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Strange Oscillation

Alright, I need to get to the bottom this. On a couple of CD's at certain passages, the music goes into an oscillation and won't quit until the volume is reduced or the disc stopped entirely. My playback source is an Ayre C-5xeMP, Plinius Tautoro pre and Plinius SA-103 amp. Interestingly this only happens on a few CD's and usually when there is a sustained chord such as from a keyboard note that is held or a sustained vocal. Two examples are Pink Floyd, Dark Side of the Moon, track one about mid point with the EMI Japan release CDP746001 Z. I also have the MFSL issue and it plays with no problem. Another example is Patricia Barber, Cafe Blue standard redbook release during a sustained high pitch vocal note and only at high volume. So what causes this to occur? It is obviously related to the CD itself since DSOTM MFSL issue plays just fine. Can anyone enlighten me?
128x128falconquest

Showing 2 responses by kijanki

kijanki's avatar
kijanki
4,394 posts
 
I have Cafe Blue, standard CD and cannot hear any high pitch vocal.  In fact, it is the one of the best recorded CDs used for demo in many stores. Can you point to particular song, minutes, seconds?

Vibrapods might protect CDP from vibrating shelve, but will do the opposite when CDP body vibrates.  Did you try to remove them?

Perhaps laser is weak (dirty).  Try to clean it.
kijanki's avatar
kijanki
4,394 posts
 
Falconquest, I just checked - it is clean. I used high volume on headphones and speakers.  There is a lot of sibilants, more vivid with headphones, but still clean.  5:19 high voice note is very clean.  You could clean laser with laser cleaning CD.  I was suspecting time jitter of digital signal, that converts to noise, but it would shows in unpleasant sibilants first.  I suspect, that you have some system or room resonance at this frequency.  Try to eliminate things.  Is it tweeter?  Is it in both channels?  Can you borrow another CDP or rip it and play it from computer or the phone?  Better yet, can you take this CD to a friend?  
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