Rocking the Boat : Nord Hypex NC1200 Signature Amplifier

[CKKeung]

Doug Schneider measured the purifi module :
https://www.soundstagehifi.com/inde...asured-performance-of-the-eigentakt-amplifier

Hello Tibor & Ric,
Any comments?
Many thanks!

 

[Ric Schultz]

We already knew it measured great......Audio Science review measured it too. If you use a different op amp on the input that does not have as low of measured distortion as the 1612 op amp (the one installed on the Purifi board) then the distortion measurements would not be quite as good. However, a lot of discrete op amps (that don't measure quite as good as a 1612) give a more transparent and dynamic sound (and all these discrete op amps all sound different from each other). This is why many companies that sell the Ncore and Purifi amps give you a choice of input op amps and you can always change them for another sound flavor, down the road.

Measurements are just one factor. All wire measures the same on a distortion meter. All wire sounds different. Same with solder, jacks, caps, resistors, removing connectors, damping, etc. into infinity. Most things that make for better sound CANNOT (at this time) be measured. The guy at March Audio believes his 1632 op amp that he uses on his Purifi amps is the best because it MEASURES better than anything. So, he thinks any other op amp is DISTORTING the sound. He is one of the guys that are part of the Audio Science review cult. These people believe only in measurements (so they love the Ncore, Purifi and Benchmark amps)......but they actually believe everything sounds the same. You know, the total objectivists. I feel sorry for them. They have nothing to tweak. They cannot ever improve their system unless they get a new piece of gear that measures better but actually sounds the same......well, they think so. To each his own. That forum is the last stand for the total objectivists......in fact, they banned me. They want no dissenters posting there.

What is cool about the Purifi and Ncore modules is that they measure great and sound really good when implemented in serious ways. I would take on modding the Benchmark amp but it is way complicated and crammed with stuff. It would take me months to work up a decent mod. It measures like the Purifi.....check out the measurements on Audio Science review........just don't post anything about "listening tests" or such or they will throw you out.......However, being banned by flat earther's is an honor. If you go to the edge of the earth......you will experience the fact that the earth is round. If you actually did a listening test with open mind and heart....you would experience differences in everything. Let us all be open to experience.....the great wonder of life as it breaths its joy into us with every breath.

There is no perfect anything on this plane. There will be even more transparent class D amps and modules coming down the line. Same with class A and tubes. This has always been so. It will always be so. Enjoy the ride.

 

[analyzer]

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:

View attachment 68856

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.

Rick... you suggested a lot of improvements to Apollon and all other manufacturers.
I wonder if these upgrades can be actually implemented in a stock amplifier, following the rules of safety and applied to the production of all units.
Very interesting thread...
Marco

 

[Apollon]

Yes I have listened to the 3800 watt supply on a single Purifi 1ET400A module, NC500 module and NC1200 module. The power supply is actually 3800 watt and not 3000 watt btw. The difference I heard was that with the SMPS1200 power supply the bass performance was clearly better. There is just more weight to the sound with the 1200 watt power supply. It seems like the bass extends lower and especially at 80Hz and lower I heard a dip with the 3800 watt power supply. It seemed like something is missing especially at 40-80 Hz. I don't know which speakers you use for testing but on our system the bass performance was a lot better and punchier with the 1200 watt power supply. It just sounded right compared to the 3800 watt power supply which sounded bass shy in my opinion. Like I've mentioned before 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. This is the main reason why the difference in bass performance when using the 3800 watt power supply with half bridge class d modules is so audible. The problem can not just be solved completely with adding capacitance. Trust me we already tried that. Adding capacitance can work sometimes but sometimes it can also make things worse. It is not necessary that it will always improve dynamics, slam and transparency. The only way how to solve this was adding a second half bridge class d module to the 3800 watt power supply and putting the second module out of phase or bridging both half bridge class d modules. When doing this the bass performance was immediately improved and was the same as with the smaller 1200 watt power supply.

I'm a professional mastering and mixing engineer for the last 21 years. I have a very very trained ear since I use my ears for living my whole career. I am trained to use my ears to hear the slightest change in eq, compression, volume, distortion etc.... I always trust my ears first when auditioning audio gear and this is how I always start evaluating audio gear. After I make the listening evaluation I use high precision Audio Analysers for measurements and I also use a high precision measurement microphone so that I can measure the actual response from the speakers. I don't rely purely on measurements at all. Measurements are just a tool and just one of the aspects when designing audio gear. My first and most important tools are my ears. But measurements come handy especialy when fine matching stereo channels and when trying out different passive components or identifying a problem in an electronic circuit.

