Denon POA-6600A - Crackling noise when idle

[albrechtv]

Hi all,

I own a Denon POA-6600A amplifier and this amplifier produces a crackling noise when idle (no audio source connected, not touching anything). Attached to this post I have included an audio-recording of the malfunction (a zipped mp3-file), and I'm curious if anyone has encountered the same crackling noise and could tell me what the problem is.

Does anyone have an idea what could cause this noise?

Many thanks in advance!

Albrecht

 

[Mark Tillotson]

Bad solder joint, intermittent connection in a connector, cracked PCB track, bad resistor, many possibilities, all variants of the same issue, intermittent connection.. Prodding with an insulated stick or using freeze-spray are methods to track down which area is responsible. However if you aren't sure about working on a powered on unit you might want to play safe.

 

[rayma]

Best to take an amp like that to an experienced tech.
Not simple to resolve.

 

[xtechee]

Sometimes static electricity will build up on the chassis, If the power cord has 3 prongs, then this is not the problem.
Otherwise, with a 2 wire cord, there should be a capacitor in parallel with a large value resistor(4.7 to 22M ohms) in parallel between
the metal chassis and the neutral wire on the power cord(the wider prong on the power cord)
Hope this helps.
xtechee-Mike

 

[newvirus2008]

Does anyone have an idea what could cause this noise?

Not sure, but it could be any of the power supplies for example, the ones feeding DACs / opamps. Poor earthing / shielding can also result in stray voltage pickup and feedthrough.

 

[huggygood]

I have worked several times on these amps (A and non-A) and I can assure you that they require at least a complete repair of all the soldering and a replacement of the small value capacitors.
If you are not competent in this matter, entrust them to a recognized professional.

 

[rayma]

Otherwise, with a 2 wire cord, there should be a capacitor in parallel with a large value resistor(4.7 to 22M ohms) in parallel between
the metal chassis and the neutral wire on the power cord(the wider prong on the power cord)

That is usually called a "death capacitor" for good reasons.