Circuit details continued:
• Low power standby feature
An additional small standby transformer, reduces power consumption in standby-mode.
In case power is switched on, the control line LOW_PWR_CTR is high → relay 1210 is activated → contacts 1 and 2 are
closed → transformer 5001is connected to mains.
When the set is switched off (standby) the control line LOW_PWR_CTR is low → transistor 7203 blocks → relay 1210 is
not activated → mainstransformer is disconnected. Via standby transformer and rectifiers 6210-6214 the supply voltage
LOW_PWR_SUP is substituted. This voltage is always available and so the microprocessor is kept running.
• DC voltages +A1, +B1, +C1
These voltages supply the Super Class G amplifier, described on previous page.
The whole power supply is optimized for the special characteristic of this type of amplifier. For that reason several “tricky”
details have been applied to ensure optimal efficiency and symmetrical load to the mains transformer.
Generation of +A1
Common full wave rectifying with bridge rectifier 6202, using 100% secondary winding of mains transformer (pin 10-14).
Generation of +B1
The supply for +B1 consists of one full wave rectifier:
– 2 diodes of bridge rectifier 6202, with 6200, 6201 for generation of +B1 using approx. 70% secondary winding of mains
transformer (pin 10-13 respectively pin 11-14).
As example for generation of +B1 see picture 1.
Generation of +C1
Full wave rectifying with 2 diodes of bridge rectifier 6202, using 50% secondary winding of mains transformer (pin 12-14/12-10).
See picture 2 below.
11-2 11-2
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