My initial impressions switching from Parasound Halo to an ATI AT524nc

RichB

RichB

Audioholic Field Marshall
I'm not sure what to make of it. Those sine waves are distorted, but I'm not residential power knowledgable. I'd call the power company, tell them you've had issues with noisy transformers, and ask them if they'll do an assessment.
At this point, I don't have noisy transformers. The Oppo Sonica DAC and UPD-205 have transformers don't make noise.
I don't have any large transformers amps and the AHB2s are silent.
My friend moved to OLED and that solved his problem. That and he moved to the AHB2s as well.
The AT525NC is very quiet as well.

Here is what AH experience with the Monolith 7-chanel amp:
Monoprice Monolith 7-Channel Amplifier Review | Audioholics

If you have dimmers in your house or the issue known as DC offset then the Monolith’s massive transformers may start to hum. They did in my case when the lights on my microwave were on and set to low. To be clear, this isn’t a design problem with the Monolith. To fix the humming, I plugged the Monolith into Emotiva’s CM2 AC line restoration and common mode filter system. This two-outlet receptacle is specially designed to eliminate DC offset issues without limiting current or dynamics.
Some amps are more susceptible to power issues than others and it you don't need exceptional hearing to detect hum.

- Rich
 
Irvrobinson

Irvrobinson

Audioholic Spartan
At this point, I don't have noisy transformers. The Oppo Sonica DAC and UPD-205 have transformers don't make noise.
I don't have any large transformers amps and the AHB2s are silent.
My friend moved to OLED and that solved his problem. That and he moved to the AHB2s as well.
The AT525NC is very quiet as well.

Here is what AH experience with the Monolith 7-chanel amp:
Monoprice Monolith 7-Channel Amplifier Review | Audioholics



Some amps are more susceptible to power issues than others and it you don't need exceptional hearing to detect hum.

- Rich
Rich, sine wave distortion can shorten the life of electric motors too. I'm simply not an expert, so I don't know if the distortion you displayed is significant. You probably have some expensive motors in your home, and most utilities do an assessment for free.
 
RichB

RichB

Audioholic Field Marshall
Rich, sine wave distortion can shorten the life of electric motors too. I'm simply not an expert, so I don't know if the distortion you displayed is significant. You probably have some expensive motors in your home, and most utilities do an assessment for free.
Probably so.
I cannot shut off my 400 amp service. It cannot be shutoff by pulling the meter.
I wanted to install a Generac but this greatly complicates the installation.
Calling the electric company was not rewarding, I got routed around and hung up on.

- Rich
 
Irvrobinson

Irvrobinson

Audioholic Spartan
Probably so.
I cannot shut off my 400 amp service. It cannot be shutoff by pulling the meter.
I wanted to install a Generac but this greatly complicates the installation.
Calling the electric company was not rewarding, I got routed around and hung up on.

- Rich
400amp service. Very impressive. Why can't it be shut off?

Of course you need a Generac unit! GNRC has been very, very good to me.
 
RichB

RichB

Audioholic Field Marshall
400amp service. Very impressive. Why can't it be shut off?

Of course you need a Generac unit! GNRC has been very, very good to me.
The power saga follows :)

The house was built in the 80's with electric heat.
When that proved the be too expensive, hydro-air via propane was added and the electric is no longer used.
Some has been removed and some is shut off at the breakers. Needless to say, there is power to spare.
Three dedicated 20-amp circuits drive the HT along with 2 15 amp plugs, circuits unknown.

About 10 years ago, one of the 200 amp breakers started smoking. It could not be replaced at the box because the replacement fed from the side and the wire did not reach. My electrician looked meter and at it and the meter was wired in parallel.

I called the Electric company and they informed me that I would need to get a permit, power would be shut down, After the work is completed an inspection is needed to turn the power back on. I asked what about if it was an emergency. He said that I would have to call the fire department.

With my electrician at the ready and parts in hand, we called the fire department and he came, the police, and town inspector. They did know which house to turn off with the pole (underground) so they shutdown 4 houses. The electrician worked fast and in 22 minutes (measured by my UPS) we were up and running.

So when you say call the electric company, I have low expectations.

If I go with a Generac, it means a permit, power shutoff, and likely dual transfer switches. It will be a production. The total cost is 2X the generator.

- Rich
 
Irvrobinson

Irvrobinson

Audioholic Spartan
The power saga follows :)

The house was built in the 80's with electric heat.
I had one of those. I was young and naive and didn't think it would be that bad. My first winter monthly electric bill was nearly $500, in 1982. That was big money for me back then.

When that proved the be too expensive, hydro-air via propane was added and the electric is no longer used.
Some has been removed and some is shut off at the breakers. Needless to say, there is power to spare.
Three dedicated 20-amp circuits drive the HT along with 2 15 amp plugs, circuits unknown.

About 10 years ago, one of the 200 amp breakers started smoking. It could not be replaced at the box because the replacement fed from the side and the wire did not reach. My electrician looked meter and at it and the meter was wired in parallel.
This makes no sense to me. It sounds like a big code violation and safety issue.

