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Puritan Audio PSM156 Review (AC Filter)

antcollinet said:
It is very difficult to see how it can be doing any sort of power factor correction - let alone adaptive correction without (as far as I can see) any active power switching devices.

It seems to have (again as far as I can see) only an EMC filter and some transient suppression devices. And given the wire size on that choke, I'd be concerned about its power delivery capability on 4x 1000W outputs. The only proviso is I have no idea what the two cylindrical components marked LAB12 are. I assume capacitors - but who knows.

Most of the circuit seems to be devoted to power analysis - but not much point in doing that if you can't fix anything.

Needless to say - it will provide zero improvement to your audio.
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OK - looking again, what they are calling power factor correction is achieved at the left hand side of the board. I'm guessing it is switching in/out of circuit the two white capacitors using the relays.

I'm expecting they can "adapt" 4 levels of capacitance : none, small, large, small+large.

The problem is that this type of correction is used when driving inductive loads (such as motors), by compensating the inductive phase shift with capacitive phase shift. Further, it is intended to correct the power factor of the system seen by the mains supply, not by the connected devices.

It will do nothing to correct the power factor of typical audio kit power supplies, and in any case power factor correction doesn't help the devices which are generating the power factor issue. So, I'm not seeing any benefit for any connected audio equipment in doing this.
 
Last edited:
pma said:
This thing works quite well and is exactly doing what we expect from the mains filter. The meaningful test would be with several audio components connected to its plugs and mutually interconnected to make an audio chain. Especially if some of them use SMPS power supplies. This would show if there is an effect to reduce switching frequency intermodulations. The test with single component like DAC or preamp is meaningless.
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Hello
I have a device with smps power
Connected on the psm156, we noticed that it was sending noise to the other sockets of the psm!
Measures with an emi line meter
I don’t know if this is normal
 
Papillon said:
Hello
I have a device with smps power
Connected on the psm156, we noticed that it was sending noise to the other sockets of the psm!
Measures with an emi line meter
I don’t know if this is normal
Click to expand...
I would say normal. The device is designed to filter noise from the mains, not from one device to another. Even then it only reduces noise at the higher frequency end by about 10dB

There is a small filter for each socket which will filter some cross contamination - but presumably only provides a small amount of that 10dB.

No filter removes all noise - there is only ever attenuation.


Having said this - it really does't matter. Noise on the mains input to your device is very unlikely (if the device is decently designed) to find its way to the audio output in any audible form.
 
Thanks a lot for your answer.
I am concerned though that the smps power supply then sends noise on the circuit which can't be something beneficial.
but perhaps it's not that important
 
Papillon said:
Thanks a lot for your answer.
I am concerned though that the smps power supply then sends noise on the circuit which can't be something beneficial.
but perhaps it's not that important
Click to expand...
Every** mains powered device emits EMI on the mains - there are even standards that state how much EMI they are allowed to emit, as well as how much EMI a device must tolerate. Typically devices must tolerate 10x the EMI that other devices are allowed to emit.

It really is not that important unless you are experiencing audible noise. Then you need to investigate further - though more often than not, that will be ground loops rather than mains EMI.

** with some few exceptions - eg totally passive devices such as fanless electric bar fires.
 
BlackSpider777 said:
Nice review, so out of all the power conditioners tested in ASR, this is the best from the rest?
Click to expand...
No. Like all power conditioners it does nothing and is a waste of money.
 
Beershaun said:
No. Like all power conditioners it does nothing and is a waste of money.
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This is not quite correct.

They do what they are designed to do - make the mains power cleaner. If this is what they are sold for that is fine.


If they are sold to improve the audio quality out of audio devices - the marketers are lying. Well designed audio devices don't care about power quality - or not the power quality these devices actually improve.
 
antcollinet said:
If they are sold to improve the audio quality out of audio devices - the marketers are lying.
Click to expand...
The marketing and designer are the same people here.
 
