Rocking the Boat : Nord Hypex NC1200 Signature Amplifier

[CKKeung]

Here is a very interesting implementation of Purifi modules with linear input stage & powersupplies :
LKV Veros PWR+ power amplifier
https://www.stereophile.com/content/lkv-veros-pwr-power-amplifier

 

[Ric Schultz]

I am sure the LKV sounds very good. However, I doubt that it is any where near as good as my modded Purifi amps (even my baby stereo amp). The Purifi boards on the LKV amps are stock.....no air core inductors and modded caps.....nor bypassing the power connectors and input connectors......etc. etc. No binding post bypass system. My mono blocks are available with 3000 watt Hypex power supplies for each channel. Mono is always better than stereo. Modified mono blocks with 3000 watt supplies and possible added capacitance.....around $3500+ a pair. Do you see the steel covers and screws on the transformers in the above pics?.......closes down the sound. You want transformers glued to pieces of wood and mounted off the chassis.....then you get way more open sound. Stock fuse.....wimpy AC wires going to a power switch that wrecks the sound.....etc. etc. Lots of stuff to tweak there. But who is going to buy a $10,000 amp and have mods done?

I am so fussy......I have to do things in the most tweak (audio pure) way possible. Of course this is all talk.....need to walk too. I will have a stereo $2400 unit available in a month that will go out on tour.....and probably a pair of the big mono blocks after that for tour. Hearing is believing.

The stock Purifi evaluator board amp was already said to equal or beat the $40K mono blocks from Constellation. What I am doing is worlds better than that evaluator board amp.

https://www.soundstagehifi.com/index.php/opinion/1420-purifi-audios-pint-sized-powerhouses

Those evaluator board amps use a single 1200 watt Hypex power supply, two stock Purifi modules and a input stage based on an integrated circuit op amp.

By the way, the Bel Canto amps that Herb talked about in the review are just a 1200 watt supply, a stock Ncore 500 module and input stages based on a integrated circuit op amp ($6000 a pair).

 

[Hear Here]

Ric

I find this thread very confusing. You claim that the sound from Purifi module based amps can be dramatically improved by modifications in power supply, components, etc. Earlier, when I suggested that some of the big brand users of this technology (I mentioned the NAD M33) had the resources to modify the sound from these modules by doing precisely what you claim to be doing, some members here derided my suggetion.

Frankly I think they are talking out of their backsides! Of course the sound from Class D modules can be tailored to what the builder wants (within reason) in the same way, the designer of an 845-based tube amp can adjusty its sound. Who is right I wonder? Peter

 

[Ric Schultz]

The truth is very complex in audio. Most everyone has only a small piece of the knowledge of how things make sound.....and this includes manufacturers and techies and designers and users and reviewers....and includes super tweakers like me.

Let's look at something way more simple.......quarter mile hot rodding. There are only 5 factors that effect the performance......weight, horsepower, drag, traction and gearing.....plus the driver. Everything can be measured and everything is known to most everyone. That is why most top dragsters look almost identical. You can design a hot rod on paper and when you finish it.....it will perform almost exactly as you thought (within a quarter of a second and 10 miles per hour). Audio is nothing like this. Every single thing you do......changes the sound. And most of what changes the sound CANNOT be measured. Since there is no real "race course" in audio.....then there are no "rules" that are universal. Super tweakers....like myself, are rare. People who listen to wire directionality, cap directionality, damping, hard wire most things, eliminate everything not needed, using the worlds best parts and execution?.........these things are not practical for making money unless you charge a zillion dollars. MSB and Aries Cerat are pretty crazy.....but look what they charge. Do you really think NAD cares about how something really sounds?......well, slightly......but not at the serious tweak level. I told Nelson Pass about my wanting to mod his First Watt amps.......and also, that I was willing to come to where he was and help him tweak his products....for cheap or free. He responded with these exact words...."I know what you do works, but I have no interest in it. I don't care what you do to my amps....have fun." So, a very nice guy but he does not want to go down the rabbit hole of infinite tweaking.......I know all about that hole......infinite stuff down that hole. Nelson does not even use bypass caps on his amps.....one of the reasons they are not very fast. All a manufacture has to do is make them a little better every few years and all the old customers will buy the latest thing.

