Cabinet resonance problem with Marantz MM9340 amplifier


The MM9340 amp is a four channel Class D amplifier producing 275W into 8 Ohms and 400W into 4 Ohms. I am using it to drive four subwoofers, which it can drive with ease. The problem is, the cabinet resonates seriously and appears to be in beat with the music. It does not appear to be airborne related nor is it originating from the stand. The resonance appears to generate from within the amp itself. Has anyone experienced a similar problem such as this? Any suggested solutions?

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Showing 5 responses by mrdecibel

Do you feel you can pop the cover, and while it is powered on, determine if there is a particular area within the amp, the vibration is coming from ? If you can, I believe I can help you. Where are you located ( city ) ? According to the web, the Marantz mm9340 weighs in at under 45 lbs. Dynamat, Peel & Seal ( roofing repair tape ) and others can be used to control resonance and vibration within every chassis. I dampen everything, and believe you me, the sq improves every time.

Yes, I have used Peel and Seal with excellent results. It bends around corners, is more pliable and easier to apply in many situations vs. Dynamat. But, I like Dynamat very much. There are other things available as well.

Although I am on a dedicated circuit, I own a particular Hafler designed amp ( Smart Theater Systems TA 242 I acquired from a going out of business movie theater ) that uses a toroidal transformer. When connected through my system, the transformer " hums " when I am using my OTR microwave. From the chassis only, not through the speakers. Yes, I damped this chassis and isolated the transformer using a few layers of Peel and Seal, and the hum is much lower, but I can still hear it. I suppose I can stop the humming by teaching it the words.......not my joke....Enjoy !