Krohn-Hite 7500 Wideband Power Amplifier, dc to 1 MHz

The Krohn-Hite Model 7500 is the first direct-coupled, wideband amplifier that offers extended output power and voltage capabilities, low distortion, an advanced, all solid state design, and performance features not previously available.

The Model 7500 provides more than 75 watts of continuous power (150 watts at dc), and 125V rms from dc to 100kHz. Frequency response of the 7500 is typically flat to within 0.05dB over most of its range. In addition, the 7500 typically contributes <0.05% of total harmonic distortion, at full power output, up to 10kHz. The voltage gain of the 7500 is non-inverting, and can be selected for either 20dB (10) or 40dB (100) of fixed gain, or continuously adjustable from 0dB to 40dB. The 7500 also provides either direct (dc) or capacitive (ac) input coupling.

• Frequency Range: DC to 1MHz
• Frequency Response: <±0.1dB
• Distortion: <0.1%
• Maximum Voltage: 140Vrms, OC
• Voltage Gain: 0dB to 40dB
• Variable DC Offset: 0V to 200V Peak
• Short-Circuit Protection

The Model 7500 is one of the few amplifiers on the market today that offers a combination of power, performance and versatility. Its power and voltage capability, low distortion and flat response, make the 7500 well suited for use in precision meter calibration, transducer driving, bridging applications requiring high input and low output impedance, and as a low distortion ac power source, when used with a suitable low distortion oscillator.

• Frequency Range: dc to 1MHz.
• Power: 75 watts, dc to 100kHz; 40 watts at 500kHz; 10 watts at 1MHz.
• Voltage: 125V rms, dc to 100kHz; 90V rms at 500kHz; 45V rms at 1MHz.
• Current: 625mA rms, dc to 100kHz; 450mA rms at 500kHz; 225mA rms at 1MHz.
• Frequency Response: Flat to within ±0.1dB, dc to 10kHz; ±1.5dB to 500kHz; –3dB at approximately 1MHz.
• Harmonic Distortion (at 75 watts into 200 ohms): <0.1% to 10kHz, approximately 1.5% at 100kHz.
• Voltage Gain: Fixed, 20dB ±0.2dB (X10) or 40dB ±0.2dB (X100), or continuously variable 0dB to 40dB.
• Gain Stability: <±0.001dB change for a 10% change in line voltage.
• Dynamic Range: >85dB.
• Phase Shift: 0° ±1° from dc to 10kHz. Phase shift increases linearly to 100° (lagging) at 1MHz.
• Squarewave Response (at 100Vp-p into 200 ohms): Rise Time: <600ns. Overshoot: <5%. Zero droop in dc coupled mode.
• Regulation: No load to 200 ohms, <0.5%, dc to 10kHz.
• Hum and Noise (1MHz bandwidth): <4mV rms with input shorted; <10mV rms with input open and shielded.
• Coupling: Direct.
• DC Level: Nominal zero volts.
• DC Offset (no load): Variable, 0V to ±200V. Combined ac plus dc offset limited to ±200V.
• DC Level Stability (After 30 minute warm-up): Vs. Line (short term): <1mV for 10% line voltage change. Vs. Time: <2mV/8hrs. Vs. Temperature: < 5mV/°C.
• Internal Impedance: <1 ohm, dc to 10kHz; <10 ohms at 100kHz; <80 ohms at 1MHz.