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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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5 Suggested Answers

SOURCE: Rockford Fosgate 501bd question

that amp should work fine with those speakers,just make sure that they(speakers)are wired for 2 ohms.at 500-600watts coming from amp, you should be getting 250-300 watts per speaker,just dont crank your gain too high on the amp.

Posted on Sep 01, 2007

OuttaControl
  • 4 Answers

SOURCE: Wiring 2 subwoofers to a mono amp?

The subs can be wired "parralel" or in a "series". it depends on the ohm rating of the speakers and the amp. Most amps can only go down to 2ohms (mono) so it depending on the ohm ratings of the speakers when wired in a series vs parralel that will decide how to wire them. you can always take the safe route and just wire the positives of each to positive on the amp and the negatives to the negatives on the speaker terminals. Do you have the speakers model numbers?

Posted on Dec 22, 2007

  • 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

zzedly
  • 290 Answers

SOURCE: sub hook ups

There's a lot more factors involved than that.

  • Power capability of the subs
  • Type/size of the sub box
  • Allotted space in the vehicle for the sub box
  • Voice coil impedance of the subs versus the capability of the amp
  • Etc.

Posted on Jun 20, 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

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I hv a Memphis 1100 watt mono block n a kicker 12" l7 try to get rid of the flutter or hum at low volume tried just about everything suggestions plzzz


I once got a hum from running the rca and power wires side by side, separated em and problem was solved. Could also be something shorting to the frame, bad ground,cracked insulation on rca wires, the gain might be set to high or maybe the amps dying. It could take over a year for an amp to completely die. But you can always pick up an electronic noise eliminator from radio shack for like ten to twenty bucks

Nov 05, 2014 | Car Audio & Video

1 Answer

I have bose 901 series 2 speakers, marantz 8200 and 2 marantz ma700 monoblock amps how do i hook everything up? Thankd


Do you mean SR-8200? You can't omit the details of a model number if you want a good answer.

Assuming it is...

http://www.retrevo.com/support/Marantz-SR8200-Receivers-manual/id/511ci775/t/2/

Run the 901's with the Active EQ between the receiver Front L and R Pre-Outputs and the mono block amps, one chanel to each.

Pre Out Channel X >>> Bose EQ Amplifer IN, then Bose EQ Amplier OUT >>> Monoblock IN

http://community.klipsch.com/forums/storage/74/1341919/200w%20mono%2005.jpg

I can't find a manual for the MA700. Set them up to a certain volume and then use the speaker setup routines of the SR to match everything up volume-wise. Control will be in the AVR.

Aug 22, 2011 | Bose 901 VI Main / Stereo Speaker

1 Answer

I have a pair of JM lab Electra 905 speakers, running through a DNM amp and power amps. When powered up, the left speaker makes a very loud humming noise. This has happened recently. I haven't changed...


Hello
Switch on your amp, keep its volue down to extreme low, and listen if there is still hum through the left channel or not. If still there is hum, the left side power amplifier section inside the amp;ifier is faulty. If htere is no hum at this state, hum enters thorugh the audio input terminal, and the input wires must be checked for open sheild connection. OK.

Apr 10, 2011 | Jmlab Electra 905 Speaker

1 Answer

I have a yamaha yst sw320 subwoofer connected to a yamaha dsp-a595a amp. I recently disconnected my equipment and when i reconnected it im getting a feedback hum/noise through the sub. I've tried...


Subs don't go to a variety of connections on the amp. Let's stop guessing and stick with the prescribed one.

Register and download the manuals for free at retrevo.com

http://www.retrevo.com/support/Yamaha-YST-SW320-Subwoofers-manual/id/320bh340/t/2/

See page E1 regarding placement and safety.

http://www.retrevo.com/support/Yamaha-DSP-A595-Amps-manual/id/319ag821/t/2/

Page 44 - read about "humming".

If you have hum on the sub, is it there with and/or without the input cable attached?

Disconnect the input(s) and see if it hums in the absence of an audio source. A bad audio cable shield or unwisely-routed audio cables will allow entrance of unwanted signals from external power sources, magnetic fields, even dimmer-controlled track lights. Sometimes, simply reversing the orientation of the ac power plug can eliminate humming.

Mar 02, 2011 | Yamaha YST-SW320 Subwoofer

1 Answer

After a power outage I have a loud hum.


Hi, The Ground Rules Of all the annoyances that can afflict any audio/video home theater or even a simple stereo installation, the notorious "ground loop" may well be the most difficult and persistent one to track down and eliminate. A "ground loop" is caused by the difference in electrical potential at different grounding points in an audio/video system. (All the grounds in an A/V system should ideally be at "0" potential.) A ground loop typically adds a loud low-frequency hum or buzz as soon as you plug in any of various audio or video components, including subwoofers, cable-TV outboard boxes, satellite-TV feeds, TV displays, amplifiers, A/V receivers or turntables. The buzz/hum is a byproduct of the multiple power supply cables and a ground voltage differential within your system and its network of interconnecting cables.

