Audioquest Niagara 7000 hum/buzz


Owners of the Audioquest Niagara 7000, I could sure use some help.

I now own a (used) Niagara 7000 that I like very much, except it buzzes. Sometimes quite loudly. It will buzz even if there is nothing plugged into it but at a much lower level. It seems that with it fully loaded up with tube mono blocks, powered subs and the rest of my system the buzz gets even worse. The buzz can be heard across the room some 15+ feet away.

I have contacted dealers for the product and some say it should be dead quiet while others say it is normal for it to buzz due to the isolation transformers inside.

What have you guys experienced?

I have also contacted Audioquest and the local rep for my area has provided some suggestions that didn’t help. Since I bought it used and I have changed the 20A IEC to a Furutech NCF 20A IEC, he calls it a modified used unit and will not issue a return authorization number for repair. Personally, I think that is pretty crappy, I am not asking for a freebie repair, just some help.

So, again, is it normal for the Niagara 7000 to buzz? Any other suggestion?


Thanks,

ozzy


ozzy

Showing 12 responses by jea48

ozzy OP

3,755 posts
05-31-2019 3:18pm


You know, it does hum more in the evening when we are watching a movie, so I will plug in the TV elsewhere tonight. Does it matter if the TV is plugged in but not turned on?

Just plugging the TV into a different circuit might help, but I doubt it. Your electrical service is fed from a common power source. The DC is going out on the AC mains. It may even be affecting your neighbors that are fed from the same utility power transformer that you are.

Does it matter if the TV is plugged in but not turned on?
Yes it may. The power supply may be powered when the unit is plugged into the wall outlet.

For a test tonight unplug the TV from the wall outlet. Check for hum/buzz from the Niagara 7000. If the 7000 doesn’t hum/buzz then you can try plugging the TV into a different circuit.

I do not have any experience with these products.

I would send an email and ask, if the TV is plugged into the unit will the unit block DC from going through the unit back out onto the AC mains power.
Make sure the unit is rated for the FLA or VA big enough for the load of the TV.


https://avahifi.com/products/humdinger-dc-line-blocker

https://emotiva.com/products/cmx-2


I know beans about this guy. Notice he does have a 100% feedback rating. Check his US buyer’s feedback ratings. You should also read what the guy says about sizing the unit for the load that will be connected to it.
I would want safety overload fusing protection on the AC line side of the unit.


https://www.ebay.com/itm/DC-trap-blocker-filter-for-toroidal-transformers-assembled-in-case-/1316546...


ozzy OP

3,753 posts
05-31-2019 11:33am

It seems to get louder when everything is on including a 85" UHD Samsung that draws quite a bit of current. It may be that I am overloading it. So, I will remove the subs from the Niagara.


ozzy,

Do you know if the transformer/s in the Niagara 7000 are toroidal power transformers?

Larger Toriods are more susceptible to buzz, vibrate, when there is DC offset on the AC mains. There is a very good chance the Samsung 85" UHD TV is the culprit causing the DC. Good chance it uses a switch mode power supply.

For a test unplug the Samsung TV from the AC power. Load the Niagara 7000 and then check for transformer/s buzzing/vibrating. If there is not any buzzing you might try a DC blocker on the Samsung TV. The blocker should stop the DC from going back out on the AC mains power. You will need to size the DC blocker for the FLA of the TV + a small fudge factor.

Something else that should work is a 1 to 1  single ended isolation power transformer to feed the TV. DC will not pass through the windings of an isolation transformer. Size the transformer for at least 125% of the FLA or VA rating of the TV.

** TRANSFORMER MUST BE an EI type transformer. NOT A TORIOD. A toriod would more than likely buzz, vibrate.



Jim
.
ozzy OP

3,769 posts
06-04-2019 2:36pm

Well I just received the Emotiva DC blocker and it did nothing. In fact with it plugged into the wall and the Niagara plugged into the Emotiva DC blocker the Emotiva unit got super hot!

@ozzy

Sounds like you are overloading the unit. What is the Emotiva rated for? Max connected load amps rating? Or max connected load volt amps rating? If you are overloading the blocker it will not block the DC offset. ( That is IF DC offset is causing the problem with the AQ 7000.)

Did you verify 100% the Samsung TV was the cause of the buzzing sound, by simply unplugging the TV from the AC mains AC power?

IF the TV is the culprit try plugging the TV into the Emotiva DC blocker. I would think it should block the DC from back feeding onto the AC mains. You could always ask Emotiva Tech Support services to find out for sure.


.


Found this.


