Descent sub transformer noise

I recently purchased a Martin Logan Descent sub and have a quick question to owners. When the sub is off I hear a slight buzz from the transformer. When the sub is on the transformer noise fades and is no longer present. Is this a normal characteristic of the sub or should I be concerned? Not a ground loop. No humming just a slight internal buzz when off.

Descent Transformer Buzz...

David O said:

I recently purchased a Martin Logan Descent sub and have a quick question to owners. When the sub is off I hear a slight buzz from the transformer. When the sub is on the transformer noise fades and is no longer present. Is this a normal characteristic of the sub or should I be concerned? Not a ground loop. No humming just a slight internal buzz when off.

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David,

Welcome to the ML Club!
No, your Descent should be quiet when it is off. I had this same problem when I first got my Descent a couple of years ago. IMHO, I think it maybe a Descent power cable positioning problem. What I did was moved the Descent's power cord away from my main speaker's bi-wire cables (Ascent i's). I had to raise the Ascent i's bi-wire above the Descent's power plug, they could not touch at all. I also had to plug the Descent into a separate power circuit, not the same circuit as my Ascent i's or Theater i's power conditioner. Give it a try. It worked for me. Good luck...

Oh that's just great. A $2,600 gremlin Thx for your post Robin. I hope this is not the case. Anyone else experienced this with a Descent sub and resolved in a different manner. I only have one circuit for my home theater available. My mains lines are close to the Descent Power cord because of the limited space available in my living room.

It's not as bad as all that....

David O said:

Oh that's just great. A $2,600 gremlin Thx for your post Robin. I hope this is not the case. Anyone else experienced this with a Descent sub and resolved in a different manner. I only have one circuit for my home theater available. My mains lines are close to the Descent Power cord because of the limited space available in my living room.

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David,

It's just a minor tweak really.... It took me about an hour or so with my son's help of course, and presto it was gone. I've hardly thought about it since... I really love the Descent subwoofer, as I know you will soon. Hang in there. It didn't cost me anything at all I just had to position things differently that's all... I think Roberto would agree with me on this. Give it the old college try.

HTH

Are you sure it is not a ground loop. They sometimes will sould like a buzz. If you have not tested it I would just to be sure. Subs(amps) are known to be a cause of it.

Robin said:

David,

It's just a minor tweak really.... It took me about an hour or so with my son's help of course, and presto it was gone. I've hardly thought about it since... I really love the Descent subwoofer, as I know you will soon. Hang in there. It didn't cost me anything at all I just had to position things differently that's all... I think Roberto would agree with me on this. Give it the old college try.

HTH

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Hola...gee, you got me here Robin...I think it is just a minor problem, and it is coming from the transformer itself. Sometimes, the plates of the transformer could be loose and this produces this kind OF buzzing...you have to find how to get to the Xformer that it is making the noise and tight the four nuts that secures the plates and the external cover...happy listening,
Roberto.

roberto said:

Hola...gee, you got me here Robin...I think it is just a minor problem, and it is coming from the transformer itself. Sometimes, the plates of the transformer could be loose and this produces this kind fo buzzing...you have to find how to get to the Xformer that it is making the noise and tight the four nuts that secures the plates and the external cover...happy listening,
Roberto.

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That's what I was going to say too, but couldn't understand why the X-former would buzz with no power. Is there a standby switch or something?

Not a ground loop. If so, the hum would also be present in the woofer when powered on. It would hum when the unit is on and not on standby. The amps transformer is silent when the unit is on. No hum, hiss or buzz. Perfect. Only when the amp sleeps does the transformer buzz return.

The transformer buzz occurs when the Descent is either in standby mode or off using the power switch on the face plate. There is a master amp off in the rear. This usually stays on unless you plan to vacation.

Robin, I plan to rearrange the power cables. Hopefully it is just picking up some transient AC line noise. I could always purchase a better shielded power cable.

descent

contact Jim Powers at Martin Logan before you do anything.