Look at the DAG Relentless amps.....quarter of a million dollars......and what do they use for binding posts? Custom made massive BRASS connectors.....yes, brass......50% copper and 50% zinc. You spend $10K for speaker cables and you connect them to a large hunk of brass? Would you buy brass wires or have your wires terminated with brass connectors?......not in this day and age! Why didn't they make them out of pure copper.....or OFC copper, or cryoed OFC copper, or PCOCC copper......MY GOD! at a quarter of a million dollars you run the output of the amp through a distortion producing connector? Low mass Furutech or WBT connectors would sound way better and my binding post bypass system would sound even better. I did send DAG an email about this, but I doubt they care. Where is the meticulous attention to details that effect the sound? BTW, the xlr input on the DAG is a five dollar retail Neutrik connector.

If you mod a Purifi module.....or any other module from any manufacturer.....then you lose the warrantee. This is one reason why no one has ever touched an Ncore or Purifi module (except me). I am not interested in plug and play. i am interested in sound.....making something sound great. If I have to modify something to make it better then I do it. If there is no longer a warrantee.....well, so be it. The Purifi modules are incredibly reliable. I do nothing that would change that. VTV has sold over 50 Purifi amps and not one channel (over 100) has gone bad. If a module were to ever fail, I would replace the bad module with another one with all the mods and we are back in business. The customer would have to pay me for the parts and minimal labor charge for the fix. The chances that that happening to someone are rare.....and the amp is so super cheap to begin with (relatively speaking) that no one is out much money. You usually only get 2 year warrantee with a new unit anyway.

When you do not know that much about how "every single thing changes the sound".....then you must rely mostly on a few reviews but mostly peoples talk about buzzwords......We then adopt these made up opinions about things as some kind of truth. A buzzword opinion is like: "Linear power supplies are better than switching supplies". Who says? Have these opinionated people actually played for hundreds of hours designing both linear and switching supplies and did serious listening tests? Not likely......well, never at all, actually. You have Rowland and Naim who believe that switchers are better. If you did everything to the ultimate.....which would win? If you put steel all around and inside your linear toroidal transformers......you close down the sound. A good switcher will sound better than a bad linear supply.....and visa versa......and what makes something good or bad is EVERYTHING you do.

So, it is no wonder that most all audiophiles are confused or limit their beliefs to a few buzzwords because it is impossible to know much of anything unless you get dirty and actually get crazy tweaky......which most do not have the time and inclination to do.

It is always best to listen yourself.....in your own home. This way, you choose the equipment you like and prefer. This is why I will have units out on tour.....so people can actually know something first hand. Hearing is knowing.

 

[Hear Here]

Do you really think NAD cares about how something really sounds?......well, slightly......but not at the serious tweak level.

With respect, what a ridiculous claim!

If manufacturers cared as little about the sound their products made as you suggest, they'd very soon be out of business - and deservedly so. NAD is a long-standing and large scale manufacturer with a reputation for building high value, mainly mid-fi equipment. They also offer a premium Master series where a great deal of R&D plus careful design and thought for customer needs go into these offerings. They still offer exceedingly good value compared with anything else on the market (apart perhaps from equivalents from othe big buildrs) and they have earned NAD a cupboard-full of Stereophile, EASA and other awards. They can only afford all this up-front cost because the resultant products are good enough to sell in big volumes. Of course they care about the sound, of course they carefully specify every item in the product and of course they will squeeze ever ounce of sound quality from modules developed by their suppliers.