Trouble-Shooting Guide

I hear a slight buzzing sound coming from the Niagara 7000. Is it damaged?

No, it’s not damaged (or, at least, damage is veryunlikely). If you’re in an extraordinarily quiet room and you hear this buzzing sound only when in relatively close proximity to the Niagara 7000, or only when you place your ear next to the unit, the buzzing is normal and, unfortunately, cannot be eliminated.

What you are experiencing is called magnetostriction. When an extraordinarily high quantity of harmonic distortion is present on an AC line, or when the AC line contains some DC offset voltage that should not be present, even the finest power transformers in the world will react to this problem. In order to reduce or eliminate this distortion, the power transformers try to turn it into heat, causing the transformers’ steel alloy core to hum at 60 cycles per second and all harmonics above that. This has no effect on the performance of the Niagara 7000 or its connected components.

 Ninety-eight percent of installations never exhibit this problem, but that’s no help to the 2% that do. The Niagara 7000 features a very robust DC-blocking circuit that feeds the input or primary to each of the AC isolation transformers, but there are times when otherwise fabulous audio/video component or computer products can nevertheless backwash DC (or a severely chopped waveform) into the output secondary of the transformers. When this occurs, it is necessary to perform some experimentation: Remove each component and its AC cord, one at a time, from the Ultra-Linear Dielectric-Biased Symmetrical Power outlet groups one or two. (The High Current/Power Correction Outlets are in no way connected to these transformers, so these may stay as they are.)

Once magnetostriction is present on a transformer core, the audible noise (saturation) becomes greater as the transformer is asked to pass more current. Moving some products, or a moderately high-current product, to the opposite transformer group may alleviate the problem. Additionally, many computer drives come with external (wall-wart type), switching power supplies that feature chopped AC waveforms. If mechanical noise is present, such power supplies may be better served by the Niagara 7000’s High Current outlets or by using an additional, smaller Niagara Series product, such as the Niagara 5000 or Niagara 500, which does not employ transformers.

If you notice that the slight buzzing sound has increased over time (i.e., was once negligible, but is now quite noticeable), please understand that the Niagara 7000’s AC isolation transformers are like the proverbial “canary in a coal mine.” In all likelihood, the Niagara 7000 has not developed a problem. (If you remove all of the AC output cords and listen for the slight buzzing sounds, you will likely find that they are gone.) However, it is possible that otherwise state-of-the-art components are causing the problem.

 Investigate valve or vacuum tube power supplies. If the tube(s) are wearing, some circuits will offset some DC onto the AC line and back to the Niagara 7000, or affect the AC waveform that the Niagara 7000 feeds. If the components were going into a power filter or conditioner without transformers, you would never be aware of the problem, but transformers never lie: It’s time to replace one (or more) of the power supply tubes!
https://www.audioquest.com/content/pdf/Niagara-7000-Operation-Troubleshooting-Primer.pdf



@ozzy,

"The Niagara 7000 features a very robust DC-blocking circuit that feeds the input or primary to each of the AC isolation transformers,"

That would/should block any DC that might be on the AC mains from reaching the primary winding of the isolation transformers.

.

" but there are times when otherwise fabulous audio/video component or computer products can nevertheless backwash DC (or a severely chopped waveform) into the output secondary of the transformers. When this occurs, it is necessary to perform some experimentation: Remove each component and its AC cord, one at a time, from the Ultra-Linear Dielectric-Biased Symmetrical Power outlet groups one or two. (The High Current/Power Correction Outlets are in no way connected to these transformers, so these may stay as they are.)"

With nothing plugged into the AQ7000 the unit still buzzes loudly, correct?

.

Has the unit always buzzed since you have owned it?
If no, what have you changed?
New IEC inlet connector.
Different input power cord?
New wall outlet?
New branch circuit?
.

Is the AQ7000 AC polarity orientation sensitive?

You can easily check for the correct AC polarity through all the mains wiring through the power cord and out the IEC inlet connector with a multimeter.
Hot to chassis will measure 120Vac nominal. (Any color other that white or gray)
Neutral to chassis, zero Vac. (White wire)
Make sure the neutral and ground wires didn’t get reversed when you changed the IEC connector.
.
ozzy said:
With nothing plugged into the Niagara it still buzzes/ hums but not as loudly and would be tolerable.
The only thing changed is the IEC, and with a polarity tester everything is fine. However, the original IEC was soldered in, the replacement (Furutech is not).

Was that how the unit sounded from day one when you first plugged it in?
Did you contact the seller you bought it from and ask him/her if he/she had a problem with the unit buzzing louder than it normally should?

