AudioQuest PowerQuest 3 Power Conditioner & Surge Protector Review

[solderdude]

Yes that looks like great software. I see in that thread I linked to he incorporated Serge's Df metric into DeltaWave after a discussion on how to calibrate their algorithms to match. I believe Serge's is still more accurate as it finds a single global minimum when iterating over time shifts to eliminate drift, but it seems DW's computation is faster, if less accurate.

Serge's software also provides 'similarity space' plots, plotting devices with a similar distortion profile when playing real music closer together in a 3D graph, which is very interesting. For example, it plots the ~$1000(!) iBasso DX220 quite close to the $9 Apple dongle in similarity space:

As well as giving them a very similar Df value of -29.6 and -29.1 dB respectively when playing real music (the similar distortion profile can also be seen from the very similar Df histogram shape):

This is despite the fact the DX220 measures significantly better in the sine tests, which is supported by your measurements of the Apple dongle and the DX200 (assuming the latter is similarly performing to the DX220), demonstrating a SINAD difference of 9 dB, as well as showing they have different THD profiles:

Serge talks about such differences in standard synthetic test measurements yet similarity when playing real music (what he calls the 'm-signal') here:


Obviously order of harmonic distortion does matter in terms of audibility/objectionability (odd>even, higher>lower) as research shows, so individual THD tests are still useful for a finer grained judgement of sound quality, but it seems the Df metric (calculated using either Serge's or the DeltaWave software) would be a better measure of overall transparency and so sound quality than SINAD, seeing as it reveals the actual level and profile of distortion when playing the real music we use the DUTs to listen to, as opposed to just artificial test tones.

Funny how the $2500 Chord Hugo competes with the $100 DAP M0.
M0 = 8mW in 300 Ohm where the Hugo2 is 94mW in 300 Ohm.
Below 8mW this and all other DAPs will be indistinguishable from each other.

One can start to wonder how useful this test really is.

 

[Swtoby]

If a whole house solution isn't an option, what are some surge protectors that are recommended? I find the opinions around the internet confusing. Some say the component's power supply should be ok outside a lightening strike others whole house or bust. I usually run around unplugging everything from the wall during storms, but I'm not always home to do that.

 

[amirm]

I don't recommend any "point of use" ones. Better to make sure your homeowner insurance covers such things (most do). If a real lightning comes, none of these would do a thing. It is like trying to stop a train by just standing in front of it.

If you own your home by the way, call the electric company and they will install one at your meter. It is the best place to put it for external surges because it has the shortest and best path to the ground. They open the meter, put in the module and close it back up. I think we paid $300 for ours, installed.

 

[GXAlan]

I don't recommend any "point of use" ones. Better to make sure your homeowner insurance covers such things (most do). If a real lightning comes, none of these would do a thing. It is like trying to stop a train by just standing in front of it.

If you own your home by the way, call the electric company and they will install one at your meter. It is the best place to put it for external surges because it has the shortest and best path to the ground. They open the meter, put in the module and close it back up. I think we paid $300 for ours, installed.

Next step: Audiophile-grade solar panels or inverters and AFCI components.

 

[Labjr]

I just unplug electronic equipment during thunderstorms or if I'm not going to be using it for a while, going out of town etc.

 

[amira]

I don't recommend any "point of use" ones. Better to make sure your homeowner insurance covers such things (most do). If a real lightning comes, none of these would do a thing. It is like trying to stop a train by just standing in front of it.

If you own your home by the way, call the electric company and they will install one at your meter. It is the best place to put it for external surges because it has the shortest and best path to the ground. They open the meter, put in the module and close it back up. I think we paid $300 for ours, installed.

I don't see it as an either-or proposition. As with most things safety or security related, layers are better than depending on a single device or method for safety or protection. I'm really glad they were added to the NEC. I installed an Eaton whole home surge protector at my panel 7 years ago. Since then, I've still had devices fry with blown MOVs.

IIRC, the whole home units all let through at least ~600V. So point of use surge protectors can be useful, especially if they have over-voltage disconnect circuits. I think that's probably the most important feature and I don't use any of them without it.

Of course, nothing offers protection from a direct lighting strike. I'm just looking to protect my house and devices from lightning strikes and surges further upstream. Not to mention loose wires in the panel, downed power lines, issues at the plant, etc.

Insurance is great for catastrophic events, but you have to meet the deductible (almost $4k in my case) and it will raise your future rates.

 

[ernestcarl]

Interesting!


It would be interesting if you put a vacuum cleaner on an isolation transformer or your led lights on an active line conditioner how it would work. Do you have problems when running the microwave? Both the vacuum and laser printer are high current devices.

