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Marantz MA500 monoblock has serious hum. Hum decreases about half when external case is touched by hand. Changed subwoofer out line to mono amp; made no difference. Other mono amp MA500 does not hum. It never use to hum but did mix some rockford fosgate 8" subs that were miss matched. What can I do to remove the hum; anything?

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  • 31 Answers

SOURCE: Rockford Fosgate Problem in Nissan Titan

some decks save different settings on different sources. Make sure that the bass settings are not up higher on the radio sources and lower on the CD sources.

Posted on Mar 30, 2008

  • 17 Answers

SOURCE: No sound from Sub Pre-out on Onkyo TX-SR606

Also, it could possibly the preout terminal itself that is not working. One way to prove that is by transferring the subwoofer cable from the preout and temporarily transfer it to the tape out section. If it ouputs sound from there, then that means the speaker and the cables are working fine and it's just the preout terminal itself that is not picking up anything. ^_^

Posted on Dec 16, 2008

  • 1 Answer

SOURCE: Kube 2 subwoofer hum

The Kube Sub-woofer is earthed via its 3 pin plug. The Onkyo and other components I have in my system are not (they are double insulated). During normal operation, a difference in electrical potential can exist between these components in the system. I found that this potential was finding a path to earth via the audio cable and on through the subwoofer's earth. The path was via the earth portion of the audio cable and so gave the hum irrespective of volume levels set either on the Onkyo or the sub.

The fix is to ground the Onkyo to the sub. I used a length of electrical cable between a panel mounting screw on the back of the sub and a screw on the casing at the rear of the Onkyo. Try it out with a piece of cable manually touching screws with the bare ends of the cable until you find ones that give continuity( the hum will go immediately). I then crimped a small fork end electrical fitting onto each end of the cable which can be slid under the slighly loosened screw head and resecured. All I hear now is the fan on the Blu-Ray player!

Posted on Mar 12, 2009

dunnbiker
  • 8546 Answers

SOURCE: I have a Boston Acoustics

I'm thinking you have an open shield ground on the RCA input side. Connecting speaker inputs possibly restores the ground. Try connecting the high level inputs then disconnect the remote end of the cables (floating the grounds).

Then get out an ohmmeter and find that open circuitor or bad solder joint between RCA ground and real ground in the speaker's amplifier. Or.... if speaker ground kills the hum and you want to use RCA Line Level input to the sub, just connect one minus speaker output on your source amp to one minus on the sub's amp.

Posted on Mar 01, 2011

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I'm looking to connect a Marantz SR5001 to a Subwoofer, and there is currently no soundcoming through the sub.


On the SR series, you should find the setting for this in the setup menu on your remote. It will be easiest if you have a TV connected for video display. On the remote hit Amp -> Menu -> Speaker Setup -> Manual Setup. This should allow you to set the 'Subwoofer' setting to Yes. The subwoofer will need to be plugged in. If the setting cant be changed, try plugging in the Audassey microphone and run the calibration program which should detect the sub if its plugged in.

Jan 25, 2016 | Marantz SR5001

1 Answer

The subwoofer output on my Kenwood VR-606 has suddenly stopped working. I have tried the "setup" several times, turning the subwoofer off and back on. Also, when I first power up the system, it emits a low...


It sounds like the problem is not with your VR-606. If you hear a hum from the sub, the problem is more likely to be in the sub's built-in power amplifier. However, it is worth resetting the amplifier to factory presets. To do this, unplug the power cable from the mains supply and reconnect whilst holding down the power on/standby key. If the hum persists, connect any powered speaker to the sub-out socket, power on and listen for the hum. If no hum then suspect the powered sub amp. Turn the sub on with no connection to the Kenwood VR-606. If hum persists, the sub has a problem and will need to be replaced or repaired. By the way, you said there is a low frequency hum through the 'speakers' for about 30 mins. Is that all speakers or just the sub? Hope this helps.
Cheers, Don.