As for the circuit/polarity tester saying it is correct, fine. I assume that is at the wall outlet. That doesn’t mean it is correct at the end of the power cord IEC female connector. There was a posted message on AA a few years ago where a manufacturer of after market power cords was wiring the IEC connector wrong. He was reversing the neutral and hot wires on the connector. I always check for the correct wiring, polarity, on any aftermarket I use and or buy.
As for the IEC inlet connector you installed. Did you make sure 100% you wired it in correctly? Even a seasoned electrician has been known to miss wire a receptacle putting the hot wire on the neutral terminal and the neutral wire on the hot terminal. That’s why he/she checks to make sure it is correct with a plug in tester.

The reason I mentioned is it possible the AQ7000 is polarity sensitive is because of all the stuff that is packed inside that thing. Just a guess it has all kinds of noise filtering. Hot Line to Neutral Line. Hot line to AC mains equipment chassis ground. And probably even Neutral to equipment ground. The components and wiring designs may be different for Hot to ground filters than neutral to ground filters.


Once magnetostriction is present on a transformer core, the audible noise (saturation) becomes greater as the transformer is asked to pass more current. Moving some products, or a moderately high-current product, to the opposite transformer group may alleviate the problem. Additionally, many computer drives come with external (wall-wart type), switching power supplies that feature chopped AC waveforms. If mechanical noise is present, such power supplies may be better served by the Niagara 7000’s High Current outlets or by using an additional, smaller Niagara Series product, such as the Niagara 5000 or Niagara 500, which does not employ transformers.

If you notice that the slight buzzing sound has increased over time (i.e., was once negligible, but is now quite noticeable), please understand that the Niagara 7000’s AC isolation transformers are like the proverbial “canary in a coal mine.” In all likelihood, the Niagara 7000 has not developed a problem. (If you remove all of the AC output cords and listen for the slight buzzing sounds, you will likely find that they are gone.) However, it is possible that otherwise state-of-the-art components are causing the problem.

Investigate valve or vacuum tube power supplies. If the tube(s) are wearing, some circuits will offset some DC onto the AC line and back to the Niagara 7000, or affect the AC waveform that the Niagara 7000 feeds. If the components were going into a power filter or conditioner without transformers, you would never be aware of the problem, but transformers never lie: It’s time to replace one (or more) of the power supply tubes!
https://www.audioquest.com/content/pdf/Niagara-7000-Operation-Troubleshooting-Primer.pdf

Investigate valve or vacuum tube power supplies. If the tube(s) are wearing, some circuits will offset some DC onto the AC line and back to the Niagara 7000, or affect the AC waveform that the Niagara 7000 feeds. If the components were going into a power filter or conditioner without transformers, you would never be aware of the problem, but transformers never lie: It’s time to replace one (or more) of the power supply tubes!

Never heard of DC passing through the windings of an isolation power transformer. At least not steady state DC. Pulsating DC, yes. Steady state DC, no.

At any rate you need to load the secondary of the unit with a purely resistive load.
Plug a toaster and a coffee maker into it. And anything else you have with a resistive type load. See if the buzz increases with load.
Jim



ozzy said:
I plugged the polarity tester into one of the Niagara outlets and everything showed proper.
If the outlets on the output are fed from an isolation transformer it does not have any electrical connection/reference to the AC Line polarity of the line side, primary, of the transformer.
Secondary polarity is established by the way the secondary winding is intentionally grounded making it an AC Grounded System.
Polarity could be reversed on the primary side and still be correct on the secondary side. Not saying your Line side polarity is reversed though.

Glad to hear you have been able to quiet the thing down. Sounds like a lot of work to me. I hope the improvement it makes to the sound from your audio system was/is worth it.

One thing for sure your thread should be an eye opener for anyone thinking about buying a Niagara 7000. Especially if there is a problem with the unit. Sounds like AQ is not user friendly.
.
ozzy,
Curiosity killed the cat. Did you put the OEM IEC inlet back in the unit before sending it off for service?
Someone please remind me, what is the intended purpose of the AQ Niagara power conditioners?






@axeis1,

Think about it. The unit is suppose to clean up dirty AC mains power. AQ tells the owner if it is buzzing it must be the power in his home is dirty.
Dirty power in the OP’s home? Wait a minute what’s the unit suppose to do again?

Well for the Niagara 7000 to do what it is designed to do it must be fed with clean AC power.

Trouble-Shooting Guide

I hear a slight buzzing sound coming from the Niagara 7000. Is it damaged?

