Re: Stella ST459 motorboating
The fact that the motor boating varies with the volume control suggests that the instability/oscillation that is generating the motor boating is occurring in the stages prior to the volume control. So suggest that the other 3 HT supplies, i.e. the -1, -2 & -3 supply rails be checked for stable voltage and also oscilloscope checked (if available) for any abnormalities.
Is it normal with this model that you get sound in the Stop mode ? i.e. many models mute the playback amplifier in Stop mode.
David
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