I've a stereo receiver / cassette / turntable SABA model CT-9810. It always had a problem with its digital volume control not allowing low volume levels. It has 16 levels of volume and the first level, the lowest one sounds like normal volume, second is quite high and higher levels too loud for any use.
The problem was "fixed" many years ago by adding a 56 ohm resistor in series with each loudspeaker however I am not really sure this is the right solution. Does anyone have its manual or service manual, does it mention something about that? Any similar experience?
I've gone inside and took some measures. Output amplifier is LA4280 which according to datasheet has an inbuilt gain of 100 and is supplied with 32V. Implemented circuit is identical to datasheet. Sound comes from a pair of LC7533 digital volume controls which are feed with a measured 1Vpp audio signal from the equalizer and they correctly adjust from 1/16Vpp to 1Vpp.
The output amplifier gain of 100 seems excessive to me, a 1Vpp signal at full volume becomes 100Vpp, which is obviously badly clipped at32V. 1/16Vpp (min volume) is 6Vpp output to the speakers.
For now I reduced LA4280 gain to 30 by adding 680 ohm resistors in series with the Feedback pins. But I still wonder if it rings a bell to someone.