No, it’s not damaged (or, at least, damage is very unlikely). If you’re in an extraordinarily quiet room and you hear this buzzing sound only when in relatively close proximity to the Niagara 7000, or only when you place your ear next to the unit, the buzzing is normal and, unfortunately, cannot be eliminated.

What you are experiencing is called magnetostriction. When an extraordinarily high quantity of harmonic distortion is present on an AC line, or when the AC line contains some DC offset voltage that should not be present, even the finest power transformers in the world will react to this problem. In order to reduce or eliminate this distortion, the power transformers try to turn it into heat, causing the transformers’ steel alloy core to hum at 60 cycles per second and all harmonics above that. This has no effect on the performance of the Niagara 7000 or its connected components.

Ninety-eight percent of installations never exhibit this problem, but that’s no help to the 2% that do. The Niagara 7000 features a very robust DC-blocking circuit that feeds the input or primary to each of the AC isolation transformers, but there are times when otherwise fabulous audio/video component or computer products can nevertheless backwash DC (or a severely chopped waveform) into the output secondary of the transformers. When this occurs, it is necessary to perform some experimentation: Remove each component and its AC cord, one at a time, from the Ultra-Linear Dielectric-Biased Symmetrical Power outlet groups one or two. (The High Current/Power Correction Outlets are in no way connected to these transformers, so these may stay as they are.)

Once magnetostriction is present on a transformer core, the audible noise (saturation) becomes greater as the transformer is asked to pass more current. Moving some products, or a moderately high-current product, to the opposite transformer group may alleviate the problem. Additionally, many computer drives come with external (wall-wart type), switching power supplies that feature chopped AC waveforms. If mechanical noise is present, such power supplies may be better served by the Niagara 7000’s High Current outlets or by using an additional, smaller Niagara Series product, such as the Niagara 5000 or Niagara 500, which does not employ transformers.

If you notice that the slight buzzing sound has increased over time (i.e., was once negligible, but is now quite noticeable), please understand that the Niagara 7000’s AC isolation transformers are like the proverbial “canary in a coal mine.” In all likelihood, the Niagara 7000 has not developed a problem. (If you remove all of the AC output cords and listen for the slight buzzing sounds, you will likely find that they are gone.) However, it is possible that otherwise state-of-the-art components are causing the problem.

Investigate valve or vacuum tube power supplies. If the tube(s) are wearing, some circuits will offset some DC onto the AC line and back to the Niagara 7000, or affect the AC waveform that the Niagara 7000 feeds. If the components were going into a power filter or conditioner without transformers, you would never be aware of the problem, but transformers never lie: It’s time to replace one (or more) of the power supply tubes!
https://www.audioquest.com/content/pdf/Niagara-7000-Operation-Troubleshooting-Primer.pdf

The Niagara 7000 features a very robust DC-blocking circuit that feeds the input or primary to each of the AC isolation transformers,

Not just your run of the mill DC blocking circuit, but a very robust DC blocking circuit!

I am still trying to figure out how a failing power tube in a power amplifier can send DC offset back through the windings of the isolation power transformer of an amp.

Maybe AQ should have put some of them very robust DC blockers on the secondary windings of the toroid transformers in the 7000 to protect them from the equipment the 7000 is supposed to be supplying clean AC power to.

.
@4425,


Rear-Panel Power Correction Switch/Niagara 7000 Current Draw

The default position for this switch should always be “Engaged”—even for applications in which there are no power amplifiers of any kind powered by the Niagara 7000. Defaulting to “Engaged” serves two functions: It activates the Transient Power Correction Circuit for power amplifiers that would be energized by outlet banks 1 or 2, and also provides a portion of the Ultra-Linear Noise-Dissipation Circuit for outlet banks 3 through 6. Although no damage to the Niagara or the connected components will occur, performance will be noticeably compromised when this switch is not set to the “Engaged” position.

However, there is one exception to this. Niagara 7000 has an internal current sense circuit that will automatically engage the Transient Power Correction Circuit, as well as turn it off when your audio/video system is placed in standby mode. To utilize this feature, two things must be present:

1.The primary power amplifier(s) or powered receiver must be connected to High Current/Low-Z Power Correction Bank 1 only (as it is the only power bank with the current sense monitoring for this circuit function).

2.The primary power amplifier(s) or powered receiver must have a power standby mode, and its current consumption at 120VAC in standby mode must not exceed 25 watts. (Although 1 watt is an industry standard for standby power, many great amplifiers routinely dismiss it for reasons of performance over power savings. Therefore, you should consult the specification sheet in your amplifier’s user manual.)

