I have a Onkyo CD 7030 player thats about 11 months old.
Until recently it's been whisper quiet both in operation and on idle however a few days ago upon turning on a noticed a very faint buzz when i powered up.
The buzz is not obtrusive theres no ' vibration ' or chassis tingle but it's definitely not something thats always been there .
Sound quality etc is normal but my concern is that this ' new ' noise is the beginning of a possible issue that will get worse?
Any advice on whats caused this would be appreciated as with less than one months warranty left i need to make a decision on further investigation.
Just to add nothing in the system has been changed since installed, same cables , mains outlet etc.
Until recently it's been whisper quiet both in operation and on idle however a few days ago upon turning on a noticed a very faint buzz when i powered up.
The buzz is not obtrusive theres no ' vibration ' or chassis tingle but it's definitely not something thats always been there .
Sound quality etc is normal but my concern is that this ' new ' noise is the beginning of a possible issue that will get worse?
Any advice on whats caused this would be appreciated as with less than one months warranty left i need to make a decision on further investigation.
Just to add nothing in the system has been changed since installed, same cables , mains outlet etc.
Thats a good question as the player works fine and the noise is so faint , they would probably say nothing wrong with it and label me as obsessive 😀
Measure your mains voltage and see if its on the high side. If it is then the transformer could be saturating and causing the mechanical buzz you hear.
I 'm a speaker man and have very little knowledge of electronics beyond it hurts if you get it wrong Mooly , hence no gear to measure my mains supply.
I haven't noticed any differences with any other equipment though , no new hums or buzzing etc.
I assume that Boky means the plates are coming apart with age and the subsequent vibration is whats making the noise ?
I 'm considering using this ' issue ' as an excuse to upgrade though 😀
I haven't noticed any differences with any other equipment though , no new hums or buzzing etc.
I assume that Boky means the plates are coming apart with age and the subsequent vibration is whats making the noise ?
I 'm considering using this ' issue ' as an excuse to upgrade though 😀
If you see an opportunity.....go for it...it was only £200(?) doubt they'll offer to repair it. Funny, I've noticed on this forum how there are speaker people and everything else people, I have a theory it's about distortion, everything else people like to talk about it because it's a technical challenge, speaker people laugh because they know they're wasting their time. I'm more of a tart!
I concur with Mooly. I once had transformer buzzing problems with a toroidal main transformer for a power amp which would disappear after lowering the A.C. input by a few volts RMS (via Variac), and then reappear when raised by the same few volts.
D.C. offset on the power mains is another possibility which can also cause core saturation, although such offset tends to manifest intermittently, depnding on the reactive loads sharing your power mains feed.
I would try it on another outlet, or at a friend's home if possible to rule out any interference possibility.
Thanks for the replies everyone , i think i've found the cause of the problem.
I spent some time yesterday listening to music and when i had finished i , as always ,
first turned the amp off via the manual switch on the front and as i did the buzz from the cd player decreased enormously .
As mentioned previously the initial noise although not loud could be heard from about 2 foot away .
With the amp off the buzz was barely noticable and i would go so far as saying well within manufacturing tolerances .
Next i turned the cd off and switched the amp back on expecting to hear the noise and there was nothing the amp was completely silent.
Further investigation concluded ...
Amp on ... silence , no buzz no noise from speakers .
Amp off ... Cdp on , very faint buzz from player.
Amp and Cdp both on .... loud buzz from Cdp.
i 've had ground loops before but this didn't sound like one and after almost a year with no changes to the environment or system seemed odd that one would suddenly appear?
Anyway i started moving mains cables around but the buzz didn't change then i remembered that a while back i had purchased a new RCA interconnect whilst online shopping when drunk from a company i normally accuse of selling snake oil.
As i had the system apart i thought i may as well try it and installing it completely cured the buzzing .
So i assume that the problem was caused by a problem with the IC i had been using although i don't understand how a cable can suddenly ' break ' so an explanation from someone who understands these things more than me would be appreciated.
Problem i have now is i looked around the net yesterday thinking i may have to buy a new cdp and found a Myryad Z210 in a clearance at a third of R.R.P. brand new , 2 in stock ......temptation 😀
I spent some time yesterday listening to music and when i had finished i , as always ,
first turned the amp off via the manual switch on the front and as i did the buzz from the cd player decreased enormously .
As mentioned previously the initial noise although not loud could be heard from about 2 foot away .
With the amp off the buzz was barely noticable and i would go so far as saying well within manufacturing tolerances .
Next i turned the cd off and switched the amp back on expecting to hear the noise and there was nothing the amp was completely silent.
Further investigation concluded ...
Amp on ... silence , no buzz no noise from speakers .
Amp off ... Cdp on , very faint buzz from player.
Amp and Cdp both on .... loud buzz from Cdp.
i 've had ground loops before but this didn't sound like one and after almost a year with no changes to the environment or system seemed odd that one would suddenly appear?
Anyway i started moving mains cables around but the buzz didn't change then i remembered that a while back i had purchased a new RCA interconnect whilst online shopping when drunk from a company i normally accuse of selling snake oil.
As i had the system apart i thought i may as well try it and installing it completely cured the buzzing .
So i assume that the problem was caused by a problem with the IC i had been using although i don't understand how a cable can suddenly ' break ' so an explanation from someone who understands these things more than me would be appreciated.
