Pioneer SX-1250 OVERVIEW

Pioneer SX-1250, The most sought after powerful stereo amplifier. To achieve this unprecedented power rating Pioneer developed the now legendary power section of the SX-1250 with completely independent power supplies, including separate power supply windings, rectifiers and smoothing capacitors for each channel, the components of which include a massive 22 pound toroidal core transformer (less susceptible to power fluctuations and less likely to create noise than laminated core transformers) and four ‘Coke Can’ size 22,000uf filter capacitors. The amplifier section was composed of a 2-stage differential amplifier and a Darlington push-pull amplifier for the final stage. All stages are direct coupled in a pure complementary OCL circuit that includes a current mirror circuit. This combination delivered FTC regulation measurements of 160 Watts RMS per channel into 8 ohms from 20-20KHz with no more than 0.1 THD and 200 Watts RMS per channel with 0.1 THD into 4 ohms.
The preamplifier section combines exceptional flexibility with superb sound achieved through utilising field effect transistors and CR type integrated circuits. The phono input has a 4-stage preamplifier equaliser with an RIAA correction of only +_0.3dB and a overload level of 500mV meaning no magnetic cartridge can strain the pre-amp. The designs of these sections were directly borrowed from Pioneer’s separate components.
Pioneer never manufactured a unit to match these specifications ever again and this is one of the many reasons purists believe that this model is the apex of high fidelity sound.

Specifications
Power output: 160 watts per channel into 8Ω (stereo)
Frequency response: 10Hz to 50kHz
Total harmonic distortion: 0.1%
Damping factor: 30
Input sensitivity: 6.5mV (mic), 2.5mV (MM), 150mV (DIN), 150mV (line)
Signal to noise ratio: 75dB (MM), 90dB (line)
Output: 150mV (line), 30mV (DIN), 1V (Pre out)
Speaker load impedance: 4Ω (minimum)
Dimensions: 556 x 186.5 x 464.5mm
Weight: 29.2kg