There are lots of DAC's, preamps, amplifiers I have came across that measure the same or almost identical. Do they sound the same? Of course not.

"All connections degrade the sound."

I would not fully agree with this statement. I would like to share my opinion and findings. For instance the JST connectors used for mains power on the power supplies and for the main rails are very high quality. We have tried soldering the wire direct to the power supply and it made no audible difference. I could not hear any improvement or difference. Soldering the wire right into the board for the main DC voltage rails that go from the power supply to the class d amplifier module also made no audible difference. The only difference that I heard and was also measurable was soldering the speaker wire to the amplifier board. But let me explain why we have decided to crimp the wire to the connector in our PNC1200 on the amplifier module side. We use a 12AWG occ copper wire with added 18AWG pure silver wire. The 12AWG occ copper wire outperformed a 14AWG occ copper wire in our test hands down. The 12AWG occ copper wire just has more body and weight to the sound. This is the reason we have chosen to use the 12AWG copper wire instead of 14AWG. The drawback with using 12AWG is that we can not solder the wire directly to the amplifier board. The wire is just to thick to fit in the holes after the JST speaker output connector is removed from the amplifier board. I compared two PNC1200 prototype setups. One had a 14AWG copper + 18AWG silver wire soldered to the amplifier module and the other had 12AWG copper + 18AWG wire crimped like in our final version of the PNC1200. In the listening sessions the 12AWG + 18AWG setup outperformed the 14AWG + 18AWG setup hands down. Again the results were more body and weight to the sound. We found a great balance with all components in our PNC1200 so this is one of the reasons why our PNC1200 amplifiers got so popular and are sounding this good.

This is the problem with silver.....almost always has a "silver sheen".

The reason why we have chosen to use the pure silver was that the WBT pure silver binding posts simply sounded the best from all the binding posts we have auditioned. Like you probably know silver is a better conductor than copper. In our testing phase we have tried all kinds of binding posts from Furutech, WBT, ETI, Cardas, Audio note etc... The WBT 0703AG pure silver binding post beat them all. It sounded just as good as pure wire with no coloration or added artefacts. Just should give these binding posts a try. They are really really good. They are expensive but worth the price.

My findings with adding a pure silver 18AWG silver wire to the 12AWG are as follows. When adding the pure silver wire to the 12AWG occ copper wire we achieved more detailed and smoother highs. I believe that it is not a "silver sheen" or some "character" added by the silver but more detail in my opinion. The result is crystal clear and smooth highs. Most very very expensive speakers cables use a combination of pure occ copper and pure silver as well.

The regulators and super output caps should be right next to the input stage.

The regulators and caps are very close to the input stage in most of our builds. Speaking of Sparkos regulators, they are very good. But I must share a great finding. We tried two LT3045 in parallel and two LT3094 in parallel and by surprise they outperformed the Sparkos regulators sound wise and they measure a bit better as well. Maybe we will use the LT3045 and LT3094 in the future instead of Sparkos regulators.

Having a bunch of connectors in series with this power supply distorts the sound, as well.

I'm sorry but I can't agree with this statement. Harmonic distortion is audible and also measurable. Very precise Audio Analyzers come very handy in this case. Even the slightest change in harmonic distortion would be visible in measurements. I use the ATC SCM 150 as my surgical tool. They are not the most enjoyable speakers that I have listened to but they are the most surgical and precise speakers that I have come across. They have ATC's SL drivers that are known as one of the lowest distortion drivers on the market. Even the slightest distortion in the audio material or in the audio chain is very very audible on these speakers. I hear no added distortion because of the connectors and I also can't measure any change in harmonic distortion. We have made tons of test over the time. For instance if our PNC1200 harmonic distoriton measurement is 0.0005% THD+N by default, this harmonic distortion doesn't drop with soldering the mains power cable direct to the power supply etc...

As for customisations like adding a Furutech mains inlet or similar we are always open to do such customisation if a customer desires this.

If you crimp wires in the AC power and use extra connectors then you degrade the sound.

I disagree as I can't hear no difference or measure it.

If you use a soft start, then you degrade the sound.

We don't use an additional soft start module in our amps. We use the soft start feature that is built in the Hypex smps power supplies. The AC MAINS inlet is connected direct to the splitter on our control board and from the splitter to the power supply. There are no additional soft start modules in between. The front button on our amps is just for controlling the standby mode. The only mains switch is on the back at the AC mains inlet. Like I've mentioned before, this can be customised if a customer desires it.

