Puritan Audio PSM 156 Power Purifier Review.
By Steve Huff
My power story from the Niagara 1200/3000, PS Audio P20 and Puritan 156.
I have learned more than ever this year that the power coming into the your home that feeds your audio system is just as important as the speakers and the amp we choose. I used to be a “Power Denier” thinking that fancy power conditioners and cables were for suckers. I have been slowly coming around after all of this time, and especially after trying for two years to solve my power issues in my listening room.
Even though I live way out in the woods in complete privacy on 20 acres of land our electricity is still polluted with “something” that makes my system sound awful at various hours of the day. Without any power solution in place my system can be downright nasty at times, and unlistenable. Yes, even though I have a system that has a retail value of $65k it sounds flat, harsh and without involvement without a power solution in place due to the quality of the electricity coming into our home. That alone is proof enough for me that power conditioners do work, for people like me with nasty power.
For the last year or so the solution for my system was in the form of the $10,000 PS Audio P20. Yes, I went for teh big guns when nothing else worked to my satisfaction. While that P20 solved 90% of my issues, it did not solve 100% of them. After getting my room rewired by an electrician I sold the P20 to cover the funds for the re-wire. Pr0blem is the re-wire did not solve anything at all and I ended up without a solution and a system that was very bi-polar. One day it was gorgeous, next day it was flat, sterile and hard sounding.
It really sucks when we spend all of the money building a system that sounds to our liking and then one day it just falls flat and sound had, broken and off.
This is a phenomenon within HiFi for many of us who listen to our systems with a critical ear. Some feel it is our own moods that cause this and others say it is the quality of our POWER causing this issue.
I now know 100% that it is the POWER without question as the Puritan solved all of these issues for me, finally.
Over the last 2+ years I have battled noise issues with the power coming in from the wall into my HiFi Gear and it took me that long to find a 100% rock solid solution to the issues. I thought I had the issues fixed when I splurged for that PS audio P20, which is a power plant that regenerates all new electricity for your system. The P20 regulates voltage and supposedly eliminates all DC from the line as well (I do not feel it eliminates all DC).
When I started noticing the P20 humming from teh power I was feeding it from my home I knew there was something seriously wrong! I took the P20 to my mothers house an hour away and there it was silent as a mouse when plugged in but here, something was causing it to hum at times. It is after all an AMP itself with a giant toroidal transformer so if amps are buzzing it would make sense that whatever was causing the issue, it was causing the issue with the P20 itself.
The HUM and BUZZ
Have you ever had an amp that had a hum or buzzing coming from it while on? That is usually transformer buzzing and it is annoying as can be when you turn on an amp and hear it. It usually stems from having DC on your power lines and yes, this is a thing. Sometimes we hear the hum or buzz up close, other times we hear it at our listening seat. It can be minor or it can be LOUD.
I have had a few amps come through here in 2022 that had a buzzing coming from the transformer. I assumed they were faulty so sent them back without review. Not all amps would buzz in here, but some did. It seemed odd and random and I could not figure out if it was truly the amplifiers or still issues with my power lines.
When I noticed a buzzing coming from my brand new Luxman 595 ASE I knew something had to be off with my power (with P20 Installed) as this brand new special piece from Luxman surely could not have a defective transformer?
I decided to have my room re-wired completely. Some of the old work was sloppy so having it redone would maybe fix some of the pollution issues, at least that was my thought. After spending a few grand doing this I removed the PS Audio PP20 from the system, thinking I could sell it to recoup the costs of what I just spent on the re-wire.
Well, I removed the PP20 after the re-wire job and the system sounded much different though I admit, I did a very quick audition. It was more lively, less warm. It had more details jetting out and was not as mellow. Hmmm, I liked this new sound (or so I thought) so I listed and sold my PP20 to recoup the funds that I spent on the re-wire. It sold within a couple of days. As luck would have it, the day after I shipped the P20 to the new owner I noticed my system sounding dead, flat, hard and way off.
It was too sharp, had no depth and no life. It was no longer sucking me into the music. The imaging was off, the sound was just not good. I brought in a Nordost QB8 power block I had on hand (which is not a conditioner or purifier, rather a nice distribution block that passively cleans up the power). That did not help with my issues or the sound variations at all.
All of the sudden I was noticing a louder buzz coming from my 595 ASE. I mean, this was as loud as I have heard it and I slightly heard it at my listening seat. Hmmm. Over the next few days I noticed as the buzzing went from loud to soft to loud again, depending on time of day. This also effected the sound and not for the better.