The LED lights are ceiling lights and not those ones plugged into an outlet.

Not sure if an isobar ultra fits the category you had in mind (I don’t specifically own an audio/electronics conditioner) but the laser printer is plugged in one of those expensive isobars, and it still affects the lights above — but only when starting up. After the initial flicker, everything becomes stable even while still printing more pages. I do have two of this: https://www.cyberpowersystems.com/product/ups/pfc-sinewave/cp1350pfclcd/

I don’t think it makes any sense to plug a vacuum cleaner regularly in one of its outlets though as the current draw is pretty high (12 amps) — definitely not at the same time as other electronics are plugged already into it and running. I use it mainly for stuff that need to run 24/7 like a NAS, routers, or my server PC... I would have to lug it upstairs and attach it to that specific outlet. Maybe next time... I haven’t shut off the NAS or server PC in months — or maybe that was last year.

 

[bobbooo]

Funny how the $2500 Chord Hugo competes with the $100 DAP M0.
M0 = 8mW in 300 Ohm where the Hugo2 is 94mW in 300 Ohm.
Below 8mW this and all other DAPs will be indistinguishable from each other.

One can start to wonder how useful this test really is.

It's useful in exactly the same way as the SINAD metric, except moreso as it measures all possible degradations of the input signal, rather than just noise and THD. Like SINAD, the Df value is purely a measure of transparency, in particular total DA(D) conversion error. Of course other considerations such as output power, impedance etc. need to be taken into account depending on the use case of the DUT, so Df values can be compared within a particular use case, just as SINAD currently is.

Also like SINAD, Df is limited by the amount of noise and distortion inherent in the AD conversion of the recording device used to measure it. This means the Df values of DUTs near the top of SoundExpert's list may be underestimated.

The particular devices you're referring to were measured using the RME Babyface Pro, which from this page of loopback measurements has a Df ~ -35 dB, around the same as that of the Chord Hugo 2 and Shanling M0's measured values, which suggests these devices were reaching the limit of the Babyface Pro's measuring ability and either or both their true Df values may be better (lower). Measurements on that same page above of the LG V30 smartphone show a Df of -43 dB, identical to the loopback Df of the MOTU 828 MkII used to measure it, suggesting this value is also measurement-limited and may in fact be even better. Incidentally, the Shanling M0 shares the same ESS Sabre ES9218P audio chip as the LG V30, which is further evidence the former's actual Df was underestimated in the measurements, so may be as good (or better) than the V30's measured -43 dB value. Just like for SINAD, Df measurements require high quality equipment, such as Amir's, with less noise and distortion than the DUT's in order to produce precise and reliable measurements of the latter.

 

[Head_Unit]

line conditioner...almost $10K...Compare...to a Bugatti...or even a Rolex...brings some artistry/craftsmanship to the pride of ownership and is able to provide measurably superiority[impressive water resistance].

And the Bugatti is likely to appreciate in value, and the Rolex hold or increase. The BEST water resistance, strapped to the bottom of the Trieste in 1960 and James Cameron's Deepsea Challenger in 2012. (Omega now edged them out it seems https://www.qpmagazine.com/watch-cu...-ultra-deep-professional-record-deepest-dive/
No word who provided the power filtering for any of these dives
As for the concept, yeah I've always felt "shouldn't the device have enough filtering?" though a Monster unit I got more for just distribution did result in a clearer picture on the rear projection TV I had at the time-even my wife noticed that. Our AC sucked at the time, and maybe there was some synergistic isolation effect? Who knows.

 

[amirm]

I don't see it as an either-or proposition. As with most things safety or security related, layers are better than depending on a single device or method for safety or protection. I'm really glad they were added to the NEC. I installed an Eaton whole home surge protector at my panel 7 years ago. Since then, I've still had devices fry with blown MOVs.

The Eatons aren't very good. They don't have any fusing and blow up themselves:

IIRC, the whole home units all let through at least ~600V.

Your unit is probably installed too far from the grounding bar in the panel if it is letting through that much voltage:

This is why I recommended SPDs that fit inside the meter. It has the lowest impedance there and hence lowest let-through voltage.

 

[solderdude]

It's useful in exactly the same way as the SINAD metric, except moreso as it measures all possible degradations of the input signal

I am very familiar with (analog) nulling. The biggest snag is that small phase shifts, which are inaudible, are also converted to errors and are difficult (but not impossible) to remove from the null.
So this means that the metric has some issues that need to be removed or weighed and explained.

I know Archimago also experimented with nulls and seemed to get much deeper nulls by selecting only short moments where due to shifts in sample speeds the null was the most perfect. I know pkane and serge were also discussing this along the way.
This needs to be resolved before I would want to use this metric and also would like to see ADC's used that do not add to the metric.

