Hi,
My first time on here so please be gentle.
I have recently upgraded my hi-fi using carefully selected second-hand components via Ebay!
I have purchased an Arcam Alpha 8 integrated amp and run it with a Cambridge Audio CD player and KEF IQ5SE speakers.
Upon rigging up the amp and powering up, I noticed a deep buzz/humming coming from both speakers, only when no music being played. The sound of CDs seems unaffected. This sound is audible even if the CD player is switched off and doesn't change/get louder when the volume is adjusted.
The buzz/humming is only audible when the 'Direct' button ISN'T pressed. I have spoken to Arcam who don't think it's a big issue as I should be running it with the 'Direct' button pressed. With the button pressed it sounds great. It's just a little annoyance and something that is bugging me at the back of my mind. The amp sounds fantastic and makes the speakers sing!
Arcam techies also said that the speakers require power and that is what I'm hearing. They charge £198 to assess and rectify any faults but I think that's a bit strong for something that may not even be an issue! I only paid £125 for the amp and it is in 'as new' condition. Not a mark on it.
I am particularly fussy but just wanted a viewpoint from others who may know what this is or, indeed, if it's a problem. I'm not proficient with electronics but, if there is something that could be cleaned or something obvious to look for inside, then I could take a look.
Any thoughts appreciated.
My first time on here so please be gentle.
I have recently upgraded my hi-fi using carefully selected second-hand components via Ebay!
I have purchased an Arcam Alpha 8 integrated amp and run it with a Cambridge Audio CD player and KEF IQ5SE speakers.
Upon rigging up the amp and powering up, I noticed a deep buzz/humming coming from both speakers, only when no music being played. The sound of CDs seems unaffected. This sound is audible even if the CD player is switched off and doesn't change/get louder when the volume is adjusted.
The buzz/humming is only audible when the 'Direct' button ISN'T pressed. I have spoken to Arcam who don't think it's a big issue as I should be running it with the 'Direct' button pressed. With the button pressed it sounds great. It's just a little annoyance and something that is bugging me at the back of my mind. The amp sounds fantastic and makes the speakers sing!
Arcam techies also said that the speakers require power and that is what I'm hearing. They charge £198 to assess and rectify any faults but I think that's a bit strong for something that may not even be an issue! I only paid £125 for the amp and it is in 'as new' condition. Not a mark on it.
I am particularly fussy but just wanted a viewpoint from others who may know what this is or, indeed, if it's a problem. I'm not proficient with electronics but, if there is something that could be cleaned or something obvious to look for inside, then I could take a look.
Any thoughts appreciated.
Welcome to diyAudio 🙂
So... the direct button I assume defeats the tone controls and just links them out of the circuit path. If the tone controls are centred then there should be no audible difference as the direct button is pressed, however...
These kind of issues are hard to diagnose. If you have just the amp and speakers connected (nothing else plugged into it) then you should hear no noticeable hum under any conditions, direct switch in or out. Ideally, shorting plugs should be fitted to the input selected (CD) for this test, but even without there should be no loud hum. Try it !
The amp should not be stood on or have stood upon it any other equipment as that can radiate a magnetic field from its transformer into the circuitry... result hum. If in doubt just move the amp to its own free space and retest.
If its a 'real' fault then thoughts turn to whether there is physical damage such as cracked print around any 'sticky out bits' such as the switch.
As to Arcams comment on the speakers requiring power and that is what you are hearing... well all I would say to that is that the speakers only produce sound when a voltage is applied to them and if that voltage is 'hum voltage' then its coming from the amp. If they are/were implying the speakers are inefficient and need the volume turning up a lot (and so that is why you hear the hum) then they are admitting their amp has a general problem (which I doubt).
So... the direct button I assume defeats the tone controls and just links them out of the circuit path. If the tone controls are centred then there should be no audible difference as the direct button is pressed, however...
These kind of issues are hard to diagnose. If you have just the amp and speakers connected (nothing else plugged into it) then you should hear no noticeable hum under any conditions, direct switch in or out. Ideally, shorting plugs should be fitted to the input selected (CD) for this test, but even without there should be no loud hum. Try it !
The amp should not be stood on or have stood upon it any other equipment as that can radiate a magnetic field from its transformer into the circuitry... result hum. If in doubt just move the amp to its own free space and retest.
If its a 'real' fault then thoughts turn to whether there is physical damage such as cracked print around any 'sticky out bits' such as the switch.
As to Arcams comment on the speakers requiring power and that is what you are hearing... well all I would say to that is that the speakers only produce sound when a voltage is applied to them and if that voltage is 'hum voltage' then its coming from the amp. If they are/were implying the speakers are inefficient and need the volume turning up a lot (and so that is why you hear the hum) then they are admitting their amp has a general problem (which I doubt).