 

[Apollon]

You do not want to lose all that goodness by using stock fuses, switches, ordinary wire, relays, ordinary connectors, etc

We don't use ordinary wire or ordinary connectors. Pins in the JST connectors that are on the Hypex power supplies and NC1200 module are pure copper and the fuses are not the cheapest fuses at all. All cables are custom made. All the wire that we use is OFC and OCC pure copper and pure silver. WBT pure silver connectors are far from ordinary connectors.

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.

Well here it gets very interesting. I'm a big fan of very good air coil inductors. Especially in passive crossovers. But in class d power amps it gets a bit tricky. There is a reason why all companies that make class d modules stick to ferrite core coils.

I agree that air core inductor never saturates unlike ferrite/iron core inductor but it requires larger number of turns to realize a given inductance value. Air cores are free from energy losses called "core losses" that occur in ferromagnetic cores as the frequency increases. So the air cores are very effective as long as the windings are rigidly supported enough to avoid "microphony" (mechanical vibration of the windings can cause variations in the inductance).

How do you support the windings?

The ferrite/iron core inductor that is part of the output filter of the class d module is very crucial I agree. Changing the inductor can have a very big impact on the sound and measurements. One of the advantages of ferrite/iron core inductors is that there is less EMC problems than using air-core coils.

These class d modules are calibrated so they all perform and measure almost identical.

How do you calibrate these class d modules after you change the inductor?

How do you precisely match both channels after your change the inductor for optimum soundstage?

You mentioned that you make your own custom air coil inductors.

How do you fine match all inductors so that they all have the same inductance value?

Even the slightest change in the inductance value can have a big impact on the performance. So for instance if a custom inductor on one channel has a little bit different inductance value than the custom inductor on the other channel the performance and soundstage can be very degraded.

We tried changing the inductor on the nc1200 in the past for a air coil inductor. It was one of our tweaks that we wanted to do. The outcome was far from good. The nc1200 with the air coil inductor measured and sounded catastrophic with a big rise in THD+N. I still have these measurements and I can show you the very bad impact this mod had on the sound and measurements. The harmonic distortion was raised dramatically.

Maybe the improvement you hear can be attributed to a raise in harmonic distortion because of the air coil inductors used instead of ferrite inductors. I don't know. I'm just guessing. In our case this modification was sadly not an improvement.

I would love to see an unbiased review of our PNC1200 versus your modified NC1200 based amplifier in the future. Above you described your modified amplifier as 60% better sounding as our PNC1200 and that your modded mono block NC1200 amps will be far superior. Have you had a chance to audition our PNC1200 amplifier so that you can make such assumptions?

 

[Apollon]

Rick... you suggested a lot of improvements to Apollon and all other manufacturers.
I wonder if these upgrades can be actually implemented in a stock amplifier, following the rules of safety and applied to the production of all units.
Very interesting thread...
Marco

I would not agree that all these "improvement statements" from Mr. Schulz regarding our PNC1200 amplifiers will be actual audible improvements. We have done a lot of testing before releasing our premium amplifiers.

Regarding the safety aspect. We sell a lot of amplifiers and we build them according to CE standard that is very strict and for a good reason. You do not want your product to be responsible for injuring someone or burning down their house. The way mister Schulz modifies amplifiers and enclosures is beyond any safety standard. For CE approval for example everything must be properly insulated and there must be no bare wires or connectors on the outside of the product to avoid any accidental contact with the terminal.

 

[Ric Schultz]

From what I can see all Hypex amps are half bridge. That would mean that the 3000 watt supply should not be used at all on Hypex amplifiers. I notice that Apollon uses the 3K supply on the mono 2K modules. It looks to me like the 2K module has one input modulator stage and two half bridge output stages. You can use the output stages separately to bi-amp or use them in parallel for more power. So, is there no power supply pumping on the 2K module when you use the 3K supply? I am emailing Hypex today about this discrepancy. How could they make a power supply that cannot work well with any of their amps? Is the 2K module different from what I think? Again, I will be asking Hypex about this.

Just talked to Hypex. Apparently the NC2K if fully bridged...so using it with the 3k supply is no problem. All other modules from Hypex are half bridge (and so is the Purifi). I asked about adding capacitance to "fix' the problem and he said: "it may work, but they do not support it." I joked with the guy about adding a million microfarads like the Mephisto has......he did not reply....guess he does not think that is funny.

The main reason why people don't put extra capacitance on switching supplies is because switching supplies are suppose to be small....that is the whole idea......and because they are not operating at 60hz then you don't need big output caps to smooth the 60 hz ripple. However, a power amp needs lots of current.....small caps do not do the trick. The big Grypon Mephisto amp has one million microfarads of capacitance......it sounds outrageous. I will see what adding 10K uf and 20k uf to each rail will do for the sound. All caps sound different and how you implement anything is very important. One main thing most do not do is bypass every big cap.....right on the cap. Big caps are somewhat inductive and they usually need a fast bypass cap for best sound. My modified Wima caps kick serious booty.