The was to design a metric that jived better with perceived SQ. I am not seeing this yet. Nor is SINAD an indication of SQ. Nor will there ever be a metric that will have a relation with perceived SQ because of the brain being a very poor measurement device when used in conjunction with other senses.

I applaud the efforts but like to see a better implementation.

 

[scooter]

I just unplug electronic equipment during thunderstorms or if I'm not going to be using it for a while, going out of town etc.

Same here. My home power network is equipped with breakers only on hot ones, neutral is grounded near a house and wired directly to each receptacle. So only way of protection is to unplug the connected electronics.

 

[paddycrow]

I have to admit that I have a power conditioner in my system, but my observation has been that it has zero effect on sound. It does make a nice power distribution box. (Fortunately, I didn't pay retail.)

 

[bobbooo]

I am very familiar with (analog) nulling. The biggest snag is that small phase shifts, which are inaudible, are also converted to errors and are difficult (but not impossible) to remove from the null.
So this means that the metric has some issues that need to be removed or weighed and explained.

I know Archimago also experimented with nulls and seemed to get much deeper nulls by selecting only short moments where due to shifts in sample speeds the null was the most perfect. I know pkane and serge were also discussing this along the way.
This needs to be resolved before I would want to use this metric and also would like to see ADC's used that do not add to the metric.

The was to design a metric that jived better with perceived SQ. I am not seeing this yet. Nor is SINAD an indication of SQ. Nor will there ever be a metric that will have a relation with perceived SQ because of the brain being a very poor measurement device when used in conjunction with other senses.

I applaud the efforts but like to see a better implementation.

I already mentioned these issues earlier in this thread. Serge's software includes an algorithm which finds the global minimum Df value for any input/output pair by iterating over all possible phase/time shifts, up to arbitrary accuracy (currently 0.0001 dB), only limited by how much processing power and time you have. So this isn't really a problem anymore. DeltaWave attempts to adjust for phase/time shifts as well, albeit with less accuracy, but faster.

Serge is also attempting to quantify the correlation between null difference measurements and listening tests, which has shown some promising results. I'm not aware of any equivalent evidence for the correlation between SINAD and listening tests.

Having said that, I think Serge's aim with the Df metric is to push manufacturers to improve their products' performance to a threshold point where Df errors are provably inaudible, just as Amir's SINAD measurements are doing for THD and noise, which have been given a strict inaudibility limit of -120 dBFS. Serge says data suggests the limit for Df inaudibility could be around -50 dB. At that point you won't need to worry about the subjective psychoacoustics of perceived sound quality; it's just an objective engineering matter of reducing signal degradation in the DA/AD conversion chain to a provably inaudible level.

Sound quality is then purely left up to the music recording/mixing/mastering process at the input end, and sound preference is optionally left up to EQ/DSP at the output, as it should be (and arguably transducers, but I'd say they should be 'lossless' too i.e. as close to the transducers used to master the music as possible, just like the standards and calibration of consumer TVs attempt to match film mastering monitors/screens, preserving the artist's intent). Everything in between should just be audibly lossless DA/AD conversions. Psychoacoustics is not needed for any part of an audibly lossless audio conversion chain (e.g. take FLAC compression as a trivial example).

And yes, as I said, the AD converter used to take the Df measurements needs to have lower signal degradation than the DUTs in order to produce accurate and reliable data (not 'add to the metric' as you say), as is the case for SINAD. The beauty of the Df metric and it's open source software (or its implementation in DeltaWave) though is anyone can calculate it for any device, as long as they have high quality ADC equipment such as Amir's, just by recording its output of real music.

 

[amira]

The Eatons aren't very good. They don't have any fusing and blow up themselves:

View attachment 72630

View attachment 72631


Your unit is probably installed too far from the grounding bar in the panel if it is letting through that much voltage:

View attachment 72632
This is why I recommended SPDs that fit inside the meter. It has the lowest impedance there and hence lowest let-through voltage.

I followed the instruction recommendations and kept the wires <12" with several twists. So I should be getting the specified VPR of 600V. The panel is also right next to to the grounding rod.

Personally, I wouldn't ever put a device jam packed with MOVs inside any enclosure with things like wires that can be damaged by heat. MOVs tend to do their job in a rather violent manner, so allowing it free space is a good thing. Mounting it on the outside of a panel also allows you to quickly see the protection status LEDs.

All the Type 1/2 SPDs I found have a VPR of 600V or higher. So according to that chart, one should expect the possibility of an additional 60V in the best case. That's why I said point of use surge protectors are not rendered unnecessary by a Type 1/2 SPD. The ones that I use have been independently measured to only let through 90V from a 5000V surge. So they could handle any surge that gets passed the panel.

