Hi guys,
I recently repair a Marantz NR1501 by fixing the so famous regulator capacitor problem
In fact i hear a very low continuous high frequency sound when no source is playing. Imagine the sound you think hearing when you come back, early morning, from a gig or the discobut very low ok !
Ioda
I have picked up a very clean one of these. Very pleased with it then settled down to use properly and noticed exactly what you describe. Apart from this the unit works well.
I have dug into the issue some. On stereo e.g FM tuner, there was clear high frequency sound with volume set to zero on L speaker, but not right. Following the schematics I re pinned internal connector to swap channels over into power amp stage, no change, stayed on the L speaker. So not appearing to be coming in on signal to power amp.
I repinned the amp output to swap channels and high frequency sound moved to R speaker. Seemed clear case of problem on L stage of power amp. Had a really good look at this but cannot change the symptom.
Testing further if you put amp volume to 1 the high frequency sound starts to emit from both channels. As you increase the volume, the noise itself does not increase in volume.
Feeling this may be related to the main power supply.
I took a recording of the sound, it measures as 1188 Hz.
In surround mode all channels have the high frequency sound even with zero volume. i.e. Interestingly L and R both have the noise at zero volume unlike when in stereo mode.
I recapped the HDMI board for common capacitors and checked others. All common ones measured ok but changed regardless. No change to symptoms.
So did you ever get anywhere with this ?
The unit sounds fantastic, really impressed with music playback in stereo.... but in surround, quiet movie scenes are ruined.