I was very bummed that I sold my big P20 as it was truly making the system sound glorious 24/7, no matter when I turned it on though it didn’t solve the hum issues. I guess thinking a rewire would help was silly, as it made things worse it seems with a much harsher sound on most days. The treble sounded ragged and even listening with Debby three nights in a row, without saying a thing about it to her, she said “why does it sound so flat tonight” and “it’s not sucking me into it tonight”. Yes, she heard the change easily.
I told her I removed the P20 and sold it, which she knew about but she doesn’t really know about hardcore specifics of what products do what. She was shocked at the change in sound. As we sat and listened we were both wondering how this could be fixed. I was listening and thinking that this system sounded horrible and was no longer fun to listen to. It was crazy, whacky and I even thought for a moment something happened to my Lina DAC or even the 595 itself.
I reset the DAC, unplugged the amp and then plugged it back in. No change. Still hard, flat and sounding very off.
Then I remembered a recent visit to Glenn Poors Audio in Champaign, IL. I am a big believer in “signs” and I pay attention when something is presented to me in life when it makes sense to a current situation in my life. While at the shop the owner was telling me, with excitement, about a power purifier he sells (along with two other brands he sells) that was head and shoulders above the rest. Like nothing he had ever heard, regardless of price.
I didn’t even ask him about power products, he just decided to tell me about it.
That purifier was the Puritan Audio PSM 156 with their Ultimate Power Cable. It was a basic looking black box with 6 outlets and it did come with the best power cable Puritan makes, which intrigued me as it was gorgeous and FLOPPY. I have never seen a power cable like this. As I was being told just how amazing this product is at removing all DC from the power line while also removing noise and crud, I was very skeptical.
The literature for the PSM156 states it will keep amps from buzzing as one of its feature sets by eliminating DC from you line. I have heard that before though as I tested cheap DC blockers that did nothing at all. I was very skeptical as always.
I have had conditioners from Audioquest here, the Niagara 1200 and 3000. I have had the mother of all regenerators here, the PS Audio P20. I once had a Thor conditioner as well as a nice $5k range Isotek. They all did something to the sound. The Audioquest added more shine and excitement, the P20 added richness, soundstage width and warmth. The Isotek seemed to do the least. The P20 did solve some of the hum issues but on some days the hum would still come through.
No matter what I used though, it never eliminated the buzzing from all amps that traveled through my doors. I even bought an Isotek Syncro which was supposed to remove DC from the line. Problem is the Syncro only seems to remove some of the DC, so it reduced the hum and buzzing of the 595 ASE but did not eliminate it. I tried the Emotiva $100 DC blocker and that did nothing at all. Not even a hint of removing the hum.
When a transformer is under stress from DC it vibrates, loosens up and starts to create a buzzing sound. When this happens that transformer is not performing at its best and therefore it seems it can even possibly alter the sound of your system, unless it is the other crud on the line doing these things to the sound.
When there is noise, grit and grunge on the line, this also effects the sound of your system. It may sound bleached, hard/harsh and/or just off. No depth, imaging suffers and we may even get smearing of the sound.
Not everyone has power issues but for those of us who do it can be very frustrating.
The signs of bad power are usually a system that sounds amazing one day and like junk the next. It may sound sublime at 6AM and awful at 5PM. That is not your ears my friends, it is your power messing with your system. You may notice it going from expansive, rich and with nice bass to flat, sterile and lacking in bass. I used to think it was my ears back when I was a “power denier” but today know 100% that it is based on the power coming into my home.
I know this as I went back to Glenn Poors Audio and bought that PSM 156 with the Ultimate PC. I was told if it did not do what it claimed to do I could return it within a week for a full refund. I bought it, took it home and set it up in my system. I truly expected it to not do a thing and I told them that at the shop. I wanted them to expect it to be returned.
I was told no one has ever brought one back, ever. Hmmm. Sales pitch or is there really something to this little black box that can do what no other power product has done for my system?
When the PSM156 was installed and I fired up The Luxman 595 ASE the first thing I noticed was it was 100% dead silent. No buzz, no hum. AT ALL! Even with the P20 there was a slight buzzing that started coming from the 595 and into the wall direct there was a loud buzzing from the transformer of the 595. Going to the wall was not an option for me here as it sounded the worst without question.