I personally doubt that Apollon ever tried hardwiring anything because they are a "plug and play" company. They need to make money. You cannot make money hardwiring or modifying things. No one in the world except crazy me would try.....let alone, do the things I do. You cannot make much money doing what I do. You cannot support a family. All the plug and play companies are trying to make as many amps as fast as they can. If you hardwire, make your own wires, modify caps by hand, make your own inductors, etc. etc. you would have to charge 2 to 3 times as much......and what employee are you going to trust to do work so refined and tweaky? No, you want to plug and play. If you modifiy the Hypex power supply in any way...you lose the warrantee from Hypex. If you modify the Hypex or Purifi module in any way......you lose the warrantee. You want to be able to swap out very quickly any bad part for another and also be able to get your money back for the defective part. Modding does not work that way. My modded amp modules are not covered by the manufacturer. Most of the companies that are making Hypex and Purifi based modules are "Plug and play' companies. LKV is using linear power supplies and their own input stage but many things are still not done very tweak. Apollon is making the best "plug and play" amps.....from what I can see.

Power supply connections are harder to hear than signal connections. However, here is a my experience with AC stuff. Last year I made a dual mono stereo amp using the IceEdge modules. When I was first evaluating the modules my AC inlet was a cheap one dollar Shurter and the 5 inches of soldered AC wire to the board was doubled up 16 guage stranded with PVC insulation. Take Five Audio in Canada makes a cryoed version of the Shurter inlet ($2.50?).....so I tried that and yes that was noticeably better. Then I tried a Furutech pure copper inlet (these already are cyroed and demagnetized) and that was another big level up in sound. I then changed the AC wire to some Canare wire I had here.....stranded copper with polyethylene insulation....and that was better than the PVC wire......then I went to doubled up 13 gauge Furutech wire......OMG.....that was way better. Remember, this is just a five inch piece of wire. If you run the AC through all kinds of connectors and ordinary wire, splitters.....etc. you are wrecking the sound.....no doubt.

Everyone agrees that signal connectors can make a world of difference. On the input of the Apollon amp there is a connector for the input wire on the buffer board. This is a standard Molex or whatever connector. They are not OFC. cryoed OFC or PCOCC......just ordinary copper connectors. Then there is another connector coming out of that board....and another connector on the amp board.......so three ordinary connectors in series with the audio signal. I have no ordinary connectors.....I have no connectors. I hardwire the input wire from the XLR directly to the input of the input stage. I hardwire the output pin of the input stage directly to the input modulator pins on the Purifi module. No connectors what so ever. The shielded cables coming from the input jacks to the input board and from the input board to the output board look pretty ordinary on the Apollon amp......Are they some super wire? Is it really OFC or PCOCC? What brand is it? I use my own custom made and listened to wire......and the wire must be used in a particular direction for best sound. I like my own wire better than parallel silver/gold Neotech wire.

"And the fuses are not the cheapest at all"......what the heck does that mean? Do you have any idea how much an audiophile fuse can change/improve the sound? I am sure you are using at least a $1 fuse on the back inlet......what maybe $2....is that what you mean? The fuse on the 1200 watt Hypex module has soldered wires on it (a pig tail fuse). It is soldered into the board and sticking straight up in the air. It is then wrapped with heatshrink and then glued at the bottom with silcon glue. The stock fuse costs $1. So, did you remove all of that and try some $2 fuses with pigtails and then soldered it in and put heatshrink around it and re-glued it down? No, you would not want to touch the power supply because you would lose the warrantee. The fuses you use are not good......and you only need one fuse. Since you are taking the AC separately for your linear supply then you need two fuses.......only one will be in series with the linear supply but both are in series with the switching supply. A good solution for you to try is to run the linear supply from underneath the switcher after the AC filter. Then you could remove the fuse on the switcher and then get an audiophile fuse for your one and only fuse. However, you would again have to modifiy the power supply.....which, i am sure, you won't do.....because you are plug and play.

