ohms, 375W @ 4 Ohms
• Gain: x 28
• Input Impedance: 47k Ohms
• Sensitivity: 1.5Vrms to rated power
• Total Harmonic Distortion (THD): 0.01%
• Signal to Noise Ratio (SNR): 91dB @ 10W
• Frequency Response: 0Hz to 50kHz (-3dB)
• Rated / Peak Current: 10A / 18A
• Standby Power Consumption: 0.9W at 115V outlet, 1.7W at 230V outlet
• Idle Power Consumption: 14W at 115V outlet, 14.8W at 230V outlet
• Worldwide AC voltage: (115 VAC / 230 VAC) with Voltage Select Switch
• AC Fuse: Slow-blow, 5A, 250VAC
• Dimension: 59 mm H x 215.4 mm W x 394 mm D
• Weight: 6 kg
• Color: Black or Silver

ST-10M is a phase inverting amp. If you are certain that the +/- (usually the red/white connectors) phase of your inputs are non inverting, then you should reverse the +/- inputs for each channel on ST-10M.  All other NuPrime amps were designed as non-inverting amp.  If you have no idea what this is all about, don’t bother with making any adjustment.

There is no 12V trigger for ST-10M.