With the Puritan 156 and Ultimate PC installed and feeding all of my audio components including the amp, the buzz was 100% eliminated. The next thing I noticed was the complete lack of hiss or noise from the speakers. There was a blackness there that was deeper than it was with the 3X more expensive P20. I have never heard my system sound the noise free. It was pretty remarkable at how this changed the sound as I was now hearing everything layered on what was like a massive black hole in my listening space.
When I fired up the music the hardness was 100% gone. The edginess was 100% gone. The bass was back (this was dramatic) as was the richness, the beauty and holographic soundstage. Everything came back, and I swear it is even better than it was with the P20. I do think the P20 is a better unit overall as it also regulates voltage and in my system sounded more refined and smooth vs the Puritan. Even so, I was hearing more details and layering with the Puritan, while it stayed full and with body to the music.
Debby came in to listen and as she did a huge smile appeared on her face, she got up and started to dance in the room. “It’s back” she proclaimed and she was right. The MAGIC was back but it was better than before.
To make sure it wasn’t a fluke or time of day coincidence I removed the PSM 156 again and went to the wall/power strip. The buzz was back, the hardness was back and the sound was just awful. I mean, a complete 180 and it wasn’t subtle at all. The 156 was placed back in the system and the magic came back. The silence was back. The sweetness and richness of the sound was back as was the immense large scale of sound.
This difference was quite dramatic as in NIGHT and DAY kind of stuff so yes, it was indeed my power. Not my “mood” on any given day : )
We sat there in disbelief that this little black box was doing all of this. It was indeed the power and it seemed like I wasted my money getting new wiring as that wasn’t the issue at all. For me, the main issue seems to be that there is DC on the line. This is possibly what was killing my sound and even causing some hum and buzz within my system components.
I have had conditioners in here ranging from $1k to $10k and this little box with its unique floppy but superbly made power cord comes in at $3300 retail with the upgraded ultimate power cord. That may sound expensive for what looks like a glorified power strip but this thing is far from being a power strip.
I also highly recommend going the ultimate route here as what it did for my system was almost unbelievable. I still do not understand it but holy wow, this thing is one of those products within HiFi that delivers on its promise. It states that it will stop noise, buzzing and hums from transformers and it did, 100%. It states it will clean your power which will bring forth a blacker background and the absence of grit and noise. It did this 100% better than any other conditioner I have heard.
This PSM 156 does not suck out dynamics and with my amp plugged right in there are no issues as this will not limit current. It’s truly the perfect power product for any nice system no matter the cost of your system. Again, this does not limit current and your amp will most likely sound better plugged into the Puritan.
It’s so good I dream of one day replacing all of my power cables with the Puritan Utimate cables. As it sits now the PSM 156 is one of the best audio buys I have ever made for my system, ever. There is no need to spend more for setting up the foundation of a system, the Power.
Even if you think you do not have power issues ask yourself if your system sounds different to you on different days. Does it sound amazing on some nights yet falls flat on some other days or nights? Does your system sound hard, compressed or bright? Is it flat without depth and a rich deep soundstage? Is it lacking bass in the mids and bottom? These variations can come and go, be there one day and gone the next.
If you yelled out “yes” for any of these questions you may have a power issue which is keeping you from hearing what your system COULD sound like. My guess is that if you auditioned the PSM156 those issues would improve or go away all together. The good thing is that most dealers who carry the PSM 156 will let you audition it or try it out in your own system.
If you have a dealer near you run to that dealer now and ask about testing one of these out. You may find that like me, it is a mandatory product that truly helps the music flow without those nasty power gremlins degrading your systems potential. For me it is just as important as the speakers, amp and DAC.
Where the P20 made me a 100% believer in power products the PSM 156 made me a 110% believer in power products. While I loved the PS Audio PP20 for its voltage regulation I feel it did not remove all DC from my line (or it was possibly removing it but creating small amounts of DC and injecting it back in). I am not sure as it reduced the transformer buzz in the affected amps by 90%. The Puritan removes 100% of the noise as well as eliminates all noise and hiss that was coming from the speakers. It does this for almost $7k less money than the big 105lb P20.
That is a big deal for me as I have been trying to get this solved for TWO YEARS!
While this PSM 156 may not be a cure for all, if you have power issues I feel there is no better power purifier on the market, at least that I have heard. I have read forums and some have replaced their Shunyata, PS Audio, Niagara and higher end conditioners for the PSM 156. Some have replaced their fancy $5-6k power cables with the $800 Ultimate. There are many happy owners of the PSM and I am now one of them. It’s probably why you rarely see them on the used market as well. They do their job very well.
My system sounds its best 24/7 now and there are no shifts in the sound quality, much like what the $7k more expensive P20 did.
For me, compared to going in to a standard power strip the PSM 156 w/Ultimate PC made these improvements to the sound:
- Wider soundstage. More air. Hidden details appear from silence.
- Richer sound, bass is back down low and in the mids. Much fuller.
- Extreme clarity but with body and beef.
- Reverb trails within the recording can be easily heard, voices float.
- Much larger “wall of sound” fills the room.
- All edginess is gone.
- All noise is gone.
- Much more musical and effortless.
- All of the flatness vanished, now sound is dimensional (unless an awful recording is played of course)
- Sounds like this 24/7 and doesn’t change.
Compared to the PS Audio P20:
- The Puritan is cleaner and clearer sounding with more treble extension.
- The P20 regulated my high voltage, the Puritan does not.
- The P20 still had my Luxman 595 emitting a slight hum from the transformer (didn’t get all DC from my line)
- The P20 had my system sounding warmer, a little richer. Was beautiful, but the Puritan is more “alive”. Take your pick. Both allow the system to sound glorious 24/7 without sound shifts.
- The Puritan is $3300 with ultimate power cord included. The P20 is $10k with a basic $7 cord included.
- The P20 creates all new “grunge free” electricity for your system, the Puritan purifies what you already have.
- The Puritan is much smaller, lighter than the mighty impressive 105lb P20.
Compared to the Audioquest Niagara 1200/3000
- The Niagara line sounds more lit up in the top end and in my system made the mids leaner vs the Puritan.
- The Niagara is nicer looking in design.
- The Puritan creates a blacker background, I mean, as black as it gets.
- The Audioquest does not remove DC from your line.
- The Puritan sounds bigger, richer, and well, better to these ears vs either AQ piece.
I have never heard a power product like the Puritan PSM 156 with the Ultimate PC. It’s almost like a new set of speakers or amp was put into the system. That is not hyperbole in any way but remember, my power is not the greatest and this product is for those of you like me who have these issues. If you do not have power issues this may do nothing for you at all.
Again, if you find your system sounds different from one day to the next, or if you have buzzing transformers or if you feel your system is just not involving then you may just have power issues that you may not even be aware of.
An audition of the PSM156 will show you if it is your power as if it is, it will fix it.
For me, this is the only power product I will recommend from this point on (at any price point) unless something bests the Puritan for less. I have never found a product like this that performs above its price point to do everything it claims to do, perfectly. I have $3300 less in my pocket today but I have never been happier to spend $3300. The PSM 156 is the real deal and it is the product I have been searching for all along.
The 156 has 6 outlets and if you need more than that there is a 12 outlet version as well. Your local dealer can help you with the specs, just know that this thing works and proves power is king when it comes to your systems sound and performance.
Remember that if your power is compromised then that snazzy new amp you bought will also be compromised. It will not perform to its full potential. If any of you own one of these, leave a comment below and let me know if it worked for you as well as it did for me.
One thing to take note of is that the Puritan can sound a little COLD out of the box. I found each hour it was on and in the system it improved. After a few days the sound is richer and slightly warmer and that is where it stayed. I am blown away by this product!
You can see more about the PSM 156 at the manufacturer website HERE.
See more of my audio reviews here.
NOTE: I have zero affiliation with any dealer or audio company. I paid full price plus tax for my 156 and did not even ask for a discount. Not a cent was made by me for this review. This is a superb product, almost like a well kept secret in HiFi. More people should be talking about the Puritan as its has no equal for the $$$ IMO.
UPDATE JAN 2023: I just updated every single power cable in my reference system to the Puritan Ultimate (Eight of them)!
What the PSM 156 does:
Rebalances the AC sine wave removing DC component, preventing transformer buzz and allowing them to breath properly at full efficiency.
Six 15 Amp Outlets each with independent refilter stages for both common and differential mode disturbances avoiding cross contamination between connected equipment.
52 cumulative stages of purification removes common and differential mode interference, enhancing clarity, staging and dynamics.
Equal resistance routing to all outputs realises full dynamic performance.
Integral earth management system inbuilt with cleansed ground and star earthing format further lowers the noise floor and further enhances clarity and dynamics.
Internal wiring silver plated OFC copper PTFE insulated.
Massive 9,000 Amps Repetitive Rating, three dimensional, non-sacrificial voltage surge protection.
Rated Voltage 110-250v AC 50/60Hz
IEC Type C20 Input
Electrically and magnetically shielded casing.
Manufactured in the UK
5 Years Guarantee
Hi Steve, I recently acquired a PSM156 and it works great…though my TT psu hums when plugged into the unit.I also noticed that all of the receptacles, even the c19 inlet,do not hold the cables tightly…they are in fact quite loose and will move up and down 20-30 degrees with the slightest touch. Is your Puritan the same?….I reached out to Puritan and they did not reply.
I have zero loose connections on the 156 but I use their cables for all of my gear. I also have no buzzing at all via the PSM or gear (when using the PSM). If bought from a dealer I would maybe ask for an exchange?
Thanks Steve….they told me PSM’s were all like this……hmmm…I’ll reach out to Puritan one more time.
Would the two work even better if run in tandem? IE, P20 plugged into the 156?
I wouldn’t think so.
Got the PSM156 after reading your review and honestly it has completely transformed my high end system in so many ways its laughable. Timing, bass, attack and decay got a huge leap towards perfection as if I got a completely new system. My tube power amp however still buzzes and hisses so I am thinking it is the output/driver tubes that need change.
Also I am contemplating to upgrade the stock power cord of PSM156 for an ultimate which I am sure it’s going to be worthwhile. Steve do you feel a full ultimate power cord loom is worth it compared to other high end offerings?
The Ultimate PC’s are well worth it, well, for me anyway. I use them throughout the system now and I am happy the 156 did for you what it did for me! Thank you and enjoy!
I did purchase the PSM156 and Ultimate mains specifically for a high end tube amp I recently purchased that produces transformer hum. The previous tube amp I owned was quiet in the audio chain. Unfortunately, the PSM156 had no effect on the transformer hum though it had other sonic benefits making the conditioner well worth the investment.
Interesting. My buzz is gone but maybe there are other factors there like an actual transformer that buzzes from something other than your power. I am glad it helped in other ways. Have a great day!
Your guess was correct. The amp transformer is the culprit. The Puritan remains in place.
I wonder if my NAIM SuperNait3 would sound better with Puritan PSM156.
My DAC is Chord cutest.
Have you tried SuperNait and Puritan PSM156 combination?
The PSM156 will help ANY system if you have any kind of power issues at all. If your system sound changes from day to day, you have a power issue. If you have any buzzes or noises coming from an amp, you may have DC on the line. I did, and the 156 cured it for me. I have since added seven Ultimate Power Cables for all of my gear. The 156 is the most important piece in my system. I have not tried it with the Naim but it’s universal at what it does.
I got a Puritan PSM156 three days ago brand new from a dealer and been using it for 5-6 hours/day.
I’m using it with my Supernait 3 but I’m considering returning or selling it back at a loss.
I think the sound becomes more refined for certain frequencies and vocals are more pronounced.
Overall feel is the sound is more delicate, lean and controlled but at the same time lose some liveliness, fullness and excitement.
I normally listen at low volume (50-70 db) so that might affect how I feel about the sound.
Going to run it for another couple more days and decide.
Interesting but thanks for your feedback! There is always the synergy thing. What power cable is powering the Puritan? I used the Ultimate and have not heard any other. I am so happy with it my system now uses Ultimate cables on ALL of my gear but these things seem to be system dependent. When I first put it in I noticed my sound was leaner, brighter and different from the PS audio (which was a darker sound) but over a week or two it opened up and doesn’t sound like that at all now. My system is refined, smooth, has more energy up top and wide open. Without the PSM it goes dull and has some grain as well. Oh, and my tube amp buzzes without it as well. With that said, it will not be for everyone which is why the return policy is great to have. Enjoy!
I think if you would want extra smoothness and warmth in your sound, it would be better to get it from another component like an R2R ladder Dac (my favourite one of the moment being Musician Aquarius with in-built OCXO clocks for just $US3,200). The power conditioner should bring in as a clear as possible an audio signal and then allow the other components to alter tonality to taste.
Just made the purchase online (156). My amp is the Leben CS600X and speakers are Harbeth P3XDs. Well Tempered Versalex tt with Dynavector 17DX and all connected with Tellurium Q Ultra Black ll. The anticipation is too much.
Enjoy it! I love mine, and it truly did fix the issues I had!