 

[Ric Schultz]

If you did listen to an air core coil.....you did not listen to the right one implemented in the most tweaky way. The value of the inductor is not super critical......I do have an inductance meter and I match my inductors to the exact value that is in the stock module. Pretty simply really. However, if it were slightly off I don't think you could hear it. I doubt you listened to inductors that were slightly different and heard a soundstage shift. Remember, this filter is at 50K!!!!!!!!!!! So, if it rolled off at 48K or 52K you are going to hear that? Again, i doubt you ever did that test. That would be a stupid test to try....of course, you are going to match the inductors. The caps to ground on the output of the amp effect the rolloff the same way. The Wima caps used are, I believe, 10 % rated. At least there is a 10 printed on the backside. So, what if one module had all 6 caps 10% low and the other module 10% high? Does Purifi and Hypex match all 12 caps.......no they don't. i have measured them and most are all pretty close but some are way off. However, when I mod the caps on the output I do match each set of 6 to each other very closely......way better than stock. However, if i did not match them I do not think it would make any sonic difference. Since I am modding the caps and then I test each one with a meter when done then it is easy to put them all in a numerical order and do it. No biggie. However, WAY MORE IMPORTANT: if the caps on the output are not modified and put in the best sounding direction (all outside foils to ground) then you are not hearing what the module can do.

Some of the coils I tried were way worse than the stock coil. However, the coil I finally came up with is way, way better than the stock coil. At the time I was listening directly out of the amp into my modified Sennheiser headphones. When I put the better coil in the soundstage jumped 2 inches outside where it was from my head. Every instrument was faster, cleaner, more dynamic and more involving. I wish I had 4 sets of ears and 4 heads as I kept jumping from one instrument to the other going OMG....did you hear the drum....then a second later the sax would grab me with another OMG and then the bass, etc......it was thrilling. The stock coil is compressed and veiled and slow and boring. Wait till you guys hear this!

No one has ever had a problem with my binding post bypass system. The wire that wraps around the binding post is soldered to itself and the loop is smaller than the diameter of the nut so it does not stick out. The wire is insulated with teflon. There is no safety issue. If you have large spades then they will stick out further and that is where you could get a shock from. My amps have Touchless connectors......many amps do these days......but not all amps. Check out the big brass posts on the D'Agostino Relentless amps. Tell your kids to hold on to those connectors while you play some speakers at 120db........that would be a shocking experience.....he he. I notice one pic of a rubber sleeve put over the tip of them.....probably a good idea!

I have been in this business since the late 70s.....no one has ever had their house burn down as a result of using any product that I made or modded (that is a long track record). Let's keep it real. My products are safe. They may look wild, but no way would I make something that would endanger anyone.

As I always say.....do not believe anyone....certainly not me. Only believe your ears. What I do will never be done by anyone else.....ever. Some of the things I do can be implemented in normal production. For instance, Purifi, could put properly polarized caps and an air core coil in their next amp......the module would have to be much, much larger. Someone else could do this down road in their "from the ground up class D amp". All my ideas are available to everyone. I want everyone to hear what can be done. We all deserve good sound......and we don't need to spend a fortune getting it.

The Merrill amps are probably the first attempt by anyone at actually trying to make a serious class D amp. Most class D amps are plug and play module amps. Merrill uses damped chassis, super jacks, good feet, their own circuit using zero feedback, GaN fets, and whatever other goodies they have inside. They do not allow anyone to see inside so what is in there is hush hush. Most all reviews are pretty darn favorable. However, the cheapest one is $16K. If you put the guts of those amps into a normal chassis and sold them direct they would cost one third of what they sell them for. What if my amps are close or as good as those mega buck amps.....wouldn't that be cool!?!
Happy listening.

 

[CKKeung]

Hello Tibor & Ric,
This "Rock the Boat" thread has become very educational lately!

I am sure all readers, both audiophiles and experts in the audio industry have learned a lot from your discussion.

Thank you for your generosity, sharing many of your discoveries with us.

I sincerely hope that this thread can remain a well-mannered discussion and continue to give us CHE (Continuous HiFi Education).

 

[CKKeung]

Yes I have listened to the 3800 watt supply on a single Purifi 1ET400A module, NC500 module and NC1200 module. The power supply is actually 3800 watt and not 3000 watt btw. The difference I heard was that with the SMPS1200 power supply the bass performance was clearly better. There is just more weight to the sound with the 1200 watt power supply. It seems like the bass extends lower and especially at 80Hz and lower I heard a dip with the 3800 watt power supply. It seemed like something is missing especially at 40-80 Hz. I don't know which speakers you use for testing but on our system the bass performance was a lot better and punchier with the 1200 watt power supply. It just sounded right compared to the 3800 watt power supply which sounded bass shy in my opinion. Like I've mentioned before 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. This is the main reason why the difference in bass performance when using the 3800 watt power supply with half bridge class d modules is so audible. The problem can not just be solved completely with adding capacitance. Trust me we already tried that. Adding capacitance can work sometimes but sometimes it can also make things worse. It is not necessary that it will always improve dynamics, slam and transparency. The only way how to solve this was adding a second half bridge class d module to the 3800 watt power supply and putting the second module out of phase or bridging both half bridge class d modules. When doing this the bass performance was immediately improved and was the same as with the smaller 1200 watt power supply.