Not sure of the model you posted, but this is the Eaton unit I was referring too. I don't doubt that it would meet a violent end when dealing with a catastrophic surge, in fact I've planned for it.

What brand do you recommend?

 

[snake3276120]

APC power bar is all you need

 

[amira]

Not to tangent this thread too far, this is from the IEEE guide for surge protection:

"One of the main functions of the service entrance SPD is to reduce the surge current reaching any downstream protectors (see requirement 2 under Section “2.2 Surge Protective Device Ratings” on page 15 of this Guide). For this use, the surge limiting voltage is not critical. But for requirement 1 (in Section 2.2), protection of hard-wired equipment, a low let-through voltage might be important. Selection of a service entrance protector may require a compromise between emphasizing a lower limiting voltage rating (best protection for the hard-wired appliances) versus choosing a higher voltage rating SPD that may be less vulnerable to temporary AC overvoltages.

Two-stage protection, where an upstream SPD takes the major surge current and a downstream SPD protects the equipment, is the best protection for equipment. Unless the downstream SPD is very close to the upstream SPD, the surge limiting voltage of the upstream device will have little impact on the final voltage seen by the load after the second SPD has limited the surge remaining from the first SPD.

As stated above, the service entrance SPD has the primary job of intercepting large incoming surges and disposing of them into the building ground. However, some of the surge will be conducted downstream to the appliances in the building, and to other SPDs, either hard-wired or plug-in protectors."

http://lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf

 

[GXAlan]

My JBL SA600 integrated amplifier has a test switch that does a real-time difference between the two channels. With a monophonic source, you should get no output from the speakers if they're perfectly matched. With an optical splitter, you could compare two DACs with different power supplies, etc. that way. They make ABX boxes -- maybe it's trivial to make a comparator-box.

 

[pozz]

I already mentioned these issues earlier in this thread. Serge's software includes an algorithm which finds the global minimum Df value for any input/output pair by iterating over all possible phase/time shifts, up to arbitrary accuracy (currently 0.0001 dB), only limited by how much processing power and time you have. So this isn't really a problem anymore. DeltaWave attempts to adjust for phase/time shifts as well, albeit with less accuracy, but faster.

Serge is also attempting to quantify the correlation between null difference measurements and listening tests, which has shown some promising results. I'm not aware of any equivalent evidence for the correlation between SINAD and listening tests.

Having said that, I think Serge's aim with the Df metric is to push manufacturers to improve their products' performance to a threshold point where Df errors are provably inaudible, just as Amir's SINAD measurements are doing for THD and noise, which have a strict inaudibility limit of -120 dBFS. Serge says data suggests the limit for Df inaudibility could be around -50 dB. At that point you won't need to worry about the subjective psychoacoustics of perceived sound quality; it's just an objective engineering matter of reducing signal degradation in the DA/AD conversion chain to a provably inaudible level.

Sound quality is then purely left up to the music recording/mixing/mastering process at the input end, and sound preference is optionally left up to EQ/DSP at the output, as it should be (and arguably transducers, but I'd say they should be 'lossless' too i.e. as close to the transducers used to master the music as possible, just like the standards and calibration of consumer TVs attempt to match film mastering monitors/screens, preserving the artist's intent). Everything in between should just be audibly lossless DA/AD conversions. Psychoacoustics is not needed for any part of an audibly lossless audio conversion chain (e.g. take FLAC compression as a trivial example).

And yes, as I said, the AD converter used to take the Df measurements needs to have lower signal degradation than the DUTs (such as Amir's equipment) in order to produce accurate and reliable data (not 'add to the metric' as you say), as is the case for SINAD. The beauty of the Df metric and it's open source software (or its implementation in DeltaWave) though is anyone can calculate it for any device, as long as they have high quality AD equipment, just by recording its output of real music.

You should check out Serge's very long discussion regarding this approach with @j_j and others across multiple threads. A lot of it was beyond me. What I came away with was that it does not present a valid replacement for traditional testing, the issue being the psychoacoustic aspect. Serge seemed uninformed regarding established use of dither and perceptual audio coding in terms of assessing signals for their audible qualities (important since the signal assessment is his main point rather than measurement).

If you want to keep the discussion going, do you mind starting a new thread?

From what I remember @pkane added df calculation to the null software. I'm also not sure how much nulling accounts for run-to-run measurement variations. You can look up pkane's older attempts (before Serge joined ASR) to measure and compare cable differences in the review index.

 

[MZKM]

You have ruffled the feathers of Mr. Rubinson‘s coworker: