Hiss on left channel...except during load shedding.

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Ands

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Hi All,

About 2 months ago, I upgraded my B&W 607 S2's to a pair of 705 S2's.

I had hoped that the speaker upgrade wasn't going to prompt me to upgrade the rest of my rig, but life isn't quite so simple.

I had been running the 607s on a Rotel A12 integrated amplifier for 2 years without any issue. However, switching over to the 705s, I noticed a buzzing or hissing sound coming out of the left channel. Holding my ear up to the amp, I could hear a buzzing sound coming from inside.

I am using the 705s as desktop speakers. My desk is a converted dining room table, so I sit approximately 1 meter away from the speakers. The buzz is therefore quite audible at low volumes or when the music is paused. And yes, I find it annoying...

I also have a Marantz PM6006 hooked up in my lounge room. When I swapped out the Rotel for the Marantz, the 705s are dead silent. No buzz at all.

Since I run a B&W ASW610 sub from the pre-outs on the Rotel, the PM6006 was not going to work as a direct replacement since it has no pre-outs. In addition, the PM6006 has lots of detail and sparkle (which I absolutely love), but the midrange and low end is no match for the Rotel. However, when I listen to the Rotel, I miss the Marantz... Time for a new amp.

This weekend, I bought a used Marantz PM-KI Pearl Lite. I am truly blown away by this amp. It has all the detail of the PM6006 and more - but even better midrange and low-end than the Rotel. True audio bliss...

Except for one thing. The PM-KI Pearl Lite also has a buzz in the left channel. Not as bad as on the Rotel, but it's there alright. Like the Rotel, there is a soft buzzing noise coming from the amplifier itself. Again, only the left channel picks it up. The right is completely silent.

This morning, while we were running off batteries - there was no buzz coming from the speakers. The amp is dead silent. But as soon as the load shedding was over and we were running off Eskom again, yep - the buzz was back.

Could this buzz be caused by noisy capacitors? Does the Marantz maybe need a recap? Or could it be "dirty" power coming from Eskom? Should I rather be looking at upgrading the mains cable or perhaps even getting a power conditioner?

Cheers,
Ands

P.s. Apologies for the long post. Just trying to give some context.
 
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