After watching your video by accident (though I am a subscriber I first thought that I don’t need to watch this one due to the “irrelevant” topic), I have found a local seller in Germany who also has a testing program – one can test devices free of charge for a week or longer. I have tested a Puritan Audio PSM156 for a week and didn’t want to miss it anymore – I am mostly a vinyl listener and though my equipment and especially my turntable (AVID Acutus SP) gives me already the sound I am more than happy with, the Puritan still had a very noticeable impact on it: the feeling of the stage is much bigger and somehow more relaxed and specifically for classical music – I could suddenly hear instruments even more separated from each other and some of them I couldn’t even notice before. I was stunned; normally I am very skeptical about such things, most of the time I think that I am just not such a good (or crazy) audiophile myself and wouldn’t be able to notice a difference. But not in this case.
That is wonderful to hear! Congrats! I love my PSM156 and am 100% content and happy with it. It does what it claims for sure. Enjoy!
“It’s so good I dream of one day replacing all of my power cables with the Puritan Utimate cables.”
No sarcasm intended, but what are you waiting for? It seems likely that the sale of your Cardas power cables would cover the purchase of replacements.
I owned one Cardas Power Cable and it would cover maybe 3/4 of one of the Ultimates at its resale price. : ) I do not have a spare $5k laying around for power cables right now. If I was flush with spare cash, I would in a nanosecond.
Why not use BOTH P20 and PSM 156, in series? I think you better grab a P20 to try!
I have a serious question. If you could have either the power plant p20 or the puritan psm156, with money not being a factor, which would you pick? I could get either or at the moment, and am genuinely interested in which is the better power conditioner/regenerator. Just purely on sound quality improvement. I do lean more towards warm. Thank you.
On sound quality alone the P20 is the better unit. While it did not fix the transformer buzz on some of the amps I have here as the 156 did, with it in the chain the sound was super refined, smooth, expansive and the bass was improved. The 156 tends to be on the brighter side. After a while with the 156 I do feel the P20 offered a better sound in my system with the regenerated power. Even so, the 156 also improves my sound yet in a different way. With the P20 your system will sound the same 100% of the time without any variations. With the 156 it’s about the same though not as rock solid. The P20 is $10k though so the value goes to the 156 without question. But if you want the the best for power, the P20 is about as good as it gets.
Do you think burn in would have an effect on the brightness of the psm156? Or do you think your unit is completely burned in by now and it’s just inherently bright. Do you still use the psm156?
The PSM 156 is not bright as I associate bright with lean, harsh and flat. It’s simply brighter than the P20 which is darker in comparison. The P20 sounds thicker where the PSM sounds more detailed and not as midband thick. When I say “thick” this is in no way a negative. I just mean that my system has more mid bass punch with the P20 and more airy treble with the PSM. Also, the PSM has been in since it arrived and I have not noticed any change from burn in at all.
Dear Steve, did you ever do some measurement of your incoming power? Did you analyse the frequencies? (FFT?)
Btw, that Luxman-hum is a common problem with all of their amps, regardless of price. I absolute hate noise and also light pollution, so all of my equipment is absolutely quiet and all of my displays can be turned off as well. Even if I turn my Enleum Amp up (without a signal!!!) to a volume that would blow my windows out, my speakers are dead silent. Wouldn‘t have it any other way.
My speakers are dead silent as well even with The Luxman. Was the same with the Enleum. I have an electrical issue with DC on my line and the 156 cured The Luxman transformer buzz completely (the buzz comes only from the transformer not the speakers). It’s silent now with the 156, without it, the buzz is there. When I had the 590 AXII (my previous home) it was also dead silent so I would not say it’s an issue with Luxman amps as it is obviously the power coming into my home. The 509X at a dealer was also dead silent. If someone has a Luxman (or any amp) that buzzes it could be they have DC on the line as I do.
I have put quite some time, effort and money into upgrading my power supply this year, also with significant improvements. My last addition was a NuPrime AC-4 Power Conditioner that works very well for me. At €850 it is very affordable, looks great and the red-and-green 1980s style display strongly reminds of the DeLorean time machine in BACK TO THE FUTURE! It shows the exact power consumption in Watt, Volt and Ampere. Fortunately, it can be turned off as well.
I‘m also a huge fan of Akiko Audio in the Netherlands. I have no clue how their entirely passive devices work, the claim is that they reduce high frequency pollution. The improvement in sound their tweaks brought to my system is quite baffling though.
Another tweak I recently aquired was the Tellurium Q System Disc. Very affordable and extremely effective, this one is definitely a keeper.