The non-sound version of the Russian Decapod that I had now for about 4 years (which was converted to DCC) runs very well.  Recently, I acquired two copies of the DCC/sound version.  They both have a rather pronounced background "whine" coming from the sound system (it is absent when I turn of the sound).  My Spectrum 2-8-0 (w/ sound) does not have this problem.  Is there anybody who encountered this problem before, and is there a solution?

Many thanks for any help you can give

Joachim