If these two requirements cannot be met, simply place the power correction circuit switch in the “Engaged” position and leave it there! Rest easy, knowing that you will receive every last bit of performance the circuit can deliver. However, if your system allows for the scenario listed above and your amplifier(s) or powered receiver meets the criteria listed above, you may wish to take advantage of the standby circuit. (It is likely that many systems will meet these criteria. However, if the standby function is not important to you, simply leave the switch in the “Engaged” position).

The standby function was not created to place the connected system into a standby or switched mode, but rather to place the Transient Power Correction Circuit into standby mode (disengaged), for instances when the system is powered but not functioning (i.e., when there is no signal present). This was implemented because the Transient Power Correction Circuit creates a reactive current draw of as much as 9 to 10 amps RMS at idle (real world draw is a small fraction of an amp), and electrical technicians who connect a current probe to a product such as this are frequently alarmed: They suspect that the product is either broken or that it is drawing a distressingly high amount of current from the wall outlet (akin to a pair of monoblock power amplifiers left in full operational mode).

This is actually far from the truth. If the Niagara 7000 was consuming that much current (or even 20% of that level), it would need to dissipate the energy loss in heat. It would be quite warm (even hot) to the touch, just like most power amplifiers while in operation. In fact, the Niagara 7000 runs cool, precisely because this current reading is false. The circuit utilizes massive capacitive reactance across the AC line, which, akin to a battery, will both absorb and immediately release the current several times per second. Further, when incorporated with power supplies such as those found in power amplifiers, the current readings actually come down! This is due to what’s known as a vector load, and it’s quite dynamic in an audio system. In this scenario, there is one thing that can run somewhat warmer than it might otherwise: the AC cord that supplies power to the Niagara 7000. This is because the wiring and the circuit breaker that supply power to Niagara 7000 simply look at RMS current and do not distinguish between reactive loads, resistive loads, or inductive loads, but your utility does.

This circuit and many like it have been utilized for many years, and, when tested into buildings with absolutely no loads present aside from the transient power correction circuit, there was virtually zero power draw from the utilities power meter. Still, in an age where so-called “smart meters” are omnipresent, and some utilities may or may not change their standards for “what type of power or current is suitable for billing,” we have gone to great lengths to offer an alternative to those who may be concerned, but who nevertheless wish to achieve the best possible audio or video performance.

Again, if you wish to utilize this feature, and your amplifier(s) and/or powered receiver meet the criteria, simply place the Power Correction Switch in the “Standby” position. Otherwise, please leave the switch in the “Engaged” position.


In fact, the Niagara 7000 runs cool, precisely because this current reading is false. The circuit utilizes massive capacitive reactance across the AC line, which, akin to a battery, will both absorb and immediately release the current several times per second. Further, when incorporated with power supplies such as those found in power amplifiers, the current readings actually come down! This is due to what’s known as a vector load, and it’s quite dynamic in an audio system. In this scenario, there is one thing that can run somewhat warmer than it might otherwise: the AC cord that supplies power to the Niagara 7000. This is because the wiring and the circuit breaker that supply power to Niagara 7000 simply look at RMS current and do not distinguish between reactive loads, resistive loads, or inductive loads, but your utility does.

This circuit and many like it have been utilized for many years, and, when tested into buildings with absolutely no loads present aside from the transient power correction circuit, there was virtually zero power draw from the utilities power meter. Still, in an age where so-called “smart meters” are omnipresent, and some utilities may or may not change their standards for “what type of power or current is suitable for billing,” we have gone to great lengths to offer an alternative to those who may be concerned, but who nevertheless wish to achieve the best possible audio or video performance.

Sure sounds like a leading power factor (PF) to me. A leading PF is just as bad, maybe worse, than a lagging power factor.

It might explain why the "Emotiva DC blocker unit got super hot!"

ozzy OP

3,800 posts
06-04-2019 2:36pm

Well I just received the Emotiva DC blocker and it did nothing. In fact with it plugged into the wall and the Niagara plugged into the Emotiva DC blocker the Emotiva unit got super hot!

So I’m back to square one.

The Audioquest rep says that my Whole House Surge protector (In my Breaker Box) may be the culprit.
Before I get into that, is there any thoughts or opinions on this?

ozzy

A leading PF can not only effect the quality of AC power in your home but also your neighbors that are fed from the same utility power transformer.

https://en.wikipedia.org/wiki/Power_factor

.
@ozzy,
Al, (almarg), would be the guy to talk to. You might want to send him a PM. Ask him if would read your thread.

Jim