 

[Ric Schultz]

Ah, a NAD lover......i pushed your button.....he he. Thank you for your intelligent and well thought out reply. All audio companies care about the sound. So, Yes, they care about the sound.......as I said...(slightly)....relative to what is possible.....the serious tweak level. If they cared about the serious tweak level then they would hire someone like me and the products would be as expensive as the wild stuff out there. At the level they are playing at they may be among the best, or the best and also the best value. They are not state of the art.....remember, this is the What's Best Forum. There is no way a NAD amp can compete with the big boys......Gryphon, Aries Cerat, MSB, D'Agostino, etc., EVS modified Purifi amps....he he. We shall see where my amps are. But they will be way, way above a STOCK NAD. They cannot do the hand made tweakiness, they are not using discrete regulators, and discrete input stages, exotic connectors, audiophile fuses, hand made wires listened to for directionality......they simply cannot do this at the price points they sell. They would make no money. This is true for most every "normal" manufacturer in that price range.

The M33 is a do it all machine......it streams, it DACs, it preamps, it amps, it pours coffee....it gives you a massage. It is not expensive and it may be the best all in one for the money. NAD themselves does not mention preamp circuitry, power supply circuitry, use of exotic super transparent parts, etc. etc. THEY KNOW what they are doing. They know the level at which they are playing......they might just be the bad boys of cheap. But they cannot complete on the Big Boys circuit. You cannot squeeze every ounce out of the Purifi module unless you mod it....and unless you use the most pure simple input stage using the worlds best regulators and power supplies and have most of the edge connectors bypassed , etc, etc, into infinity. There is normal.....and there is tweak. NAD is normal.....they ain't tweak. I am not saying NAD products do not sound good....they probably sound very good......but at the tweak level....or super tweak level? Not happening.

The Mola Mola Kaluga amps......are slightly tweak. Bruno hardwired the output wires, he changed the caps on the output to some Monolithic ones, he modified the power supply and output stage slightly.....use his own discrete input stage, etc. On the tweak scale......I would say a 45 out of 100. My modified NC1200 amps would be around 85 on the tweak scale. My amps will be around $4300 for mono blocks and the Mola Mola are $16.5K. My amps will have the 3000 watt power supplies (with some mods)....not the 1200 watters in the Mola Mola. My amps have options to use any and all of the discrete input op amps currently in production. My NC1200 modules will be modded with large gauge air core coils and modified caps, etc. Hand made tweaking is just not possible at low cost production line manufacturing......just not. However, you cannot make a lot of money doing what i am doing. What I am doing is an art.....a super small cottage industry thang. I can only modifiy 2 amps a week. If this goes how I hope then I imagine a waiting list will start to form very soon.

Everything I do to the Purifi amps I have done before.....except...one very important thing. And that is the air core coils......Every single class D amp that you have heard (except maybe the Merrill's) has ferrite core coils. Every single speaker manufacturer of serious high end speakers knows that ferrite core coils sonically suck when used in the xover on the mids and highs. So, why would you want to run the entire signal through a ferrite core coil? The very last thing the signal goes through before it leaves a class D amp is this coil. So, the sound will never get any better than the distortions of the coil. The distortions of a ferrite core foil are quite audible.......when you hear them removed you now realize that Class D is way better than you ever thought. You will see manufacturers in the future start to adopt air core coils....once the word gets out about the transparency of my modded amps.

 

[Loheswaran]

So who makes an Eigentakt amplifier?

 

[Ric Schultz]

Are you asking what companies are making amps using the Purifi module? If so, then:

1. VTV audio.......the cheapest one out there, free shipping, 30 day money back, 2 year warrantee and the currently the best to modifiy
2. Nord
3. Apollon
4. Audiophonics
5. NAD
6. March Audio
7. LKV audio
8. ATM audio
9. Rouge audio
etc.

Almost all of the above are selling direct......only NAD has dealers, that i know of.

 

[Hear Here]

Ah, a NAD lover......i pushed your button.....he he. Thank you for your intelligent and well thought out reply. All audio companies care about the sound. So, Yes, they care about the sound.

