I don't understand the aim of two rectifiers in parallel mode at it's input (both connected to the same secundary output of the mains transformer).
Additional the diodes D706-709/756-759 confuses me.
Thank you for claryfying of this topology.
The whole schematic you will find here:
SONY TA-F730ES Service Manual download, schematics, eeprom, repair info for electronics experts
wait several minutes until displaying the button "get manual"
BTW - sound quality is excellent after remove all contact issues inside of the pots and switches.
Maybe through high idle current in the output stages (4x 100mA @+/-60VDC - approximately 50 watts idle power at the internal heatsink)
Additional the diodes D706-709/756-759 confuses me.
Thank you for claryfying of this topology.
The whole schematic you will find here:
SONY TA-F730ES Service Manual download, schematics, eeprom, repair info for electronics experts
wait several minutes until displaying the button "get manual"
BTW - sound quality is excellent after remove all contact issues inside of the pots and switches.
Maybe through high idle current in the output stages (4x 100mA @+/-60VDC - approximately 50 watts idle power at the internal heatsink)
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I did not arrive at the complete diagram.
My impression is the two rectifier bridges serve to isolate supply voltage swings to two different consumers.
If one consumer-circuit causes the supply voltage to sag, the other consumer-circuit is not exposed to the reduced supply voltage if separate rectifier bridges are used. Thus, this way you obtain supply voltage isolation.
Due to the difference in power decoupling capacitor size (12000uF / 4700uf), the part decoupled with 12000uF could well be the power amplifier part and the other part (4700uF) used for various pre-amplifier circuits. The supply voltage swing on the power amplifier part is likely to be significant with a high output power level. You do not want this voltage swing to affect the performance of the pre-amplifier part.
The diodes D706-709 / D756-759 appear to prevent the upper supply part from retaining a high charge on the 4700uF capacitors if the voltage on the 12000uF capacitors drops too much (2x4x diode voltage drop). Why? Perhaps because, when the amplifier unit is turned off and the 12000uF capacitors are discharged through the power amplifiers, you do not want the pre-amplifier circuits to remain with tension for long.
My impression is the two rectifier bridges serve to isolate supply voltage swings to two different consumers.
If one consumer-circuit causes the supply voltage to sag, the other consumer-circuit is not exposed to the reduced supply voltage if separate rectifier bridges are used. Thus, this way you obtain supply voltage isolation.
Due to the difference in power decoupling capacitor size (12000uF / 4700uf), the part decoupled with 12000uF could well be the power amplifier part and the other part (4700uF) used for various pre-amplifier circuits. The supply voltage swing on the power amplifier part is likely to be significant with a high output power level. You do not want this voltage swing to affect the performance of the pre-amplifier part.
The diodes D706-709 / D756-759 appear to prevent the upper supply part from retaining a high charge on the 4700uF capacitors if the voltage on the 12000uF capacitors drops too much (2x4x diode voltage drop). Why? Perhaps because, when the amplifier unit is turned off and the 12000uF capacitors are discharged through the power amplifiers, you do not want the pre-amplifier circuits to remain with tension for long.
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