Buzz from Tweeters.

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Autor
Beitrag
Voodoo_CHild
Stammgast
#1 erstellt: 01. Okt 2007, 06:36
Need some help guys...

Each time I increase the volume level by a notch, I hear a buzz from the Tweeters (similar to a crackling noise).

This happens when the volume knob on my amp is operated clockwise to increase the sound level.

Edit:
I did observe the same thing happen when the volume is decreased in step by step manner, although not as prominent as earlier, but is definitely there.

I could clearly make out the buzz when I rotated the volume knob up/down during silent passages or fewer instruments are being played on a cd recording.

Only when the volume level is kept constant, no buzz is heard.

Things I've tried are:

I got a friend's nad c352 and connected it to my speakers, the same happened...in fact the noise was more pronounced compared to my nad c325bee.

Later I plugged my headphones to the headphone socket of both the amps and checked. I could hear the buzz on both occasions when volume was increased.

Source is a philips dvdp, havent tried any other.

What could be wrong?


[Beitrag von Voodoo_CHild am 01. Okt 2007, 12:10 bearbeitet]
Kamal
Stammgast
#2 erstellt: 01. Okt 2007, 13:01
Worn out/dusty pot?
Try twiddling the Vol Control to & Fro quickly 15-20 times
while the amp is off & then see.
Savyasaachi
Inventar
#3 erstellt: 01. Okt 2007, 16:31
This is most definitely a grounding problem.
Voodoo_CHild
Stammgast
#4 erstellt: 01. Okt 2007, 17:37

Kamal schrieb:
Worn out/dusty pot?
Try twiddling the Vol Control to & Fro quickly 15-20 times
while the amp is off & then see.


Tried it Sir..didnt quite help...removed and reconnected all the cables as well. In the process, did a bit of cleaning on the connectors & all..
Voodoo_CHild
Stammgast
#5 erstellt: 01. Okt 2007, 18:23

Savyasaachi schrieb:
This is most definitely a grounding problem.


Saachi,

Assuming its the ground...any leads on what can be done, how/what to check..etc?

Few more(!)things I've tried so far:

Amp is directly plugged to the wall socket and the dvdp is connected thru a v-guard stabilizer to a different connector on the same wall socket. I removed the v-guard and plugged the dvdp directly to the wall...and I get a mild shock if I touch the top of dvdp

The crackling is audible on changes in higher volume levels...on recordings which have silent passages/very few instruments its prominent and on heavy recordings its tough to make out 'cause there's quite a bit of background noise contributing to this melee at such volumes..

Hmm..I'm still unable to isolate the problem after spending quite a lot of time..
sivat
Stammgast
#6 erstellt: 02. Okt 2007, 02:47

Voodoo_CHild schrieb:

Savyasaachi schrieb:
This is most definitely a grounding problem.


Saachi,

Assuming its the ground...any leads on what can be done, how/what to check..etc?

Few more(!)things I've tried so far:

Amp is directly plugged to the wall socket and the dvdp is connected thru a v-guard stabilizer to a different connector on the same wall socket. I removed the v-guard and plugged the dvdp directly to the wall...and I get a mild shock if I touch the top of dvdp

The crackling is audible on changes in higher volume levels...on recordings which have silent passages/very few instruments its prominent and on heavy recordings its tough to make out 'cause there's quite a bit of background noise contributing to this melee at such volumes..

Hmm..I'm still unable to isolate the problem after spending quite a lot of time.. :?


I don't think this is a simple ground problem. Please take the amp to a qualified tech center.
myriad
Ist häufiger hier
#7 erstellt: 02. Okt 2007, 17:22

Voodoo_CHild schrieb:

Savyasaachi schrieb:
This is most definitely a grounding problem.


Saachi,

Assuming its the ground...any leads on what can be done, how/what to check..etc?

Few more(!)things I've tried so far:

Amp is directly plugged to the wall socket and the dvdp is connected thru a v-guard stabilizer to a different connector on the same wall socket. I removed the v-guard and plugged the dvdp directly to the wall...and I get a mild shock if I touch the top of dvdp

The crackling is audible on changes in higher volume levels...on recordings which have silent passages/very few instruments its prominent and on heavy recordings its tough to make out 'cause there's quite a bit of background noise contributing to this melee at such volumes..