Ric

I hope you clocked on to the NAD M33 webinar discussion hosted by Stereophile today. Lot's from the Purifi designer that was far too technical for me, but perhaps you appreciated his lengthy description of the benefits of his design. Perhaps you have revised your views on this module as executed in the new NAD amp and could share them for the benefit of us less technically minder! Thanks

Peter

 

[Loheswaran]

Are you asking what companies are making amps using the Purifi module? If so, then:

1. VTV audio.......the cheapest one out there, free shipping, 30 day money back, 2 year warrantee and the currently the best to modifiy
2. Nord
3. Apollon
4. Audiophonics
5. NAD
6. March Audio
7. LKV audio
8. ATM audio
9. Rouge audio
etc.

Almost all of the above are selling direct......only NAD has dealers, that i know of.

Hi Ric

It appears that purefi use a demonstator called Eigentakt - it uses a specific configuration of the modules. Which of these manufacturers have an amp closest to this Eigentakt?

I am pondering between this and a hypex based amp

My main problem is actually getting to listen to one...

I was hoping to find a user in the UK who'd be willing to let me listen.

thanks

Lohan

 

[Ric Schultz]

Quote from Bruno: We decided to call our technology Eigentakt, an obscure German term for self-clocking or self-oscillating.

The modules nomenclature is 1ET400A......which I imagine to mean the: First Eigentakt ....400 watt Amp. They are working on a more powerful version now.

No, there is no such thing as a separate Eigentakt amplifier. Eigentakt is the NAME of the Purifi module. Just like Ncore is the name of the best Hypex modules. The Eigentakt circuit is Brunos latest circuit. The evaluator board amp is just two Purifi (Eigentakt) modules, a stock Hypex power supply and an input board with on board regulators for the front end buffer and a front end buffer using 1612 op amps.......not as good as using a discrete op amp. You can buy the Purifi modules and the input board from Purifi and buy a separate power supply from Hypex and case from China, etc. and put it in a box and you will have a "Purifi Evaluator board amp". It will probably not sound as good as a stock stereo VTV amp with Sparko Labs pro op amps that you can buy directly from VTV for $1350......which is about what you would pay if you bought the amp boards, power supply, case, jacks, wires, etc and assembled one yourself. And then there is the mods that I can do to that VTV stereo amp that take it to the moon (95% tweak).

In the UK, Nord makes amps using the Purifi modules and also has front ends using discrete op amps. Not as good of value as VTV....and certainly not very tweak but will give you some idea of the potential of the Purifi module (maybe 60%). i can also mod the Nord amps but that would not make sense for someone in the UK (shipping it to the US and back). UK customers are better off buying a VTV amp and having it sent to me and have me modding it and then just pay the $100? to have it mailed to the UK.....less money, easier to mod. Of course, my modded mono blocks using 3000 watt supplies, etc....are even better.

Please go back to pages 2 and 3 on this thread and read Elberoth's posts. He has Purifi and NC500 mono blocks from Nord. He says they are both very good but the Purifi sounds slightly better. He says the difference in sound between the different op amps you can install is greater than the difference between the modules......shows you how important implementation is. Like I said.....what Nord is doing is just the tip of the iceberg.

 

[analyzer]

Rick.. and for European users where 230v is the standard? Which is your suggestion?

 

[Ric Schultz]

Rick.. and for European users where 230v is the standard? Which is your suggestion?

You can change the voltage on the Hypex supplies in seconds by adding or removing a jumper. So, any Hypex power supplied amp can be used anywhere. The power supplies come without the jumper installed (set for 230). If you want 115V then you just add the jumper. That is why when you order from most places, they ask you what voltage you want because you cannot change it from a switch on the back of the unit. You have to open it. If I were sending a unit to a 230V country then before it leaves here I would remove the jumper.

If you download the PDF for the 1200 watt power supply you can see jumper 3 on the main pic on the extreme left. You can read about its function on pages 9 and 10

https://www.hypex.nl/product/smps1200a400/10

 

[CKKeung]

Hello Ric,
You mentioned that you preferred the 3000W model of the Hypex switching powersupply module.
Is it only more powerful or does it have other better performance when compared to lower models?
Thanks.