I'm a professional mastering and mixing engineer for the last 21 years. I have a very very trained ear since I use my ears for living my whole career. I am trained to use my ears to hear the slightest change in eq, compression, volume, distortion etc.... I always trust my ears first when auditioning audio gear and this is how I always start evaluating audio gear. After I make the listening evaluation I use high precision Audio Analysers for measurements and I also use a high precision measurement microphone so that I can measure the actual response from the speakers. I don't rely purely on measurements at all. Measurements are just a tool and just one of the aspects when designing audio gear. My first and most important tools are my ears. But measurements come handy especialy when fine matching stereo channels and when trying out different passive components or identifying a problem in an electronic circuit.

There are lots of DAC's, preamps, amplifiers I have came across that measure the same or almost identical. Do they sound the same? Of course not.

"All connections degrade the sound."

I would not fully agree with this statement. I would like to share my opinion and findings. For instance the JST connectors used for mains power on the power supplies and for the main rails are very high quality. We have tried soldering the wire direct to the power supply and it made no audible difference. I could not hear any improvement or difference. Soldering the wire right into the board for the main DC voltage rails that go from the power supply to the class d amplifier module also made no audible difference. The only difference that I heard and was also measurable was soldering the speaker wire to the amplifier board. But let me explain why we have decided to crimp the wire to the connector in our PNC1200 on the amplifier module side. We use a 12AWG occ copper wire with added 18AWG pure silver wire. The 12AWG occ copper wire outperformed a 14AWG occ copper wire in our test hands down. The 12AWG occ copper wire just has more body and weight to the sound. This is the reason we have chosen to use the 12AWG copper wire instead of 14AWG. The drawback with using 12AWG is that we can not solder the wire directly to the amplifier board. The wire is just to thick to fit in the holes after the JST speaker output connector is removed from the amplifier board. I compared two PNC1200 prototype setups. One had a 14AWG copper + 18AWG silver wire soldered to the amplifier module and the other had 12AWG copper + 18AWG wire crimped like in our final version of the PNC1200. In the listening sessions the 12AWG + 18AWG setup outperformed the 14AWG + 18AWG setup hands down. Again the results were more body and weight to the sound. We found a great balance with all components in our PNC1200 so this is one of the reasons why our PNC1200 amplifiers got so popular and are sounding this good.

This is the problem with silver.....almost always has a "silver sheen".

The reason why we have chosen to use the pure silver was that the WBT pure silver binding posts simply sounded the best from all the binding posts we have auditioned. Like you probably know silver is a better conductor than copper. In our testing phase we have tried all kinds of binding posts from Furutech, WBT, ETI, Cardas, Audio note etc... The WBT 0703AG pure silver binding post beat them all. It sounded just as good as pure wire with no coloration or added artefacts. Just should give these binding posts a try. They are really really good. They are expensive but worth the price.

My findings with adding a pure silver 18AWG silver wire to the 12AWG are as follows. When adding the pure silver wire to the 12AWG occ copper wire we achieved more detailed and smoother highs. I believe that it is not a "silver sheen" or some "character" added by the silver but more detail in my opinion. The result is crystal clear and smooth highs. Most very very expensive speakers cables use a combination of pure occ copper and pure silver as well.

The regulators and super output caps should be right next to the input stage.

The regulators and caps are very close to the input stage in most of our builds. Speaking of Sparkos regulators, they are very good. But I must share a great finding. We tried two LT3045 in parallel and two LT3094 in parallel and by surprise they outperformed the Sparkos regulators sound wise and they measure a bit better as well. Maybe we will use the LT3045 and LT3094 in the future instead of Sparkos regulators.

Having a bunch of connectors in series with this power supply distorts the sound, as well.

I'm sorry but I can't agree with this statement. Harmonic distortion is audible and also measurable. Very precise Audio Analyzers come very handy in this case. Even the slightest change in harmonic distortion would be visible in measurements. I use the ATC SCM 150 as my surgical tool. They are not the most enjoyable speakers that I have listened to but they are the most surgical and precise speakers that I have come across. They have ATC's SL drivers that are known as one of the lowest distortion drivers on the market. Even the slightest distortion in the audio material or in the audio chain is very very audible on these speakers. I hear no added distortion because of the connectors and I also can't measure any change in harmonic distortion. We have made tons of test over the time. For instance if our PNC1200 harmonic distoriton measurement is 0.0005% THD+N by default, this harmonic distortion doesn't drop with soldering the mains power cable direct to the power supply etc...

As for customisations like adding a Furutech mains inlet or similar we are always open to do such customisation if a customer desires this.

If you crimp wires in the AC power and use extra connectors then you degrade the sound.

I disagree as I can't hear no difference or measure it.

If you use a soft start, then you degrade the sound.

We don't use an additional soft start module in our amps. We use the soft start feature that is built in the Hypex smps power supplies. The AC MAINS inlet is connected direct to the splitter on our control board and from the splitter to the power supply. There are no additional soft start modules in between. The front button on our amps is just for controlling the standby mode. The only mains switch is on the back at the AC mains inlet. Like I've mentioned before, this can be customised if a customer desires it.

Hi Tibor,
May I ask you a few questions about your Apollon Audio mono amps?
I notice from your website that the PNC2K mono amp (nCore NC2K module) is more expansive than the PNC1200 mono amp (Purifi module).

Does the price difference reflect only their power output difference?
Or that the PNC2K mono amp having better sonic performance in other aspects too?
Or the vice versa?

And how about the nCore NC2K compared with other nCore power modules?
Is it having better sonic performance in other aspects too, instead of being only more powerful?

Many thanks for your advice in advance!

 

[Apollon]

Hi Tibor,
May I ask you a few questions about your Apollon Audio mono amps?
I notice from your website that the PNC2K mono amp (nCore NC2K module) is more expansive than the PNC1200 mono amp (Purifi module).

Does the price difference reflect only their power output difference?
Or that the PNC2K mono amp having better sonic performance in other aspects too?
Or the vice versa?

And how about the nCore NC2K compared with other nCore power modules?
Is it having better sonic performance in other aspects too, instead of being only more powerful?

Many thanks for your advice in advance!

Hello,

the price difference between the PNC2K and PNC1200 is purely based on larger enclosures of the PNC2K and more expensive NC2K modules that produce more power.

The PNC1200 has a bit lower harmonic distortion and sounds better in my opinion while the PNC2K is quite close sound wise to the PNC1200 but it has way more power. If so much power is required than the PNC2K is a better option.

The PNC1200 is based around the Ncore NC1200 module and not Purifi. In my opinion this is still the best performing class d module on the market. The harmonic distortion is almost as low as with Purifi but the NC1200 has a lot higher damping factor and way more power. It controls larger speakers quite better than Purifi. It just has more weight to the sound compared to Purifi. Especially on larger speakers.

 

[CKKeung]

Hello,

the price difference between the PNC2K and PNC1200 is purely based on larger enclosures of the PNC2K and more expensive NC2K modules that produce more power.

The PNC1200 has a bit lower harmonic distortion and sounds better in my opinion while the PNC2K is quite close sound wise to the PNC1200 but it has way more power. If so much power is required than the PNC2K is a better option.

The PNC1200 is based around the Ncore NC1200 module and not Purifi. In my opinion this is still the best performing class d module on the market. The harmonic distortion is almost as low as with Purifi but the NC1200 has a lot higher damping factor and way more power. It controls larger speakers quite better than Purifi. It just has more weight to the sound compared to Purifi. Especially on larger speakers.

Thanks Tibor!

And looking forward to the implementation of LT3045 x2 and LLT3094 x2 in your Apollon products.

 

[Loheswaran]

I don't want to antagonise, but have any of the amps using purifi or indeeed hypex units lost that kind of hollow sound? Thats where both solid state and tubes are good the ability to give body to the sound.
HAs this beeen genuinely overcome?

 

[Ric Schultz]

"I found that the Eigentakt was not only powerful enough to drive the A1s -- it sounded as good as the Constellations. As I wrote in my review, “almost nothing about the A1s’ sound had changed -- the tonal balance was the same, the highs were just as extended and the midrange just as pure, voices were equally robust, bass just as extended, and the soundstaging and imaging were exactly as before.” What’s more, I also thought that if there were any differences in the sounds, they “were at best slight and, surprisingly, favored the Purifi.” I played “Hope Is a Dangerous Thing for a Woman Like Me to Have -- But I Have It,” from Lana Del Rey’s Norman Fucking Rockwell! (16-bit/44.1kHz FLAC, Interscope). As I also said in the review, “the subtle sounds of her lips moving as she sings softly into the microphone were more apparent through the Purifi.” Ever since the arrival of the Revelation Taurus monos, I’ve loved their combination of smoothness, detail, and effortlessness -- for the Eigentakt to turn in the same performance, at a fraction of the price, was incredible. I was impressed. Granted, if I’d needed more power than the Eigentakt could provide, the Constellations would have easily walked away with the prize -- but in this first test, and within the Eigentakt’s power limitations, its sound quality had proved extraordinary."