Descent Buzz...

David,

I Hope everything works out, when you reposition the power cables... As you are doing so, listen for the sound to go away when you think you have got it. When I moved the last touching point, the buzz immediately stopped...

I was just thinking, another possibility could be fluorescent ballast or a dimmer switch on the same circuit, which your Descent maybe, unwittingly plugged into as well.... Just a thought, as these types of devices may cause the buzzing of the internal amp on the Descent.

By-the-way ~ I just want to admit - Roberto is my personal savior, I just thought I'd admit it publicly... I love you Roberto.

I should mention that the transformer buzz can only be heard when I put my ear close to the enclosure. I could put this topic to rest if a couple of Descent owners could verify with the main amp power on (back of unit) and the front power switch off, do you hear a low buzz inside the enclosure. If not, Lexor how would one go about contacting Jim Powers at Martin Logan?

David O said:

I should mention that the transformer buzz can only be heard when I put my ear close the the enclosure. I could put this topic to rest if a couple of Descent owners could verify with the main amp power on (back of unit) and the front power switch off, do you hear a low buzz inside the enclosure. If so, Lexor how would one go about contacting Jim Powers at Martin Logan?

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If you disconnect the sub cable does it still buzz.

Yes with or without the sub cable. When the unit is on no buzz or hum completely silent. Only when I turn the sub off do I hear the slight buzz of the transformer. Again not through the woofer but within the Descent enclosure. I thought I was just being anal, but with no confirmation from other Descent owners of a similar characteristic I wonder.

David O said:

Yes with or without the sub cable. When the unit is on no buzz or hum completely silent. Only when I turn the sub off do I hear the slight buzz of the transformer. Again not through the woofer but within the Descent enclosure. I thought I was just being anal, but with no confirmation from other Descent owners of a similar characteristic I wonder.

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Bummer it is the sub and it would drive me nuts to. I can not believe it is normal, someone with the Descent chime in.

Just thinking loud Robin...

Hola...just thinking loud, the problem is when the unit is in off position...the buzz is coming from the inside of the cabinet, and not from the speaker, then we might have two power supplies working inside. One is the small power supply that turns on the power amp, (big power supply) when a signal is detected at the input, high or low impedance, this ssmall xformer is the culprit of the noise. Hope this can help to track the problem...happy listening...and I love you too Robin ...
Roberto.

My Descent does make a very slight buzz when powered up, but it is so faint that you would have to have up your ear up to the drivers to hear it. When the sub goes’s into stand buy it is completely silent.

Zip3kx07, do me a favor. Place your ear next to the blue M logo with the master power on (rear of sub) and the switch on the front panel set to the off position not auto. Listen and tell me if you hear the transformer inside the enclosure. Thx.

David O said:

Zip3kx07, do me a favor. Place your ear next to the blue M logo with the master power on (rear of sub) and the switch on the front panel set to the off position not auto. Listen and tell me if you hear the transformer inside the enclosure. Thx.

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Sure No prob, Davd. I am at work right now, I get off at 1:00am I will check for you when I get home.

David O said:

Zip3kx07, do me a favor. Place your ear next to the blue M logo with the master power on (rear of sub) and the switch on the front panel set to the off position not auto. Listen and tell me if you hear the transformer inside the enclosure. Thx.

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If I press my ear up against the front panel I can hear a very faint hum, it doesn’t matter if the switch is off, auto, or on it’s there. If I have the switch set to auto and I flip it to off, I do not get a buzzing sound.

Hope this helps.

OK guys,
I think I can help with this one. I had the same experiance with my descent sub untill I called ML direct. Try the following-it worked for me...

Go to any hardware store and buy a cheap (less than 1 dollar) ac adapter that will convert the 3 prong plug into a 2 prong plug.

It solved my buzz problem and it is easy/cheap to try. ML assures me that this will not have any adverse affects.

GL...Let us know,
Dominick