 

[Ric Schultz]

Hello Ric,
You mentioned that you preferred the 3000W model of the Hypex switching powersupply module.
Is it only more powerful or does it have other better performance when compared to lower models?
Thanks.

I am getting my first mono blocks with the 3000 watt supplies next week. No one in world has ever heard this yet....as far as I know. Bigger power supplies almost always sound better......lower impedance, better slam, dynamics, etc. Looking at it compared to the 1200 watter.....you have a bigger fuse (30Amp, not 12 amp)....bigger fuses have lower resistance and sound more pure.....you have a larger on off relay (lower resistance).....you have a larger gauge rf filter coil, you have more than twice as much input capacitance, larger power transformer and more caps on the output. I would be shocked if it did not sound much better than the 1200 watt supply. You are only using a maximum of 500 watts with a Purifi module.....so some would argue that a 1200 watt supply is overkill. I have never heard of overkill......not in my vocabulary. PS audio, in the early 80s had a preamp that used a giant external transformer......because it sounded better.....so their 5 watt draw used a super big tranny.(way over 100 watts, I believe). Just found a pic....see below. Bigger is almost always better.....as far as power supply goes. I am also going to try to add some 10,000 uf Mundorf caps on the output of the power supply. Not sure if the power supply will like it....but I saw a DIY post of someone using some 6800uf caps on the output of the 1200 watt supply.....so, I am pretty sure it will work. By the way, I will be hardwiring the plus and minus 64 volt rail wires into the power supply module. Probably using 14 gauge or double 14 gauge cryoed OFC with foamed teflon. Then it will be hardwired at both ends......got to get TWEAK!

This was for a preamp:
https://www.ebay.com/itm/PS-Audio-M-500-Power-Supply-/274418359696?item=274418359696&ViewItem=&nma=true&si=SiDSwbgz9Xl%2FIC5VJyjcCwRNPpk%3D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

 

[CKKeung]

Hi Ric,
Thanks for the explanation.
I chatted with Romaz a while ago and he also thought that there wasn't the word of Overkill in the vocabulary of PSU.


I listened to many Ncore poweramp.
Most are very authoritative and dynamical yet their musicality aspect is wanting.
The mid and treble are often lacking continuousness and sound a bit mechanical.
And their treble is often harsh or deliberately rolled-off (an imperfect cure for the former problem).

How do you tackle the Achilles' Heels of class D amps?
The Mundorf caps may be one of the remedies, I think.

 

[analyzer]

Thank you Rick for the detailed answer!!

 

[Ric Schultz]

How do you tackle the Achilles' Heels of class D amps?

There are lots of limitations in any class of amplifications. When you are dealing with solid state then the more you tweak the more you achieve both clarity and musicality. Tubes naturally make things "sound better". Solid state (done correctly) has less signature........oh no....i just put my foot in my mouth.....he he. Fire away, if you must. Anyway, solid state is less forgiving. If you have one single thing not done correctly using solid state then it sticks out like a sore thumb. So, you must tweak EVERYWHERE.....which is, of course, always the best solution.

Has any serious tweak company made an amp using Ncore modules? Not that I can see. You had Merrill throw them in boxes with a better fuse and wire. You have Theta use some linear power supplies.....and some like it. You have Bel-Canto throw them in a box and add an op amp on the input ($6K a pair). The only implementation that was any way tweak was the Mola Mola......and it is maybe 30% tweak (maybe 70% of what is possible). Probably the best sounding stock NC1200 amp is the all out Apollon (over 7K for the pair) talked about in this thread. I would say a 40% tweak level. Those amps are not suitable for my mods as the modules are mounted vertically.....and they are too expensive to mod.....no value there. My modded mono block NC1200 amps will be far superior.

It's quite obvious that using ferrite core coils have been one limitation for class D. I have solved that problem. However, there is always more to do. Some say the GaN transistor will save us. Bruno does not think it is necessary. Certainly the two expensive brands of class D amps using GaNs are very very good. However, they start at $7500 for a medium power AGD and $16000 for the cheapest Merrill. How much is their good sound based on GaN and how much is just better implementation? These are from the ground up designs......not someones modules (stock or modified).