The only line conditioner that I have found useful are the ones with a ground lug which makes it easy to have a UL listed way to minimize ground loops. (Panamax). Surprisingly, the very expensive ones don’t include this feature. Series mode overvoltage support and 12V trigger supports have also been features that I have utilized on a “power conditioner” over a plain surge protector.

Otherwise, just like cables, line conditioners, and DACs… No matter what your budget is, dump it into speakers, real estate, or furniture instead of cables/line conditioners/DACs.

I would still run a WiiM mini into a Genelec 8381A than any sort of setup that tried to match the price point or “tier” of the components.
 
antcollinet said:
This is not quite correct.

They do what they are designed to do - make the mains power cleaner. If this is what they are sold for that is fine.


If they are sold to improve the audio quality out of audio devices - the marketers are lying. Well designed audio devices don't care about power quality - or not the power quality these devices actually improve.
Click to expand...
In the context of home audit they provide no value. So I wouldn't characterize it as fine on this forum. If you have a heavy manufacturing forum where dirty mains power has an impact on some use case in that context then it's fine.
 
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Beershaun said:
In the context of home audit they provide no value. So I wouldn't characterize it as fine on this forum.
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And given that. for this brand, they do sell heavily on audio performance - I would 100% agree.
 
“Definition takes an enormous stride forward, individual instruments gain air between them with their sound and timbre becoming believable, the sound-stage will move out of your speakers and into the room with gains in three dimensionality with clarity definition and space between the instruments for them to interrelate rather than muddle each other. Your listening will become a far more engaging and pleasurable experience.“

It is so frustrating that the Puritan PSM136 might be cleaning my mains supply to my hifi system but that its not doing anything for me as described above on their website.

While it might be true that I am not getting any clicks or pops with it in place that is not the benefit that the company claims.

Another frustration is that they have prominent stands (in a tight busy corridor at Bristol Show) at several big hifi shows in the UK and are no doubt doing very well in sales using their unverifiable hype.

A final frustration is that many consumer reviews are positively glowing about their purchases (and almost certainly genuinely so), while my one negative review was not accepted for publication on a very reputable dealers website (maybe many others too?).
 
Trondi said:
“Definition takes an enormous stride forward, individual instruments gain air between them with their sound and timbre becoming believable, the sound-stage will move out of your speakers and into the room with gains in three dimensionality with clarity definition and space between the instruments for them to interrelate rather than muddle each other. Your listening will become a far more engaging and pleasurable experience.“

It is so frustrating that the Puritan PSM136 might be cleaning my mains supply to my hifi system but that its not doing anything for me as described above on their website.

While it might be true that I am not getting any clicks or pops with it in place that is not the benefit that the company claims.

Another frustration is that they have prominent stands (in a tight busy corridor at Bristol Show) at several big hifi shows in the UK and are no doubt doing very well in sales using their unverifiable hype.

A final frustration is that many consumer reviews are positively glowing about their purchases (and almost certainly genuinely so), while my one negative review was not accepted for publication on a very reputable dealers website (maybe many others too?).
Click to expand...
Interesting, you got the PSM136 since howlong? Could you share what is attached to it?
 
BlackSpider777 said:
Interesting, you got the PSM136 since howlong? Could you share what is attached to it?
Click to expand...
Hi BS. I have been using it for 3 years or so, mainly because it might be doing some protection for household clicks and pops. It outputs to my TV, NAD amplifier, sonos gear and Oppo disc player.

I would have sold it were it not for the fact that it does not do its advertised functions for SQ.
 
Trondi said:
Hi BS. I have been using it for 3 years or so, mainly because it might be doing some protection for household clicks and pops. It outputs to my TV, NAD amplifier, sonos gear and Oppo disc player.

I would have sold it were it not for the fact that it does not do its advertised functions for SQ.
Click to expand...
No Offence but for your gear, you could have just bought a power strip with surge protection. Is it a NAD Master series? which speakers?
 
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