REL Strata 5 Pulsing

Discussion in 'Subwoofers' started by Ygolonac, Jan 18, 2008.

  1. Ygolonac

    Ygolonac
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    Hi,

    I have a REL Strata 5 which has been great, but now I have an issue.

    Searching the forums I've found posts on humming and ground loops etc but I'm not sure they cover my exact problem.

    When the sub is on I generally get a pulsing hum sound from it, at approximately 1 hum per second. If I change the phase to 180 from 0 it will change to a strange strangled constant hum.

    Here's a list of stuff I've found/tried so far:
    • Disconnecting the LFE cable form the sub - no change.
    • Disconnecting the High Level input - no change.
    • So at this point I've got a stand alone sub with a humming issue!
    • Rebooting the sub - hum will go away for a while and then randomly come back on.
    • Changing LFE and HL levels/cross-overs etc has very little effect on the problem.
    • Turning off my Amp (STR-DA5200ES) and the hum stops - even though the amp and the sub aren't directly connected anymore.
    • Connecting Amp to same electrical socket as sub - still hums.
    • Putting a mains rectifier (cheap maplins job though) on the mains socket - still hums.
    • Putting the Amp on a completely different mains socket - still hums.
    • Connecting the ground of the Neutrik (or whatever it's called) connector to the ground on the amp instead of the negative speaker connection - still hums.

    The sub appears to work perfectly well other than the hum - bass reproduction in movies etc is fine.
    The problem has been suspiciously coincident with the purchase of the amp.

    So looking for any good suggestions on how to fix it, or in the worst case what a good replacement sub is that should be of at least the same quality.

    Cheers in advance.
     
  2. avmoron

    avmoron
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    From what you describe - the Sub is pulsing even when not connected to the amplifier I would think that this is due to EMF ( electromagnetic field) from the amplifier which is affecting the subs electronics. Seperate the sub from the amp as a test power up the sub in a different room and see if it still pulses. If it doesnt then it is probably due to EMF. If my theory is correct you will need to shield the sub from the amplifier, try placing a metal tray in the way.
     
  3. Ygolonac

    Ygolonac
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    The sub is about 1.5 metres away from the amp so I'd be surprised if it was EMF there.

    However there are all the speaker cables and the front right speaker right next to it so I'll experiment with moving them about or briefly disconnecting them. I can quite easily believe that it's caused by the speakers as I also upgraded those recently and now they are closer to the sub than they were.

    Good thinking and thanks, I'll report back on my findings :thumbsup:
     
  4. iSix

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    Could also be noise on the mains generated by the amp. Can you try the sub on a different ring?
     
  5. Resonance

    Resonance
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    Do any of the other controls on the sub affect the hum?
     
  6. Ygolonac

    Ygolonac
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    Moving the sub further away from the speakers has improved the hum in one way:
    When the pulsing hum starts it's just the same as it used to be, however it starts very infrequently now.

    Haven't tried moving it to another room yet, its a bit chunky to be moving around so I'll probably do it next weekend.

    The other controls have little effect on the existence of the hum, but they still change the sound of it i.e. increased slam depth makes it more punchy.

    I'll experiment again next weekend and see if I can come to any conclusions.

    Thanks to all for the help :thumbsup:
     
  7. Ygolonac

    Ygolonac
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    Bah...

    Unless it's a mains ground loop issue then the thing is broken.

    Totally disconnected from the amp, no LF channel, no Neutrik, away from speakers, and it still can get into the pulsing hum mode.

    The only thing left to try is to isolate the sub onto another mains ring - which isn't much help considering where it needs to be placed.

    I'll experiment more at the weekend but I think I'll be looking for suggestions for a replacement sub of equal caliber :mad:
     
  8. Dreamer 29

    Dreamer 29
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    Hi, I once had a Kef sub which had a similar problem to your sub. So I had it repaired for £50 and they told me the power capacitors had failed. Hope this is of use to you.
     

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