PRIMARE hfe primare a32 power service en free download

File name hfe_primare_a32_power_service_en.pdf

PRIMARE A32 Power Amplifier Service Manual 1. Technical Description. 2. Error codes. 3. Bias Adjustment. 4. Schematics. 5. Technical Specifications. A32 Functional Description Features The Primare A32 power amplifier is a fully balanced design, this means that the negative speaker terminals are active, not ground as on an unbalanced design. When performing measurements, test equipment (such as Audio Precision) that can handle balanced amplifiers must be used. The input impedance is 15K and the gain is 26dB. It is possible to obtain just above 250 undistorted watts at an 8R load (both channels driven). The frequency response are flat, the A32 will drop down only -2dB at 100Khz. Standby The A32 is equipped with two standby modes, where standby mode 2 is the power save mode. In power save mode only the standby circuit will be powered by the small standby transformer placed on the digital PCB. Digital control and monitoring When power is first applied and the standby button on the front panel are pressed down the A32 are going to initiate the startup sequence. Relay K1 will be turned on where after a small delay will follow before relay K2 goes active to disable the inrush limiters. At the same time bias are turned on by shutting down the voltage supplied to the optocouplers on the amplifier channels. After a 20 second startup delay for the amplifier to settle down the speaker relays are turned ON. During the startup sequence all safety parameters such as DC-offset and fuses will be monitored, if an error is spotted the amplifier will refuse to start and the standby LED will flash rapidly to indicate that an error has occurred. The error code can be read out by pressing the error check switch (SW1). Description of the error codes can be found on the next page. If the standby switch is pressed when the amplifier is in operate mode it will go to standby mode 1, which means that bias and speaker relay will be switched off. The standby LED is going to half light intensity to indicate that the amplifier is in this standby mode. If the standby button are pressed down for more than one second the amplifier are shutting down into standby mode 2 which means that bias, speaker relay and the two power relays K1, K2 are switched off. Only the standby circuit is still powered consuming just a few watt of energy. Temperature protection When temperature has reached 70 centigrade at the temperature sensors the speaker relay and bias are going to be switched off, when the temperature have decreased 10 centigrade the A32 are going to be restarted. In practice this will mean that the warmest part of the heatsink will be around 75-80 centigrade when over- temperature protection cuts in. General Protection During operation mode DC-offset, fuse, temperature and AC-loss are constantly monitored, any abnormal function from these will immediately disengage the speaker relay and the standby LED will start to flash rapidly indicating that an error h