I am taking the Purifi and NC1200 modules to the moon. But how high is that? What if my all out Purifi mono blocks (around $4K) or NC1200 mono blocks (around $4800) play in the league with these GaN amps or even? better? The Purifi version is about half of the cheapest AGD and one quarter the price of the cheapest Merrill. We shall see.

Below is a pic of the Stock VTV amp using the 3000 watt power supply, the Purifi module and the VTV front end board using Sparko labs regulators and has the Pro Sparko labs discrete op amps installed. A pair of these is $2228 delivered. This pic taken on a bench at VTV. I will have this amp.....and its brother....next week.......then the fun starts with all out mods. This is a world's first.....mono amps using a 3000 watt power supply with the Purifi modules.

I just now found out that if you click on the picture and then double click again you get a mucho bigger pic that you can move around.....way cool this internet thang!

 

[Apollon]

Hello everybody,

I would like to chime in and share some important facts regarding our PNC1200 amplifiers.

1. Using the Hypex SMPS3K/A700-A400 (3800 watt) power supplies with half bridge class d amplifier modules like the NC500, NC1200, Purifi 1ET400A is not the best choice. This is especially important when using the Hypex SMPS3K power supply in a mono block configuration. The Hypex SMPS3K power supplies do not feature the 2-quadrantoperation as most other Hypex SMPS power supplies do. Therefore, they are unable to handle large reverse currents generated by half-bridge amplifiers operated at low frequencies. For this reason, it is not advisable to use the Hypex SMPS3K to power half bridge amplifiers like the NC500, NC1200 and Purifi 1ET400A modules when used in the frequency range below 100Hz. Hypex does not recommend using this power supply for half bridge class d amplifier modules either. This is the main reason why we have chosen to use the Hypex SMPS1200 power supply which is designed for the NC1200 module and other half bridge class d modules.

2. The NC1200 modules in our PNC1200 premium amplifiers are not stock modules. The modules are modified. The stock NC1200 class d modules have a THD+N reading of 0.001% and the modules in our PNC1200 amplifiers have a THD+N reading of 0.0005%. We achieved far lower harmonic distortion with our implementation and mods.

3. We use pure occ copper and pure silver wiring and pure silver binding posts so no mods are needed here. Trust me

4. Our custom linear power supplies in our PNC1200 amplifiers are also powering the modulator stage of the NC1200 module as well. They are not powering just the input stage like mentioned above. Clean power for the input stage and modulator stage is very crucial and it is very audible.


Best regards,

Tibor Marksel
Apollon Audio

 

[Ric Schultz]

Have you listened to the 3000 watt supply on a single Purifi amp module (mono amps)? If so, how did it sound different from the 1200 watter? This is what really matters.....the sound. Since you believe what Hypex states......you probably did not go out of your way to buy the lower voltage power versions of the 3k supply to test on a Purifi. But maybe you tested the high voltage version on the NC1200? By the way, power supply pumping can be mitigated by the use of large value capacitors on the power supply. There is not much capacitance on any Hypex or Purifi module....nor on the output of any Hypex power supply. So, even without power supply pumping better sound could be achieved by adding capacitance near the output stage. I am getting some 10,000 uf caps in this week to try on my 1200 watt supply and on the 3000 watt supply. This could be a major breakthrough even on the 1200.....we shall see/hear. Rowland has a bank of capacitors they add in their $6000 535 amp (using a stock Pascal stereo module). He did this to improve dynamics, slam and transparency. You can see the 10 added caps in this pic:



All connections degrade the sound. The output wire on the Apollon amp is crimped? into a connector on the amp module and then soldered? at the other end to the silver WBT post. This is very good. However, if you took the same wire and soldered it to the NC1200 module (Bruno did this in the Mola Mola) and then ran it outside the amp like I do and wrapped it around the outside of the binding post you would hear lower distortion sound. You cannot add connections and silver anything and get lower distortion. The silver connector could make it "sound" more detailed then even the straight wire. I did a straight wire bypass test on the silver WBT RCA connectors and found the they actually fool you into thinking it has more detail because the upper mids are pushed forward. The straight wire was less forward but had more inner detail. This is the problem with silver.....almost always has a "silver sheen".

When using the Purifi modules the modulator stage is also powered by whatever regulators you use on the front end. We both use Sparko labs regulators. I modify mine for better sound. You really want the regulators as close to the circuit as possible. Having a bunch of connectors in series with this power supply distorts the sound, as well. The regulators and super output caps should be right next to the input stage and also hardwired directly to the modulator stage (no connectors). I do this. If you put a steel shield around a toroidal transformer you close down its field resulting in loss of transparency. If you need to shield, then keep the shield at lease one inch or more away from the body of the transformer and never use ANY metal inside, on top of or directly around the transformer.....isolate the transformer using wood and use glue or tie wraps to secure......much better sound.

Every single thing you do anywhere in the AC power, DC power and amplifier stages effects the sound. Let us just look at the AC power.

The first thing the AC sees is the AC receptacle. If you are not using a Furutech AC inlet then you are not hearing the potential of the amp. If you use a power switch, you are degrading the sound. If you use a stock fuse (it looks like two stock fuses in series in the Apollon amp...one in the external inexpensive fuse holder/inlet/switch combo and one on the power supply) then you degrade the sound. If you crimp wires in the AC power and use extra connectors then you degrade the sound. If you use a soft start, then you degrade the sound. A soft start is more wires, connectors and a relay....all in series with the AC signal. There are tons of amplifiers using Hypex power supplies without soft starts out there....I don't see any reliability problem. If you get rid of the power switch then you rarely even have turn on surges. The shortest and purest signal path always wins. I use a Furutech inlet that I modifiy so I can solder a fuse holder directly to it (no extra wire). I use no power switch. I then hardwire (solder...not crimp connections) 14 gauge foam teflon insulated cryoed OFC copper AC wire directly from the AC inlet/fuse to the input of the power supply. Yes, I solder to the power supply.....no connector. I then remove the stock fuse on the power supply. The single fuse that comes standard in my amps is a Create Audio fuse (inexpensive, yet much better than a stock fuse). Obviously, one can easily change that fuse to one of the sonically more advanced jobbies. By the way, Merrill also uses no power switch on any of their products.....go Merrill! Some people buy $10,000 power cords just to get the power as good as possible to the amp. You do not want to lose all that goodness by using stock fuses, switches, ordinary wire, relays, ordinary connectors, etc..........everything.....everything matters in audio.

Everything that I do follows this super pure tweaky (listened to) signal path execution. Elimination of every connection possible. Use the best wire possible. Use the best parts possible. Modifiy to make better. Damp parts by listening (you can overdamp). Everything that I am doing on these modified amps I have done before except one very important thing: This is the elimination of the distortion producing ferrite core coils on the amps. This is a breakthrough. When you hear the purity and speed and soundstage that a great air core coil brings.......OMG! All class D amps (except maybe the Merrill's) have a ferrite core coil on the output. I dare you to go inside your speakers and remove the air coil core coils on your midrange and tweeters and put in ferrite core coils.......if you did this you would go screaming out of the room......you would want to burn your speakers....he he. You will see manufacturers (hopefully Purifi someday) start to play with this and realize that all these years we have been limiting the sound of our class D amps with magnetic material.

I have been tweaking and modding high end stereo gear since 1977. This old guy has learned a lot...and has a lot more to learn. The Apollon amps are great, I am sure. However, this audio game is infinite. The more I learn, the more I learn I know nothing. There is always someone who has learned more, who has tried something you have not. We are, hopefully, always learning. Most of what I do I have learned from others. We are all in this together. May everyone enjoy this moment......and every moment.....the best they can.