Jul 06, 2014 | Kenwood VR-606 Receiver

1 Answer

Loud hum from subwoofer


The number-one cause of subwoofer/speaker hum is the coaxial cable connecting your cable or satellite receiver to your provider (either through an inground run to a cable box or through a satellite dish). Here is how you test for this:
  1. Turn your system on and get it to produce the hum by watching a movie. Pause your DVD or videotape so that the hum is all you hear.
    TIPDon't use a normal cable or satellite program for this; you're about to disconnect the cable that provides the audio and video for your cable/satellite feed.
  2. Find the coaxial cable running from your cable or satellite receiver to your service provider, and while listening to the hum, unscrew the connector and disconnect the cable.
Did the hum stop or reduce by a large amount? If so, the cable you disconnected is the source of the noise. If this is the problem, you have several ways to fix the issue permanently (if not, jump ahead to the next section):
  1. Call your cable or satellite company and ask for a service call. Sometimes you get a smart cable guy, and if you demonstrate the problem he can do something upstream to ground the coaxial cable and remove or reduce the hum.
  2. Buy a power strip that has F connectors as part of its surge protection. Plug the strip into the AC outlet and feed your main coaxial signal through these connectors. This ties the shielding of the coax (the source of the noise) to your AC ground and sometimes can solve the problem.
    WARNINGOddly enough, this solution (surge protection) can sometimes increase the humming.
  3. Go to your local RadioShack store and buy three inexpensive items: a Matching Transformer (part #15-1253), an Indoor/Outdoor Matching Transformer (#15-1140), and a Cable Coupler (#278-304). Connect your coaxial cable to the cable coupler, and then to the first matching transformer. The output is two screws for the old two-wire antenna wire. Your indoor/outdoor matching transformer has two connectors for the screws, and the other end is a coaxial connector. Hook your cable or satellite receiver into this connector and see if the hum goes away.
Here is why this trick works: the first transformer converts your 75-ohm coax into a 300-ohm antenna connector. The second transformer converts the 300-ohm back to a 75-ohm connector. The humming, which usually is at around 60 Hz, can't pass through these conversions.

Ground Loop Hum

The second cause of hum is called a ground loop, and it almost always shows up right after you bring home a brand-new, self-powered subwoofer, or perhaps an external amplifier.
Take a look at all the plugs on the power cords on your home theater equipment. In most systems, the receiver (or amplifier) has a three-prong power plug, but most of your other devices have only two-prong plugs. This is not by accident; the device with the three-prong power plug is grounded. This means that device "owns" the ground. As long as no other power device has a three-prong plug, everything works well.
When you bring home a self-powered subwoofer and plug it in, though, you might notice it has a three-prong plug; this is for safety reasons. However, when you connect an RCA cable from your receiver to your subwoofer and turn everything on, you suddenly notice a loud hum.
The external amplifier in your subwoofer is now fighting with the amplifier in your receiver for possession of the ground. Both devices want to define 0.00 volts. But because the wiring in the two amplifiers to your household AC ground is different, one device is really using 0.001 volt and the other device uses something closer to 0.003 volts. The subwoofer cable connects the two, and the fighting begins.
You have to stop these two devices from trying to own the ground, or get them to not "see" each other. First, make your system produce the humming noise. Disconnect the single RCA cable between your receiver and subwoofer. Did the noise stop? If so, you have a ground loop issue.
The proper, safest way to solve this problem is to buy a special subwoofer cable with little arrows on the wire to show the signal direction (see ).
[img src="http://oreilly.com/images/hacks/htheaterhks/figs/htheaterhks_0601.jpg">
Figure 1. Subwoofer cable with directional arrowUnfortunately, many people have been ridiculed when asking about these sorts of cables at their local electronics store: "But cables don't really have a direction. My expert friend at work laughed at me when I asked about this!" Yes, your friend is right. Cables don't have a direction, but these little arrows indicate that this cable will prevent or solve your ground loop problem.
Remember when I said the hum started when you connected the RCA cable? That RCA cable really contains two wires: the center wire and something called the shield. The center wire carries the audio signal, but the shield tries to define 0.00 volts. The shield is the wire that lets the two different components (the receiver or amplifier, and the subwoofer) see each other's ground, and causes the fight. What if you took your subwoofer cable and disconnected the shielding from just one end? Wouldn't that solve the problem? Yes, it would. This is exactly what a subwoofer cable with little arrows does. The shield is not connected at both ends. The shield has to be connected at one end, for connecting to your receiver or amp, so you should run the cable so that the arrows show the flow from the receiver to the subwoofer.
WARNINGIt is unsafe to use a two-prong to three-prong "cheater" plug on the subwoofer power cord to solve the hum problem. Even if the subwoofer came with a cheater plug in the box, it's REALLY not safe to do. Don't do it.