I called the Electric company and they informed me that I would need to get a permit, power would be shut down, After the work is completed an inspection is needed to turn the power back on. I asked what about if it was an emergency. He said that I would have to call the fire department.

With my electrician at the ready and parts in hand, we called the fire department and he came, the police, and town inspector. They did know which house to turn off with the pole (underground) so they shutdown 4 houses. The electrician worked fast and in 22 minutes (measured by my UPS) we were up and running.
What a poop-show.

So when you say call the electric company, I have low expectations.

If I go with a Generac, it means a permit, power shutoff, and likely dual transfer switches. It will be a production. The total cost is 2X the generator.

- Rich
Like I said, this set-up sounds like a basic safety issue. I'd take the pain and have the meter and the breaker boxes redone.

Those other three homeowners must have been very pleased. I hope they got fair warning.
 
P

PENG

Audioholic Slumlord
Rich, sine wave distortion can shorten the life of electric motors too. I'm simply not an expert, so I don't know if the distortion you displayed is significant. You probably have some expensive motors in your home, and most utilities do an assessment for free.
That can happen but would be rare even in factories let alone residential areas. I say this based on my many years of experience dealing with motors and transformers, large and small, fixed or variable speed etc. Again, it could, and surely had happened to equipment/devices in people's home too, perhaps sometimes without being noticed.

I would think if it is a serious enough issues, Rich would have noticed issues with other devices in the house as you alluded to. If it is not a serious issues, say in Rich's case, then the power company won't do anything if the "distortion" is within acceptable limits. I think Rich likely could have fixed the issue with a good quality DC blocker for his ATI amps that have large transformers in them but of course he no longer have t worry about them any more.
 
P

PENG

Audioholic Slumlord
I called the Electric company and they informed me that I would need to get a permit, power would be shut down, After the work is completed an inspection is needed to turn the power back on. I asked what about if it was an emergency. He said that I would have to call the fire department.
If the job had been inspected by the power company then it should comply with code now. It didn't sound like it was in compliance before that episode though.

One of the heightened concerns (aside from shock hazard) in recent years about even a 208/120 V main breaker or disconnect panel is "arc flash". Residential 208/120 V systems may not an issue in terms of arc flash risk but it still depends on the fault level available and that depends on the size of the transformer that feeds the panel. If you have multiple disconnects rated 200 and 400A, there may be a chance..

Home owners are typically not trained (I was:D, by professional/job requirement, and I did training too so I know something about this) and don't have the necessary PPE, so even now you may or may not have to call the power company and/or fire department if you need to turn the switch in an emergency. Can't say for sure without knowing more about your power equipment and the feed, but it may be good idea to call them and ask the same question, what do in an emergency if you have to turn the main switch off. That's just in case, you never know..
 
RichB

RichB

Audioholic Field Marshall
If the job had been inspected by the power company then it should comply with code now. It didn't sound like it was in compliance before that episode though.

One of the heightened concerns (aside from shock hazard) in recent years about even a 208/120 V main breaker or disconnect panel is "arc flash". Residential 208/120 V systems may not an issue in terms of arc flash risk but it still depends on the fault level available and that depends on the size of the transformer that feeds the panel. If you have multiple disconnects rated 200 and 400A, there may be a chance..

Home owners are typically not trained (I was:D, by professional/job requirement, and I did training too so I know something about this) and don't have the necessary PPE, so even now you may or may not have to call the power company and/or fire department if you need to turn the switch in an emergency. Can't say for sure without knowing more about your power equipment and the feed, but it may be good idea to call them and ask the same question, what do in an emergency if you have to turn the main switch off. That's just in case, you never know..
The current code calls shutoffs outside the home. Thus far, I have not found a master electrician to take on the job.
I could put the transfer switch outside the house which could solve all the problems.

- Rich
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
That can happen but would be rare even in factories let alone residential areas. I say this based on my many years of experience dealing with motors and transformers, large and small, fixed or variable speed etc. Again, it could, and surely had happened to equipment/devices in people's home too, perhaps sometimes without being noticed.

I would think if it is a serious enough issues, Rich would have noticed issues with other devices in the house as you alluded to. If it is not a serious issues, say in Rich's case, then the power company won't do anything if the "distortion" is within acceptable limits. I think Rich likely could have fixed the issue with a good quality DC blocker for his ATI amps that have large transformers in them but of course he no longer have t worry about them any more.
So what's the take-away message with transformer hum?

Some people are more sensitive to hearing the hum, while some are not as sensitive to hearing it?

Some people many have electrical environmental issues (electricity going into house, home electric circuits) that can exacerbate the hum?

Some people are not as sensitive to the hum noise PLUS they have a good electrical environment so they really can't hear the hum?
 
RichB

RichB

Audioholic Field Marshall
So what's the take-away message with transformer hum?

Some people are more sensitive to hearing the hum, while some are not as sensitive to hearing it?

Some people many have electrical environmental issues (electricity going into house, home electric circuits) that can exacerbate the hum?

Some people are not as sensitive to the hum noise PLUS they have a good electrical environment so they really can't hear the hum?
All transformers hum.
The degree to which they hum vary from manufacturer, product line, and also unit to unit.
Transformers are sensitive to power issues that may be external (from the power company) or internally dimmers, motors, fans :))).