Hmm..I'm still unable to isolate the problem after spending quite a lot of time.. :?



Voodoo,
Getting a mild shock when touching dvdp is because there's current in the chasis.
DVD players and Nad amps have two prong plugs. They need to be grounded if there's current in the chasis.You have to ground any one component in the chain by connecting a wire from the mains ground to your component's chasis.
bombaywalla
Stammgast
#8 erstellt: 02. Okt 2007, 20:43

Voodoo_CHild schrieb:

Savyasaachi schrieb:
This is most definitely a grounding problem.


Saachi,

Assuming its the ground...any leads on what can be done, how/what to check..etc?

Few more(!)things I've tried so far:

Amp is directly plugged to the wall socket and the dvdp is connected thru a v-guard stabilizer to a different connector on the same wall socket. I removed the v-guard and plugged the dvdp directly to the wall...and I get a mild shock if I touch the top of dvdp

The crackling is audible on changes in higher volume levels...on recordings which have silent passages/very few instruments its prominent and on heavy recordings its tough to make out 'cause there's quite a bit of background noise contributing to this melee at such volumes..

Hmm..I'm still unable to isolate the problem after spending quite a lot of time.. :?



I agree with Saachi that this is a grounding issue esp when you wrote that you got a mild shock from the DVD player when plugged into the wall directly. That, as myriad wrote, implies that the DVDP chassis is not grounded & that you have current in the chassis. Not good!
It also seems to imply to me that there is a voltage drop between the DVDP chassis & the Neutral line & that difference in potential is causing a current flow.


I am also surprised that despite having a 2-prong plug you do not have a ground. In residential electrical wiring they short Earth to Neutral so the Neutral line should have been giving you a ground.
Now, in India, anything is possible! The wiring in your house could be screwed up (as it is in many other houses across the country) & the faulty house wiring is your culprit.
Get a qualified technician in & ask him to verify the wiring.
Amp_Nut
Inventar
#9 erstellt: 03. Okt 2007, 03:50
1. As a first step, reverse the 2 pin DVD player plug, at he wall outlet.

MOST DVD Players often present a live chasis. Not Good

2. Remove the DVD player, and plug in an iPod temporarily, and see if the problem goes away....

Do revert.
anto
Schaut ab und zu mal vorbei
#10 erstellt: 03. Okt 2007, 06:06

and I get a mild shock if I touch the top of dvdp

I had the same problem and it got fixed when I reversed the way in which i plugged in the socket. Just check whether the Phase and Neutral marking on the plug matches with the Actual Phase and Neutral connection inside the socket.

,
Anto
Savyasaachi
Inventar
#11 erstellt: 03. Okt 2007, 07:45
I just know that it is a grounding problem because i had it but it was not a problem with my mains wiring(i didn't have a live chassis, unlike you). It was more so with my internal wiring.
Do revert back after trying out what Bombaywalla, ampnut and anto have suggested. I am more than a bit curious.
Voodoo_CHild
Stammgast
#12 erstellt: 03. Okt 2007, 12:11
Thanks guys for the suggestions...will try them all later tonight and post the results.

In the meanwhile, I guess I've isolated the issue...I'm still unsure about my ears...had goofed up a few things nothing serious though

Kamal
Stammgast
#13 erstellt: 03. Okt 2007, 14:32

I'm still unsure about my ears

OMIGOD!!
Was the buzz in your ears?
Take care,pal, & get well soon!


[Beitrag von Kamal am 03. Okt 2007, 14:33 bearbeitet]
Voodoo_CHild
Stammgast
#14 erstellt: 04. Okt 2007, 19:58
Results are out..

First things first..thanks Kamal for your kind words..I'm on the road to recovery

Coming back, this time I asked my brother who has no idea about all this to help me out...just wanted to ascertain that if he too finds the same issue I was complaining about...I also found it tiring to listen and spot the crackling at higher volumes especially when using headphones...more to do with my 'not so good' health nowadays.

As suggested, I reversed the dvdp 2 pin plug at the wall socket and there wasn't any kind of shocks whatsoever when I touch the top of my dvdp...mild or powerful

I asked my brother and my Mom to have a go too...neither of them received any shock treatments

Later, I reverted the plug back to its earlier position and checked...was surprised, no shocks now too!

My Mom was of the opinion that it may have been static discharge which I had experienced earlier...touching the dvdp chassis she drew comparison to polyester clothing

There are no markings on the plug to show which one's live and which one's neutral...found this (http://en.wikipedia.org/wiki/Domestic_AC_power_plugs_and_sockets)
So it doesn't really matter which way you connect a two pin plug, is it?

Also, when the amp was in standby mode, I received a bit more than mild shock when I accidentally touched the source input terminals at the back of the amp. Is this normal? From then on I switched off the mains completely before connecting anything.

I don't yet have a digital player, so got another dvdp from my friend to check if there's anything wrong with my existing dvdp..

After a couple of hours of swapping amps/dvdps and listening with both loudspeakers and headphones, we both figured out it was the amp..

..and next comes the interesting part..

'audible crackling on volume knob changes at higher volume levels' problem was found with my friend's nad c352...quite prominent plus the background noise

In my nad c325, its only the background noise...we played around with the volume knob for quite a few times to conclude that the knob rotation by itself didn't produce a crackling effect which is the case with my friend's amp, but with increase in volume noise became more and can be heard well from tweeters.

So I suspect it still maybe an earthing issue as mentioned by Saachi or my power line is very noisy.

In any case, I've asked our electrician to have a look over the weekend.

I mailed my friend whos abroad right now for a few months, asked him if he was aware of this, said he was and once he comes back next month will get it fixed. He had left the amp here with his brother at home who uses it very rarely to play some mp3s and is a casual listener

Anyway, looking forward to a good weekend after a hectic week!

Amp_Nut
Inventar
#15 erstellt: 05. Okt 2007, 02:45


As suggested, I reversed the dvdp 2 pin plug at the wall socket and there wasn't any kind of shocks whatsoever when I touch the top of my dvdp...mild or powerful

Later, I reverted the plug back to its earlier position and checked...was surprised, no shocks now too!


I suspect that the 1st time around ( when you DID reciev the mild shock, you were wearing Leather footware or barefoot.

When no shock.... Ruber footware... ?

Also, no chance to substitute your source (DVD Player) with a battery operated device such as an iPod ?
Voodoo_CHild
Stammgast
#16 erstellt: 05. Okt 2007, 06:00

Amp_Nut schrieb:


As suggested, I reversed the dvdp 2 pin plug at the wall socket and there wasn't any kind of shocks whatsoever when I touch the top of my dvdp...mild or powerful

Later, I reverted the plug back to its earlier position and checked...was surprised, no shocks now too!


I suspect that the 1st time around ( when you DID reciev the mild shock, you were wearing Leather footware or barefoot.

When no shock.... Ruber footware... ?

Also, no chance to substitute your source (DVD Player) with a battery operated device such as an iPod ?


Barefoot all the times..

Maybe I can get a digital player (I also have a sony discman) from one of my friends...not an issue, but I think they need a different type of connectors to connect to the amp. I don't have them...just the regular pair of RCA interconnects. Correct me, if I'm wrong.

I'm sure its not the dvdp issue, 'cause the sound & noise issues mentioned were present irrespective of any dvdp connected...oh yes, both the dvdps are of the same make/model no.

Edit:
Also, when the amp was in standby mode, I received a bit more than mild shock when I accidentally touched the source input terminals at the back of the amp. Is this normal?


[Beitrag von Voodoo_CHild am 05. Okt 2007, 06:01 bearbeitet]
Amp_Nut
Inventar
#17 erstellt: 05. Okt 2007, 06:07


Barefoot all the times..


Please Avoid Bare feet. Can be letheal.... not just from yr stereo... ANY electically leaky appliance can be potentially lethal...




Edit:
Also, when the amp was in standby mode, I received a bit more than mild shock when I accidentally touched the source input terminals at the back of the amp. Is this normal?


No ! Its Not Normal, It should NOT be so...
anto
Schaut ab und zu mal vorbei
#18 erstellt: 05. Okt 2007, 06:10
It will be better if you use the electric test pen.
In my case there was slight glow in the test pen and after I reversed the plug prongs the glow disappeared.
Voodoo_CHild
Stammgast
#19 erstellt: 05. Okt 2007, 06:45

Amp_Nut schrieb:

Please Avoid Bare feet. Can be letheal.... not just from yr stereo... ANY electically leaky appliance can be potentially lethal...


Point noted Sir...Will be careful from now on


anto schrieb:
It will be better if you use the electric test pen.
In my case there was slight glow in the test pen and after I reversed the plug prongs the glow disappeared.


I have asked my electrician to come over tomorrow, will check then and see if he gets any kind of shock treatments

Anyone aware of any workaround to minimize the background noise with the existing wiring setup?
aks07
Stammgast
#20 erstellt: 05. Okt 2007, 12:59
The buzz is in form of a single tone or contains harmonics as well ? That will help to rule out other things.

Frankly, its difficult to suggest a reason for the buzz without actually looking at the equipment. It can range from a faultily capacitors to a grounding interference. Is your electrical wiring checked and confirm to the standard installation procedure? Do you live in an apartment block where a single junction board is shared by many households? Is the safety earth present and functioning properly? Is your DVD connected to a TV set also? Does the TV set has a Cable connection? Remove the DVD player to another room or building and check if electrical leakage persists.

Getting a shock when you touch amp RCA input means 100% chances of a fault in your electrical wiring. As bombaywalla-ji has suggested the neutral and earth connections may have been sorted together. Its a standard practice of the semi-literate electricians. Or the earth connection is not OK. If you are handy with a multimeter perhaps we can suggest some steps for you to investigate- both for your household wiring and your audio system. BUT ONLY IF YOU KNOW THE BASIC ELECTRICAL SAFETY PRECAUTIONS.

And lastly a gentle suggestion - Using your family folks to check out electrical leakage in a device is most certainly NOT OK ! Use a neon tester instead. Never forget to wear rubber footwear and keep one hand in your pocket when poking around an electrically operated device. Be safe always. A fancy audio system is not much use when its owner is not longer around to enjoy it.
Voodoo_CHild
Stammgast
#21 erstellt: 05. Okt 2007, 15:39

aks07 schrieb:
The buzz is in form of a single tone or contains harmonics as well ? That will help to rule out other things.

Well...its a single tone, similar to a crackling/crunching noise, lasts for a second or so, happens only when the volume knob on the amp is operated, audible clearly at higher volumes especially when the knob's turned clockwise in steps to increase the sound level gradually...and this is as much as I can explain


aks07 schrieb:
Is your electrical wiring checked and confirm to the standard installation procedure?

Since I'm unaware of the standards, I'll ask the same question tomorrow to my electrician and find out


aks07 schrieb:
Do you live in an apartment block where a single junction board is shared by many households?

No, I live in an independent house.


aks07 schrieb:
Is the safety earth present and functioning properly?

Safety earth's present, 100% sure...
functioning properly...I don't know, need to check.


aks07 schrieb:
Is your DVD connected to a TV set also? Does the TV set has a Cable connection? Remove the DVD player to another room or building and check if electrical leakage persists.


dvdp is connected to the TV which has a cable connection.
Havent tried another room so far...will add that 'To Do' list...

Thanks for your suggestions/precautions.
Will 'play safe' from now on
ani
Stammgast
#22 erstellt: 05. Okt 2007, 15:47
Hello voodoo,

Nice to see that you and family is safe and sound

1. The buzz you hear from the speaker while operating the volume control a constant one?

2. Is the buzz audible when you touch the volume control knob?

3. Since you said that the buzz is there even without connecting the DVD player, the origin of Buzz is from the amp. If you increase the volume to high level leaving the input of the amp open, ie without any source connected the amp will pick up RFI/EMI and the same can be heard as BUZZ or HUM from the speakers.