Problem i have now is i looked around the net yesterday thinking i may have to buy a new cdp and found a Myryad Z210 in a clearance at a third of R.R.P. brand new , 2 in stock ......temptation 😀
That should be ok. The player is class 2 insulated so ground loop wouldn't be it. Have you tried the old cable again, is the new one thicker?
I'm pretty sure it wasn't a ground loop was more of a buzz than a hum if that makes sense .
I binned the old cable which was a cheap Maplin ' PRO ' gold , their top of the range 🙂 and the new one is .. cough... Audioquests budget Tower ( solid core ) .
None of what happened makes sense to me but the cable cured it , i hope.
I binned the old cable which was a cheap Maplin ' PRO ' gold , their top of the range 🙂 and the new one is .. cough... Audioquests budget Tower ( solid core ) .
None of what happened makes sense to me but the cable cured it , i hope.
Mechanical buzz from the CDP transformer should not change as cables are swapped.
Switching the amp off and hearing the mechanical buzz from the CDP decrease, or conversely amp on and buzz increase makes a lot of sense if you figure the mains supply impedance into the equation.
The amp will draw large 'spikes' each half cycle as it replenishes the reservoir caps. If the impedance of the supply is high then that spike will reflect onto the mains and cause it to become less sinusoidal which in turn will upset the CDP and manifest as mechanical buzz.
There is some logic there.
The next basic tests would be to see how well the mains supply holds up as you draw a significant load (such as 2 or 3 kWh heater) connected to the same outlet.
And again, all these issues will seem better/worse depending on the mains voltage at the time and also its purity.
Switching the amp off and hearing the mechanical buzz from the CDP decrease, or conversely amp on and buzz increase makes a lot of sense if you figure the mains supply impedance into the equation.
The amp will draw large 'spikes' each half cycle as it replenishes the reservoir caps. If the impedance of the supply is high then that spike will reflect onto the mains and cause it to become less sinusoidal which in turn will upset the CDP and manifest as mechanical buzz.
There is some logic there.
The next basic tests would be to see how well the mains supply holds up as you draw a significant load (such as 2 or 3 kWh heater) connected to the same outlet.
And again, all these issues will seem better/worse depending on the mains voltage at the time and also its purity.
Thanks Mooly that makes sense to me now ^ , maybe just coincidence swopping cables helped then , systems been playing all day no issues .
Possible work being done nearby to main supply could have caused peaks ? or would it just be an internal ' house ' issue?
House was built 60's ish i think and landlord had a RCD system fitted last year which trips if i so much as look at a lightbulb 😀
No issues with noise or distortion when the freezer etc kicks in though .
As i said though i know little about electrics , can you explain what tools needed and how i measure the mains voltage/impedance please?
Possible work being done nearby to main supply could have caused peaks ? or would it just be an internal ' house ' issue?
House was built 60's ish i think and landlord had a RCD system fitted last year which trips if i so much as look at a lightbulb 😀
No issues with noise or distortion when the freezer etc kicks in though .
As i said though i know little about electrics , can you explain what tools needed and how i measure the mains voltage/impedance please?
Incidentally the guy that fitted the RCD mumbled something about the earth or lack of potentially causing all the pipework in the house becoming live if there was a fault and ran a new earth from the main box to a pipe under my kitchen sink ( i think )
I wouldn't like to second guess your mains installation but simply measuring the mains voltage can be revealing, and not just the absolute value but also how it may vary at different times of the day and also how well it holds up under load.
That said, if you unsure how to do this or have no experience then dabbling with the mains might not be advisable because to measure the mains you need to connect a suitable meter (a multimeter or DVM) across live and neutral whilst having the meter switched to suitable AC voltage range. From that point you could see how the supply held up under load, for example switching an electric shower or cooker on and seeing how much the voltage falls.
If it fell a lot then that implies the supply has a highish impedance and can not deliver the required current as well as it might... and that also means that something plugged into the supply and that has a varying load is able to modulate or alter that supply.
That said, if you unsure how to do this or have no experience then dabbling with the mains might not be advisable because to measure the mains you need to connect a suitable meter (a multimeter or DVM) across live and neutral whilst having the meter switched to suitable AC voltage range. From that point you could see how the supply held up under load, for example switching an electric shower or cooker on and seeing how much the voltage falls.
If it fell a lot then that implies the supply has a highish impedance and can not deliver the required current as well as it might... and that also means that something plugged into the supply and that has a varying load is able to modulate or alter that supply.
I am presuming he is hearing the buzz before any music is being played. Would the amp still draw large spikes under this condition?
Yes, the quiescent current of the amp is quite sufficient to do that, particularly if it uses large low impedance reservoir caps and has a big transformer.
Its just one 'possible' out of many reasons. There are a lot of unknowns.
This shows the voltage on the rails of a typical amplifier and also the AC voltage feeding each half of the bridge rectifier. There is 0.4 ohms impedance added to each AC supply to highlight the effect which shows as the sine starting to 'flat top' a little.
Its just one 'possible' out of many reasons. There are a lot of unknowns.
This shows the voltage on the rails of a typical amplifier and also the AC voltage feeding each half of the bridge rectifier. There is 0.4 ohms impedance added to each AC supply to highlight the effect which shows as the sine starting to 'flat top' a little.
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