Question about Celestion S8 Subwoofer

7 Answers

Celestion S8 Subwoofer

Hi folks, My S8 has started humming all the time, with or without the phono lead in, and in all on/off/auto positions. It's been a pretty good sub so far so I'd rather try and fix it than dump it! Could it be a coupling cap or a resistor gone high in the amp? Any help much appreciated! Oberon

Posted by on

  • 1 more comment 
  • Anonymous Jan 02, 2008

    i have the same problem with mine it seems to be the blue relay chattering , voltages and cappies seem ok, the reason for the chatter is unknown anyone out there got a circuit diagram.

  • Anonymous Aug 08, 2008

    I have an S8 with the chattering relay issue and we are not alone - looking about a few forums it is a widespread problem.

    I got hold of the schematice for a kef psw2000 which is broadly similar and after browsing the diagram and a few forums I plan to replace the main smoothing caps and also c52, which sits after the relat and smooths the full supply voltage, it has a hard life and I suspect the 63v part that is fitted has not lasted.

  • GlennyG Sep 08, 2008

    Same issue with the KEF PSW2000. More info & circuit diagram/service manual here:



7 Answers


re: It's a problem in the grounding of the unit all you need is receptacle adapter that takes away the ground plug on the power cable.

If it is an 'earth' ground loop problem then this would likely solve the issue but it's unsafe as the S8 needs its earth connection to be safe in case of electrical fault. It's not 'double insulated' construction.

And if it makes the noise / hum without being connected to any other piece of kit then it's not an 'earthing' problem anyway.

I have a faulty S8 which just makes either no sound or a big hum just on its own.

Posted on Nov 01, 2008

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

The relay chatter is because its getting AC from the board. I took the relay off the board and tested it with 24VDC it works fine - checking with a multimeter it seems the relay is getting about 20vDC and at the same time 8V AC ! Normally my multimeter wont read AC if its DC and vice versa - very strange! But the question is what is causing the circuit to get AC?

Posted on Mar 07, 2008

  • Dan Lodge
    Dan Lodge Jan 04, 2018

    I have the same issue. How did you fix it?

  • Dan Lodge
    Dan Lodge Jan 04, 2018

    I have the same issue. How did you fix it?



It's a problem in the grounding of the unit all you need is receptacle adapter that takes away the ground plug on the power cable.

Posted on Feb 24, 2008

I too found my subwoofer humming after about 3 years... weird thing is i found the solution to my problem... i turned on my sub, it hummed, i disconect the cable from my tv, IT STOPS!!! i am going to radioshack tomarrow to pick up a device that connects my cable to my tv to stop the interference

Posted on Nov 13, 2007

If the sound source is on a different circuit or plug it produces some kind of a loop (dont know the technical name) Go to radio shack and get a ground loop disrupter that goes on the audio cables right before the speaker and it eliminates that hum.

Posted on Oct 05, 2007

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 1 Answer

When you say check the caps what do you mean? I also have a Celestion S8 Sub that is about 3 years old and has just started doing this exact same thing. Celestion say they'll fix it for about £50. Could you be a bit more specific for those of us that don't know much about electronics :o)

Posted on Nov 02, 2006

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    An expert who has written 20 answers of more than 400 characters.


    An expert who has answered 20 questions.

  • Expert
  • 72 Answers

I would check the electroltyc caps in the power supply They general are in the first part of the power supply and there will be two of them . What they do is filter out transformer hum and help stabalize the circuit. I am not saying this is absolutely the problem but the capcitors are relatively inexpensive, Easy to change. And have a habit of going bad after a couple of years in use.

Posted on Sep 03, 2006

1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

How do I set up a Celestion S10 Subwoofer...

Voltage is relevant to where you live in the world. America it's 110. Europe mostly 220.
What you're asking is a very deep and complicated question.
I'm attaching a link with some articles.
What I suggest is that you find an upper end audio store and ask a 20 audio head to set up your system for you. Subwoofer Setup and Calibration for Best Bass

Apr 12, 2014 | Celestion S10 Subwoofer

1 Answer

Loud hum on mirage omni s8

need to replace the amp assembly...common problem on this model.

Dec 04, 2013 | Mirage OMNI S8 Speaker

1 Answer

S8 makes a very loud vibrating buzzing noise with only the power lead plugged in

Check for ground loops. Also shut off any CFL or LED lamps inthe vicinity.

You may also have an intermittent connection on the input.

There is a lesser chance that there is an internal failure of a capacitor on the amp power supply, but it is a possibility to look at if all the wiring is in place and soundly connected. The S8 has a high gain amp. It will pick up interference from CCFL or LED ballasting supplies it will also be able to pick up other switch mode power supplies. in vicinity of the input cable.

Jan 07, 2012 | Celestion S8 Subwoofer

2 Answers

Mirage s8 subwoofer is emitting a constant hum

that is just the radio from the input,its normal

Jun 19, 2010 | Mirage Prestige S8 Subwoofer Speaker

2 Answers

Humming sound in subwoofer after it's been playing for a while

It sounds like you are describing an earth loop problem. I won't go into detail in this post, but try an isolation test first. disconnect everything from the reciever except the sub and try connecting say a BATTERY powered mp3 player or cd player to minimise connections to the electrical mains earth. you could also isolate things by taking your sub to a friend's house and trying it on their system.
If it is an earth loop use a process of elimination to find out which two pieces of equipment causes the earth loop. then apply filtering.
you can buy earth loop isolation transformers for about AU$26 and I've used one on my sub myself. Theyhave RCA (phono)plugs on each end and they connect inline with the signal cable to the sub amp.

as for the thumping sound it might be the speaker protection circuitry cutting off the amp to protect the subwoofer speaker from damaged. This might be triggered if the earth loop sound is causing the sub amp to overload and clip.

Failing this there might be a dried out overheated electro capacitor in the amp circuit causing the hum. Hav a chat to your local electronics person, who should be able to spot it!
Hope this puts you on the right track
Happy Hunting!

Jan 07, 2010 | Sunfire Audio Players & Recorders

1 Answer

Auto/on switch

unplug it when your not in use,,,

May 12, 2009 | Celestion S10 Subwoofer

1 Answer

Subwoofer hum


Based on your description, the internal power supply of the subwoofer amplifier would be suspect. Often it would be a blistered or leaking filter capacitor. It is a relatively easy/inexpensive repair.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information. Good luck and kind regards. Thank you for using FixYa.

Nov 09, 2008 | Jensen JHT525 System

Not finding what you are looking for?
Celestion S8 Subwoofer Logo

3,741 people viewed this question

Ask a Question

Usually answered in minutes!

Top Celestion Audio Players & Recorders Experts


Level 3 Expert

5601 Answers

michael wilkins

Level 1 Expert

2 Answers

Richard Lindsey ...

Level 2 Expert

211 Answers

Are you a Celestion Audio Player and Recorder Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides