Sansui au 317 Amplifier DC Bias & DC Offset Adjustments

[@waynegram8907]

What does the DC offset adjustments do to the amplifiers Left channel and Right Channel? because if the left channel has a different DC offset point compared to the right channel has a different DC offset point, what happens?

[@MichaelYates]

The channel with the higher dc offset will signal will clip more than the other, sound more distorted and to high can damange speaker drivers. best to have both channels below 50mv with 25mv or less being good

[@waynegram8907]

@@MichaelYates Its adding DC offset voltage to the base or collector of the preamp transistors section or power transistor section? adding a +DC offset voltage to the AC signal/AC waveform will CLIP the the positive cycle or negative cycle of the AC waveform to the Power Supply Rail Voltage?

[@MichaelYates]

Hi, it is towards the end nearing the power transistors, a little video here on YT tells what DC offset is better than I can proberly explain kzbin.info/www/bejne/amHVfIBmp8ekm6M

[@martin-f5482]

that's geat, my 317 lost the left channel so I have to fix it, would you mind to let me know where you found the service manual?

[@martin-f5482]

found it already, thanks anyway

[@MichaelYates]

Pleased you found it

[@martin-f5482]

@@MichaelYates it's a 317 VII, no Bias voltage at the left channel, any idea?

[@MichaelYates]

@@martin-f5482 So zero volts no matter how you adjust the pot. Then I would check that you have around 42 volts one side or Resistor 47 and 41 volts the other side of it and the same with resistor 53 as manual indicates

[@martin-f5482]

@@MichaelYates thanks, there's no voltage drop on it, same value on both sides (47Vdc) R48 (the one for the right channel has the 1Vdc trop.