Some amplifiers are virtual immune because they do not use linear power supplies (though they can have other issues) or because they have circuitry to that rejects DC.

As a result, you can have one person reporting that their amps is virtually silent while another is upset by audible hum.
Both can be valid observations. For the person experiencing hum, the observation by others of a quiet amp are of little comfort.

I've not heard reports of mechanical hum from owners of class-d or amplifiers with well engineered SMPSs.

- Rich
 
P

PENG

Audioholic Slumlord
So what's the take-away message with transformer hum?

Some people are more sensitive to hearing the hum, while some are not as sensitive to hearing it?

Some people many have electrical environmental issues (electricity going into house, home electric circuits) that can exacerbate the hum?

Some people are not as sensitive to the hum noise PLUS they have a good electrical environment so they really can't hear the hum?
I said some may be more sensitive to hearing the hum because I wanted to be diplomatic about it, instead of saying things like: you didn't listen careful enough, close enough, room's not quiet enough, you are exaggerating, or worse, you must be deaf:p. RichB called me out on that so okay now I am being blunt.., sorry!

Yes, "electrical environmental issues" including those related to the incoming power that you can't do much about it unless it is serious/obvious, or caused by your other devices in the house, are likely the culprit, more often than not.

To your last question, even under the best scenario, that is, the power source is super clean, transformers will still hum but the good ones fed with clean power source will only hum loud enough to be audible with you ears touching the chassis nearest to the transformer. And, all else being equal, larger transformers hum louder.

I posted some links earlier so one can dig into why they hum. Without digging into the details, it should be easy to understand if something vibrates, there will be noise. Obviously transformer core laminate sheets and windings must vibrate with the AC so it will make noise, but the noise could be kept to the point you may consider it "silent".

If you look at Denon's marketing hype about their sand type Aluminum casting filled with resin approach in "eliminating" vibration. That made sense to me and it is believable that such expensive transformers should be near silent, my only issue is with the word "eliminate". If they chose to be more honest, they would have substituted it with "substantially reduce..", or even "minimize", but then I would be splitting hair.

May be its time to agree that if one cannot hear the hum regardless, or can hear it only with the ears touching and with the room under near silent condition, then the transformer is "silent". I am totally fine with that, and I am sure you are as well.

Since your amps are all hum free, and knowing you have much more than 1 or 2 amps, you obviously have clean power coming into your electrical panel, lucky you!
 
P

PENG

Audioholic Slumlord
All transformers hum.
The degree to which they hum vary from manufacturer, product line, and also unit to unit.
Transformers are sensitive to power issues that may be external (from the power company) or internally dimmers, motors, fans :))).

Some amplifiers are virtual immune because they do not use linear power supplies (though they can have other issues) or because they have circuitry to that rejects DC.

As a result, you can have one person reporting that their amps is virtually silent while another is upset by audible hum.
Both can be valid observations. For the person experiencing hum, the observation by others of a quiet amp are of little comfort.

I've not heard reports of mechanical hum from owners of class-d or amplifiers with well engineered SMPSs.

- Rich
Wow, so we actually were in agreement, except the BS on "some people are more sensitive....." on my part.:D:D
 
AcuDefTechGuy

AcuDefTechGuy

Audioholic Jedi
Wow, so we actually were in agreement, except the BS on "some people are more sensitive....." on my part.:D:D
However unlikely, but I would not RULE OUT the part about "hearing sensitivity", so I would not call it BS. :D

It's not like anyone has done a massive scale double-blind research into this topic. :D

I agree the overall home electrical environment is the salient factor.
 
Trell

Trell

Audioholic Spartan
However unlikely, but I would not RULE OUT the part about "hearing sensitivity", so I would not call it BS. :D

It's not like anyone has done a massive scale double-blind research into this topic. :D

I agree the overall home electrical environment is the salient factor.
When I was young I had excellent hearing but no money. In my dotage I'm loaded but I'm told that I should buy some hymens of Angles to restore my youthful hearing as pixie dust no longer works.

What a sad world we live n.
 
RichB

RichB

Audioholic Field Marshall
When I was young I had excellent hearing but no money. In my dotage I'm loaded but I'm told that I should buy some hymens of Angles to restore my youthful hearing as pixie dust no longer works.

What a sad world we live n.
When you can't hear 60Hz, it really is all over :)

- Rich
 
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P

PENG

Audioholic Slumlord
Its more like 120 Hz, the fundamental frequency of the noise from magnetostriction: the expansion and contraction of the iron core (laminations). So even easier to hear..
 
RichB

RichB

Audioholic Field Marshall
Its more like 120 Hz, the fundamental frequency of the noise from magnetostriction: the expansion and contraction of the iron core (laminations). So even easier to hear..
Yes, but that's not as funny.
Buzz that I have heard is not 60Hz either.

- Rich
 
P

PENG

Audioholic Slumlord
Perhaps move away from the null you are sitting in? :)
No need, Dirac Live will fix it for you.., for the money it should everything, even if Shady says (he just might) not possible.:D
 
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