One reason for reducing the volume on non HDCD tracks was to deal with CDs that contained both HDCD and regular CD tracks.
The Oppo players implement HDCD and actually allow you to turn it on and off. Their HDCD implementation used to use a customized version of a Mediatek chip. I believe they are still using Mediatek for HDCD with the 103/105, but I have not seen anything that confirms that.
It is my understanding that the Oppo does not change the volume for regular CDs, but I have not tried it.
You might check with Oppo on the details. They are usually pretty good about answering this type of question.
The Oppo players implement HDCD and actually allow you to turn it on and off. Their HDCD implementation used to use a customized version of a Mediatek chip. I believe they are still using Mediatek for HDCD with the 103/105, but I have not seen anything that confirms that.
It is my understanding that the Oppo does not change the volume for regular CDs, but I have not tried it.
You might check with Oppo on the details. They are usually pretty good about answering this type of question.