Here are some methods to help you get rid of ground loops. Try these first and don't waste money on a power "conditioner" which, in most cases, won't help. (There is no need to "condition" the AC power for your system. Your receiver or amplifier already has a power supply with its own filters and transformers. No further filtering is normally required.)

If you get your system up and running and hear an audible buzz or hum, the first culprit to look at is either the powered subwoofer or your cable-TV or satellite-box feed at the entry point to your system.

First, the subwoofer: unplug the coaxial cable that connects to your powered subwoofer to see if the ground-loop hum disappears. If it does, it's likely coming in through your cable/satellite TV feed.

Reconnect your subwoofer's coaxial cable from the subwoofer input to your receiver's subwoofer output and disconnect the cable-TV feed (or satellite feed) from your outboard set-top cable box or satellite tuner. Be sure and disconnect the cable before any splitters. Now see if the hum/buzz from your subwoofer stops.

If that eliminates the hum, you can install one of these inexpensive in-line ground isolators from Parts Express or Bass Home. Note that these transformer-based ground isolators will work fine with analog cable-TV feeds, but depending on their design they may interfere with or block reception of HDTV signals via a digital cable or satellite dish feed.

Install the ground isolator between the cable-TV feed and the input of your outboard cable-TV box or satellite tuner (or the TV display's antenna or cable input if you have a set with a built-in TV tuner or a cable-card ready set). In many cases, the ground isolator will "break" the loop and remove the annoying hum or buzz by isolating the TV-cable ground.

If a hum remains with the TV cable completely disconnected from your system, or you don't want to risk degrading reception of HD signals from a cable or satellite system, then you may have to add a ground isolator like this Radio Shack Model 270-054 between the line-level coaxial subwoofer cable from your A/V receiver and the line-level input jack on your powered subwoofer.

In all cases, if your subwoofer has a ground-lift screw like some of Axiom's subwoofers, try first removing the screw (or replacing it) to see if it increases or eliminates the hum. It may or may not make a difference.

If you do not have easy access to the aforementioned ground isolators, here are a few more tips:

Try plugging the subwoofer into a different AC outlet in the room, one that isn't supplying power to your components (A/V receiver, TV, cable box, etc.). That might fix it.

Try reversing the AC plug for your A/V receiver or the powered subwoofer. If it's a 3-wire plug or a polarized plug, which has one prong wider than the other, you won't be able to reverse the plug. For safety, do not use a "cheater plug" to bypass the 3-wire plug.

With the power OFF, reverse the AC plugs one by one of any other components that have a standard 2-prong AC plug that isn't polarized. Each time you reverse a plug, turn on the system with the attached component and your subwoofer and see if the hum disappears. In some cases, reversing one or more plugs will eliminate the hum.

If you have a turntable, try connecting a separate ground wire to a chassis screw on your preamp or receiver and see if the hum disappears. If you already have a turntable ground wire, try removing it from the preamp. One or the other may eliminate the hum.

Finally, here is another solution that worked well for a member of our message boards who decided to discard his ground-loop isolator on his subwoofer: "I took off the ground-loop isolator I'd been using and connected a plain 14-gauge wire to chassis screws on the sub and the receiver then powered everything on. Although hum was still there, it was far lower than before. Next I unscrewed the ground-loop screw on the back of the sub and that took care of the hum completely."

Almost certainly sounds like an earth loop to me, but can be caused by a poorly made transformer or phase shifts on the mains supply. Visit some power conditioner web-sites like Isotek or Isol-8 (or google "earth loop") where there's plenty of advice on how to reduce/eliminate earth loops and other causes of mains-induced hum (transformer problems etc).

Hum on the speakers usually indicates that there is a DC voltage on the speaker line. DC voltage on the output lines would be caused by a shorted output transistor.


Have a nice day...

Feb 16, 2011 | Cambridge Soundworks BassCube 12 Speaker

1 Answer

I just bought a KEF PSW2500 subwoofer and am trying to connect it to a Yamaha v663 receiver. However, I went from a subwoofer pre-out 1 to the right line in on the sub. I don't hear any sounds from the...


HI,go into the yam setup menu and make sure you have the sub turned on and cross over set to about 80hrtz if this suits your speakers,set sub level to about -5 on amp and say half way on the sub,this should work if not pull out sub cable at amp and touch the end,you should get a hum,if not you may have no power,faulty cable or sub.
PS>make sure you are pluged into the sub PRE OUT and NOT the six channel in.
Hope this helps.
CABLE GUY.

Apr 19, 2009 | KEF Audio PSW 2500 Subwoofer

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

3 Answers

Miller & Kreisel Subwoofer 60Hz hum


This is a common problem.  The potentiometer is damaged and needs to be replaced.  Potentiometer is a fancy name for volume knob.  It's a $5.00 fix if you know what you're doing.

Dec 01, 2007 | Audio Players & Recorders

1 Answer

Loud hum on subwoofer.


try another speaker on that channel if you get no sound or it hums then it is time to take your set to a tech your audio out put on that side is damage along with some caps.good luck.

Mar 30, 2007 | Polk Audio RT1000I Speaker

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