Sounds like some capacitors in the preamp power supply section have seen better days and are begging to be replaced, or maybe a regulator has developed a problem.
Just looked at the specs... a 50 wpc amp dating from 1998 that weighs a whopping 4.5 kg. You can get a new (and possibly better) amp like that for £198... say, a Yamaha A-S301.
Just looked at the specs... a 50 wpc amp dating from 1998 that weighs a whopping 4.5 kg. You can get a new (and possibly better) amp like that for £198... say, a Yamaha A-S301.
The direct button overrides the tone and balance controls so, in essence, the amp just becomes an amp and bypasses the other circuits.
If memory serves me correctly (am at work so can't test immediately) there is a tiny 'pop' when turning direct on/off. The low humming noise is only audible with direct turned off. It's heard through both speakers and the volume doesn't change it. Strange.
The amp is certainly powerful enough to drive the KEF speakers.
Wonder if it's worth getting an electronics engineer to take a look at it for anything obvious. Just a little annoyance on an otherwise perfect amp.
The seller has offered to pay for any fix (as long as it doesn't amount to the value of the sale of the amp) which I thought was fair enough. Do I investigate further, take a look myself or leave well alone and stop being so fussy!
Not sure if there's any other test I can do - bearing in mind I am in no way techy when it comes to electronics or diagnostics!
If memory serves me correctly (am at work so can't test immediately) there is a tiny 'pop' when turning direct on/off. The low humming noise is only audible with direct turned off. It's heard through both speakers and the volume doesn't change it. Strange.
The amp is certainly powerful enough to drive the KEF speakers.
Wonder if it's worth getting an electronics engineer to take a look at it for anything obvious. Just a little annoyance on an otherwise perfect amp.
The seller has offered to pay for any fix (as long as it doesn't amount to the value of the sale of the amp) which I thought was fair enough. Do I investigate further, take a look myself or leave well alone and stop being so fussy!
Not sure if there's any other test I can do - bearing in mind I am in no way techy when it comes to electronics or diagnostics!
I would advise going through the basic tests first to see if there really is a problem.
1/ With just the amp and the speakers connected and Direct set to off, does it hum ?
(you must have NO other leads connected to the amp)
2/ Now turn 'Direct' on. There should be no change in any hum level. Any hum present should be so slight that you can only hear it when your ear is up against the speaker.
See if it passes that test first.
1/ With just the amp and the speakers connected and Direct set to off, does it hum ?
(you must have NO other leads connected to the amp)
2/ Now turn 'Direct' on. There should be no change in any hum level. Any hum present should be so slight that you can only hear it when your ear is up against the speaker.
See if it passes that test first.
Ah OK - it did it with Direct 'off' with the CD player off but still connected. Will disconnect from the amp and try this when I get home. Really hope it's nothing serious as it sounds lovely and only seems to be an issue when direct is switched off. Just one of those little annoyances.
If it still does it after doing this - what next!?
If it still does it after doing this - what next!?
Yes, it must be tested initially with all other leads removed. If it hums in this condition then its really case of seeing if it meets its published spec for hum/noise which would need special test equipment. Looked at empirically though, hum should not be noticeable to a user at more than a few inches from the speaker in this test set up.
See what you find with this first.
See what you find with this first.
Hmmm It's broken ? Reads as that way
Mine does Not do that. Nor does it Pop in any audible way when cycling the Direct Button.
That said; Direct makes for V small (if Any) audible difference.
It's in perfect condition, as it was a seriously dissapointing sounding purchase (brand new) has had Very few hours usage
Stereopile Rated it as Wonderous and a cut above all others. Complete Nonsense IMO
Amazingly..for the 'price' of a factory repair one could buy a ...far... better performing amp unit.
Merely MY 2 cents 🙂
Mine does Not do that. Nor does it Pop in any audible way when cycling the Direct Button.
That said; Direct makes for V small (if Any) audible difference.
It's in perfect condition, as it was a seriously dissapointing sounding purchase (brand new) has had Very few hours usage
Stereopile Rated it as Wonderous and a cut above all others. Complete Nonsense IMO
Amazingly..for the 'price' of a factory repair one could buy a ...far... better performing amp unit.
Merely MY 2 cents 🙂
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OK, good news, possibly!
I disconnected the phono leads from the back of the amp and there is no buzz at all coming via the speakers. It only makes it when reconnected via CD or Aux in the back of the amp. Not very loud at all but it's there with direct 'off' as I say.
The CD/DVD player is an old, cheap Cambridge Audio unit. This now suggests that the fault lies with the CD/DVD player. Would I be correct with that assumption?
I had planned on replacing it with an Arcam DVD/CD player anyway so perhaps this is the next step for 100% peace of mind?
Maybe, maybe not 😉
Leave the player coupled to the amp but this time unplug the player mains connection.