4. If you have very dirty mains power the same can cause buzz , but it will there continuously.

5. Is your amp having 3pin or 2 pin mains plug? if it is two pin the mild shock you might have felt is due to induction which may go off if you the mains plug is plugged in by rotatiing it 180degree.


Hope this may be of some help to you,
Regards
Anil
Neutral
Stammgast
#23 erstellt: 06. Okt 2007, 07:09
When my amp gave me noise problems (when turning its volume controls) I had the dealer spray the pots with cleaning fluid. Does this amp just need servicing? Is it exposed to high levels of dust & moisture?
Voodoo_CHild
Stammgast
#24 erstellt: 06. Okt 2007, 08:24
Hi Anil,
Thanks for your concern, everyones fine

1. The buzz (I prefer describing it as a crackling/crunching noise, not the humming tone/noise) from the speaker increases the more I turn the knob clockwise to up the volume level.
But the duration of the buzz remains almost constant around a second or so.
At lower volumes its difficult to make out, typically below 9'o clock position.
I've tried only upto 1'o clock position, after which its again tough to make out due to the high sound levels plus some amount of background noise (probably from the recordings) creeping in.
If I dont operate the knob and keep the volume level constant at, say 10'o clock position, no buzz is heard.

2. No buzz is present if I just touch the volume control knob.
Only during operation, either manually or from the remote control.

3. With an open input, Amp's residual noise/interferences is audible only beyond 3'o clock to the volume control turned fully clockwise. This buzz is different from the one I get when operating the volume control.

4. Mains are pretty normal, just like any decent household...and I get the continuous buzz youre referring to only at very higher volumes which I normally dont listen to. I also suspect some inferior recordings contribute a lot to the background noise or maybe even the interconnects 'noise rejection' capability

5. My amp (as well as my friend's amp) has a 2 pin mains plug. Didnt find any difference rotating the plug, anyway electrician should be here today, will ask him to verify.

Your queries certainly helped me understand things better!
Hope my answers to your queries are satisfactory

Cheers!
Voodoo_CHild
Stammgast
#25 erstellt: 06. Okt 2007, 08:25

Neutral schrieb:
When my amp gave me noise problems (when turning its volume controls) I had the dealer spray the pots with cleaning fluid. Does this amp just need servicing? Is it exposed to high levels of dust & moisture?


No, its not exposed to moisture and not too dusty either...I maintain most of my stuff pretty clean and I guess most would, considering the time & money gone in
aks07
Stammgast
#26 erstellt: 06. Okt 2007, 10:02

Voodoo_CHild schrieb:
Hi Anil,
Thanks for your concern, everyones fine

1. The buzz (I prefer describing it as a crackling/crunching noise, not the humming tone/noise) from the speaker increases the more I turn the knob clockwise to up the volume level.
But the duration of the buzz remains almost constant around a second or so.
At lower volumes its difficult to make out, typically below 9'o clock position.
I've tried only upto 1'o clock position, after which its again tough to make out due to the high sound levels plus some amount of background noise (probably from the recordings) creeping in.
If I dont operate the knob and keep the volume level constant at, say 10'o clock position, no buzz is heard.

2. No buzz is present if I just touch the volume control knob.
Only during operation, either manually or from the remote control.

3. With an open input, Amp's residual noise/interferences is audible only beyond 3'o clock to the volume control turned fully clockwise. This buzz is different from the one I get when operating the volume control.

4. Mains are pretty normal, just like any decent household...and I get the continuous buzz youre referring to only at very higher volumes which I normally dont listen to. I also suspect some inferior recordings contribute a lot to the background noise or maybe even the interconnects 'noise rejection' capability

5. My amp (as well as my friend's amp) has a 2 pin mains plug. Didnt find any difference rotating the plug, anyway electrician should be here today, will ask him to verify.

Your queries certainly helped me understand things better!
Hope my answers to your queries are satisfactory

Cheers!


1. From your description is appears to be either an intermittent solder joint or a fault pot. Ask a qualified tech to have a look inside. If it is a circuit problem, he will (hopefully) have the proper tools to trace and identify the cause

2. Is it a motorised volume pot?

3. Short the input to ground. Crank up fully the volume pot. If you hear noise (any kind – save a little hiss from the tweeter), there is a problem. Modern amps with their published specs should have ZERO audible noise.

4. If it passes the test on point 3 above THEN recording is an issue.

5. Your amp should atleast have a ground connection lug. Connect that to a working ground. The mild shock issue should be taken care of.

Slighly off-topic but most recordings have a little background noise. In fact this is deliberate else the recordings will sound "dry". Check out the recordings from the 80's era. Sound Engineers produced “Zero background Noice” recordings. No wonder 80's was the time when all time worst recordings were made. Thankfully, by 90's sound engineers started injecting some background noise to recordings, thus imparting some body to the source material.
Kamal
Stammgast
#27 erstellt: 06. Okt 2007, 10:08

4. If it passes the test on point 3 above THEN recording is an issue

Is that "grounding"?
aks07
Stammgast
#28 erstellt: 06. Okt 2007, 10:24

Kamal schrieb:

4. If it passes the test on point 3 above THEN recording is an issue

Is that "grounding"?

No I meant recording as VC-ji was suspecting that a possible cause. If his amp is not producing any noise of its own, then the recording backgroud noise is the "noise" he is hearing. With no source and the input grounded amp should not produce any noise.
thanks
Voodoo_CHild
Stammgast
#29 erstellt: 06. Okt 2007, 18:28

aks07 schrieb:
1. From your description is appears to be either an intermittent solder joint or a fault pot. Ask a qualified tech to have a look inside. If it is a circuit problem, he will (hopefully) have the proper tools to trace and identify the cause

2. Is it a motorised volume pot?

3. Short the input to ground. Crank up fully the volume pot. If you hear noise (any kind – save a little hiss from the tweeter), there is a problem. Modern amps with their published specs should have ZERO audible noise.

4. If it passes the test on point 3 above THEN recording is an issue.

5. Your amp should atleast have a ground connection lug. Connect that to a working ground. The mild shock issue should be taken care of.

Slighly off-topic but most recordings have a little background noise. In fact this is deliberate else the recordings will sound "dry". Check out the recordings from the 80's era. Sound Engineers produced “Zero background Noice” recordings. No wonder 80's was the time when all time worst recordings were made. Thankfully, by 90's sound engineers started injecting some background noise to recordings, thus imparting some body to the source material.

1. I am thinking on the same lines as your point no.1

2. Yes, its a motorized volume pot.

3. 'With an open input, Amp's residual noise/interferences is audible only beyond 3'o clock to the volume control turned fully clockwise' - Yesterday, I did this with my headphones on.

Today, tried the same with loudspeakers connected. With the volume fully up, a little hiss from the tweeters is heard only when I put my ears next to the tweeters. I moved my ears just about a foot away, noise is not audible...very silent overall.

I guess it should be OK then..

Short the input to ground - I didnt short the input to the ground because I didnt have any wires to do that.
Any other way, please let me know.

4. I presume 3 is passed, so if its the recordings...I'm not too bothered, can live with it

5. From the look of it, the amp doesnt have any ground connection lug...rear panel has the following connectors:

IR input/output
Disc input
CD input
Video input
AUX input
Tuner input
Tape 1 in/out
Tape 2 in/out
12V Trigger output
Pre out
Main in
Speaker terminals

The trivia about injecting noise to the recordings was an interesting one...wasnt aware of that before
Voodoo_CHild
Stammgast
#30 erstellt: 08. Okt 2007, 05:42
The electrician was at my place yesterday...

First thing I asked was if the Earth and Neutral are shorted...he said 'No', and I got it confirmed by asking him to open and check the connections at the back of the switchboard socket. We verified that the Earth and Neutral were not connected together. He said Earth connections from all the switchboards are in turn joined at junction boards before finally going down to the Earthing pit. I forgot to ask if at any point in the wiring, the Neutral line is connected to the Earth.

We checked the Neutral voltage a few times (I think its the zero voltage reference, when measured wrt Earth?). Most times it was close to Zero (varied between 0 to 4V) on the multimeter. The Live voltage (wrt Neutral?) was around 240V. When asked about variations, he said due to AC power lines not providing a constant voltage all the time

Next thing he checked was DVDP chassis and the Amp terminals, both times the neon tester glowed, confirming there was current in the chassis of both the devices.

Since both are connected in loop, we unplugged the DVDP and connected to a different socket in another room and checked, the same neon glow.

I asked him to check the voltage drop between the DVDP chassis and the Neutral, it was around 6V responsible for current in the DVDP chassis.

Then checked plugging the Amp alone, neon glowed again at the Amp terminals.

He decided to ground DVDP by connecting a wire from the Earth point to DVDP chassis. Since Amp is connected to the DVDP, it would also take care of it. Later, we checked both devices and there wasnt any neon glow on the tester at any point...implied no more 'mild' shocks

My friends Amp, still though has that original problem of buzz with the volume knob operation...I'll ask him or I myself will get it checked with a qualified technician.

My own Amp doesnt buzz around with volume changes and I also noticed that the background noise (tiny itsy bitsy crackles!) at higher volumes has come down a bit after this earthing issue was sorted out
aks07
Stammgast
#31 erstellt: 08. Okt 2007, 10:44
Good !
One of your problems is taken care of. I am surprised that the NAD did not have an earth prong. I have minimum experience with modern amps, but is it a standard practice? Even my Shanling CDP has a 3-prong AC in.

All these inductive leakage would not have happened if your set-up was properly grounded. Grounding needs to be done carefully as there is a possibility of picking up hum due to a loop. Some amps even have a “ground break” switch in the back.

Those “tiny itsy bitsy crackles” are RF noise. Think of your AC line as a long extended radio antenna picking up all shorts of interference on its journey from the power station to your amp. Nowadays most equipments (printer, faxes, UPC, etc) are required to have an in-line RFI filter. The RF noise is at its minimum (power is cleanest) in the off-peak hours. Try listening to your audio system after midnight.

For your other noise problem its best to have the NAD repair guy have a look. All the best !
Voodoo_CHild
Stammgast
#32 erstellt: 08. Okt 2007, 13:47

aks07 schrieb:
Good !
One of your problems is taken care of. I am surprised that the NAD did not have an earth prong. I have minimum experience with modern amps, but is it a standard practice? Even my Shanling CDP has a 3-prong AC in.

Since most of the modern electronic components are manufactured in Asian countries (both NAD & Philips I have are manufactured in China), I think they're quite content to provide 2-pin plugs which aids in cutting costs and even the local laws may permit using them instead of insisting on 3-pin plugs. Maybe, inturn these are sold in Asian countries like India etc. and I'm not too sure if theyre allowed to sell high powered equipments which use 2-pin plugs in UK, US and EU, except shavers/hair dryers.

aks07 schrieb:

All these inductive leakage would not have happened if your set-up was properly grounded. Grounding needs to be done carefully as there is a possibility of picking up hum due to a loop. Some amps even have a “ground break” switch in the back.

Can you please elaborate on that 'loop' condition and its probability of occurrence? Did you mean its better off each component in the chain grounded separately, rather than the way my electrician has done right now? I didnt find any 'ground break' switch on the rear panel of my Amp, and its not mentioned on the manual either.

aks07 schrieb:
Those “tiny itsy bitsy crackles” are RF noise. Think of your AC line as a long extended radio antenna picking up all shorts of interference on its journey from the power station to your amp. Nowadays most equipments (printer, faxes, UPC, etc) are required to have an in-line RFI filter. The RF noise is at its minimum (power is cleanest) in the off-peak hours. Try listening to your audio system after midnight.

I have a doubt...there is a cellphone tower setup by Airtel around 100m away from my house, shared by all the cellular operators. Is there a possibility of the AC lines picking up some interference from that? Or is the operational frequency range of cellphone communication different, so that it would not mix up with audio frequency spectrum?

Thanks!
Kamal
Stammgast
#33 erstellt: 08. Okt 2007, 16:13

there is a cellphone tower setup by Airtel around 100m away from my house

Aha!
This could be a culprit.
You would need to rule this out.
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