Sep 01, 2013 | Denon Audio & Video Receivers

1 Answer

Hi There, I have a Marantz SR7005 Receiver and Bose 901 Series VI speakers with the Bose equalizer. I'm struggling to figure out the best way to connect the Bose equalizer/speakers to the SR7005. ...


It sounds like you've read one of my many posts on 901 deployment in the AV world.

Functionally, what is the difference between one amp with 'x' channels or 'x' mono amps? Nothing. Pre-outs don't know or care what else an external amp does.

According to this link http://www.ecoustics.com/electronics/products/new/642968.html those amps are 2- and 5-channel, respectively.

There was a time when I had two bridged-mono Carver Cube atmps (at a real 400 watts) pushing one 901 each but that was big time overkill.

I now use a Carver AV-406 (functionally the same as your MM7055) with the 901 EQ in between the AV Receiver's front pre-outs and two 110-watt channels. Other channels on the AV-406 pull subwoofer and surround back duties. My AVR directly powers only the center and surround speakers.

The MM7025 would work for you.

Jul 07, 2011 | Marantz SR7005 Receiver

2 Answers

I have a Boston Acoustics VR-500 Subwoofer with a problem. As soon as anything is plugged into the line level RCA jacks, the subwoofer produces a loud buzz/hum. I have tried connecting it to the subwoofer...


I'm thinking you have an open shield ground on the RCA input side. Connecting speaker inputs possibly restores the ground. Try connecting the high level inputs then disconnect the remote end of the cables (floating the grounds).

Then get out an ohmmeter and find that open circuitor or bad solder joint between RCA ground and real ground in the speaker's amplifier. Or.... if speaker ground kills the hum and you want to use RCA Line Level input to the sub, just connect one minus speaker output on your source amp to one minus on the sub's amp.

Mar 01, 2011 | Audio & Video Receivers

1 Answer

I have a velodyne h6510bg subwoofer, the fuse blew and we replaced it but there is a rattle in the metal cage unit and when you plug in and activate the speaker there is only a humming sound ??


It sounds like the driver itself may have violently blown (the rattle). Is the hum from the speaker (amplfied) without input? Probably something in the amp is gone, too. A hands-on tech would be able to diagnose it for you.

Jan 10, 2011 | Audio & Video Receivers

1 Answer

Subwoofer hum from STR-DH800


That points pretty much to a bad shield on the cable. Have you tried another one? Another thing to try is to rotate the AC power cord on the sub (if it has one). Sorry, too lazy to look it up.

Dec 29, 2009 | Sony STR-DH800

2 Answers

Buzzing/vibration noise from ONYKO TX-SR506 unit


If the unit is under warranty, DO NOT open it up. Bring it in for an exchange or warranty service. Explain that the unit makes noise during use and it will be serviced. This could be as simple as a bad connection in the power supply area and you are hearing oscillations or it could be a defective power transformer. Either case will be covered under warranty so there should be no charge to you.

Keep us posted.

Dan

Feb 17, 2009 | Onkyo TX-SR506 Receiver

2 Answers

Kube 2 subwoofer hum


The Kube Sub-woofer is earthed via its 3 pin plug. The Onkyo and other components I have in my system are not (they are double insulated). During normal operation, a difference in electrical potential can exist between these components in the system. I found that this potential was finding a path to earth via the audio cable and on through the subwoofer's earth. The path was via the earth portion of the audio cable and so gave the hum irrespective of volume levels set either on the Onkyo or the sub.

The fix is to ground the Onkyo to the sub. I used a length of electrical cable between a panel mounting screw on the back of the sub and a screw on the casing at the rear of the Onkyo. Try it out with a piece of cable manually touching screws with the bare ends of the cable until you find ones that give continuity( the hum will go immediately). I then crimped a small fork end electrical fitting onto each end of the cable which can be slid under the slighly loosened screw head and resecured. All I hear now is the fan on the Blu-Ray player!

Jan 31, 2009 | Onkyo TX-SR606 Receiver

1 Answer

2 ohm dvc and monoblock sub amp


Yes. When you run two-two ohm subs to a monoblock amp its on the same channel meaning there ran parallel, and that makes it one ohm and most mono-blocks won't read one ohm. Are you popping fuses in the amp?

Apr 02, 2008 | Audio & Video Receivers

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