Has the hum gone ?
OK, have tried this with phono leads connected but CD/DVD player completely unplugged. The faint buzz is there with direct button off.
Is there another way to connect the player. Could I try video for the input?
The phono leads are old too.
Is the hum still as loud though ?
What I was trying to establish is whether the problem is caused by a 'ground loop' where two pieces of equipment are both connected to mains ground via their mains plugs. This can cause a small circulating current to develop that manifests as a hum, pure and deep like you first mentioned.
You can use any of the line level inputs such as CD, Video, Tuner (or whatever they are marked as). I think you will find they are all similar.
At this point it would be worth trying a different player if possible.
What is a bit strange is that the amp appears silent when nothing is connected (and presumably with the direct switch in either position) and yet when connected to a non powered player it seems that the switch position then does have an effect. Have I got that right ? If so then that part of it all 'does not compute'.
What I was trying to establish is whether the problem is caused by a 'ground loop' where two pieces of equipment are both connected to mains ground via their mains plugs. This can cause a small circulating current to develop that manifests as a hum, pure and deep like you first mentioned.
You can use any of the line level inputs such as CD, Video, Tuner (or whatever they are marked as). I think you will find they are all similar.
At this point it would be worth trying a different player if possible.
What is a bit strange is that the amp appears silent when nothing is connected (and presumably with the direct switch in either position) and yet when connected to a non powered player it seems that the switch position then does have an effect. Have I got that right ? If so then that part of it all 'does not compute'.
Yes, as you put it in the last para. No buzz/hum at all when leads in the back of the amp but disconnected from CD player. However, noise appears when leads connected to CD player, even when unplugged from the mains (unless it is retaining some power somewhere!?). Again, the noise only appears on direct off. A very faint, deep buzz. The balance does affect it from left to right slightly. Odd, isn't it!? Hoping the CD player isn't as compatible as it should be!
Meant to add that the buzz doesn't change in loudness with leads connected but unplugged or not. If you turn the volume right up it does get a tiny bit louder. All very marginal but it's there!
Just one more thing we can try in the hope to pin this down. With the leads connected to the amp not connected to the player you say it is quiet. In my first reply I mentioned that ideally we should use shorting plugs... so lets do a quick and dirty test.
Make sure the amp is off initially and that the phono leads are connected. Now get some silver foil (cooking foil etc) and tightly shove some into the open end of the leads (shove it right into the plug) so that it shorts the centre pin to the outer part. Do that on both left and right plugs.
Has that brought the hum back or not ?
Now still keeping the amp on, and with the volume turned down initially, short the left and right leads together by just holding the plugs tightly together (still with all the foil shorting each plug out) and see if its still quiet.
If it has then its most likely a problem with the amp (possibly even a design issue with internal grounding and layout) or less likely a problem with the lead picking up some stray radiated field. Retesting with another lead is the only way to prove that.
Make sure the amp is off initially and that the phono leads are connected. Now get some silver foil (cooking foil etc) and tightly shove some into the open end of the leads (shove it right into the plug) so that it shorts the centre pin to the outer part. Do that on both left and right plugs.
Has that brought the hum back or not ?
Now still keeping the amp on, and with the volume turned down initially, short the left and right leads together by just holding the plugs tightly together (still with all the foil shorting each plug out) and see if its still quiet.
If it has then its most likely a problem with the amp (possibly even a design issue with internal grounding and layout) or less likely a problem with the lead picking up some stray radiated field. Retesting with another lead is the only way to prove that.
OK - I'll try this out later on tonight when I get home. Appreciate all your help on this!
I meant to add, although the Ebay link below is not my CA DVD/CD player, it looks exactly the same. If you look at the images, there is one of the back panel. Without being in danger of sounding really inept, I have the phono leads coming out of the 'Front' L/R sockets. Would this be correct or could I try something else that may work?
Cambridge Audio DVD53, Stereo CD/DVD Player with Original Remote Control, Audio | eBay
Cambridge Audio DVD53, Stereo CD/DVD Player with Original Remote Control, Audio | eBay
Bit hard to see in the picture, but does one set say '2ch out' ? I would think that would be the one to use.
Maplin 😱
Try here instead. Search for ground loop isolator
B070. - UNBRANDED - GROUND LOOP ISOLATOR | CPC UK
See what the further tests show first before considering anything like this though.
Maplin 😱
Try here instead. Search for ground loop isolator
B070. - UNBRANDED - GROUND LOOP ISOLATOR | CPC UK
See what the further tests show first before considering anything like this though.
Yes, it says '2CH OUT'. I have been using 'FRONT' which is the second set of sockets in from the left. Could that create issues?
I agree re Maplin and got an isolator via Ebay very much like the one in the link you've provided.
I agree re Maplin and got an isolator via Ebay very much like the one in the link you've provided.
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