The above is a quote from:

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

If you think the Constellation mono blocks he is referring to have no hollow sound.....then indeed....the stock Evaluation module amp mentioned in the above review (very similar to the $900 basic Purifi amp from VTV) has no "hollow sound".

Most class D amps until about 3 years ago had some of what you describe. You can change the sound of class D any number of ways....it is not just the module but every single thing you do. I can make a Purifi amp sound as hollow as you like.....or not hollow....warm and fuzzy or super analytical. This game is infinite. No module by itself is going to make great sound. The stock evaluator board amp or the basic VTV amp sound incredible for the money.......but when modded......that is another whole level better. Then there will be better circuits down the road. There is no end for this. Class A has been done at the serious level since the early 80s......class D has been done at the serious level for about 3 years.....there is a lot more coming.....yet these relatively inexpensive Purifi or NC1200 modded things are simply out of this world......but out of this cosmos is coming.

Some Class A amps are actually warmer than real, especially tube amps. Does any class D have as much "meat on the bones" as these warm sounding tube and Pass labs amps? I personally want my music to sound as rich and meaty as it was live.....not any more. So I design for as little signature as possible. However, if you have a lean sounding system....then you need a warm sounding thang in there to balance it out. Of course, you can use warmer Cardas, etc. cables to balance things out too. One thing is for certain. The distortion of class D amps is going down, down and down.......revealing more information......this is good. There will be plenty of class D amps in the future to pic from....some will even be designed to sound warm. In fact, VTV has just released a tube front end for the Purifi and Ncore modules to give you that WARM TUBE loveliness.

https://vtvamplifier.com/product/vtv-amplifier-custom-vacuum-tube-input-buffer-new/

 

[CKKeung]

In fact, VTV has just released a tube front end for the Purifi and Ncore modules to give you that WARM TUBE loveliness.
https://vtvamplifier.com/product/vtv-amplifier-custom-vacuum-tube-input-buffer-new/

Interesting & well-built tube buffer board.
However it's not cheap!

 

[Loheswaran]

"I found that the Eigentakt was not only powerful enough to drive the A1s -- it sounded as good as the Constellations. As I wrote in my review, “almost nothing about the A1s’ sound had changed -- the tonal balance was the same, the highs were just as extended and the midrange just as pure, voices were equally robust, bass just as extended, and the soundstaging and imaging were exactly as before.” What’s more, I also thought that if there were any differences in the sounds, they “were at best slight and, surprisingly, favored the Purifi.” I played “Hope Is a Dangerous Thing for a Woman Like Me to Have -- But I Have It,” from Lana Del Rey’s Norman Fucking Rockwell! (16-bit/44.1kHz FLAC, Interscope). As I also said in the review, “the subtle sounds of her lips moving as she sings softly into the microphone were more apparent through the Purifi.” Ever since the arrival of the Revelation Taurus monos, I’ve loved their combination of smoothness, detail, and effortlessness -- for the Eigentakt to turn in the same performance, at a fraction of the price, was incredible. I was impressed. Granted, if I’d needed more power than the Eigentakt could provide, the Constellations would have easily walked away with the prize -- but in this first test, and within the Eigentakt’s power limitations, its sound quality had proved extraordinary."

The above is a quote from:

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

If you think the Constellation mono blocks he is referring to have no hollow sound.....then indeed....the stock Evaluation module amp mentioned in the above review (very similar to the $900 basic Purifi amp from VTV) has no "hollow sound".

Most class D amps until about 3 years ago had some of what you describe. You can change the sound of class D any number of ways....it is not just the module but every single thing you do. I can make a Purifi amp sound as hollow as you like.....or not hollow....warm and fuzzy or super analytical. This game is infinite. No module by itself is going to make great sound. The stock evaluator board amp or the basic VTV amp sound incredible for the money.......but when modded......that is another whole level better. Then there will be better circuits down the road. There is no end for this. Class A has been done at the serious level since the early 80s......class D has been done at the serious level for about 3 years.....there is a lot more coming.....yet these relatively inexpensive Purifi or NC1200 modded things are simply out of this world......but out of this cosmos is coming.

Some Class A amps are actually warmer than real, especially tube amps. Does any class D have as much "meat on the bones" as these warm sounding tube and Pass labs amps? I personally want my music to sound as rich and meaty as it was live.....not any more. So I design for as little signature as possible. However, if you have a lean sounding system....then you need a warm sounding thang in there to balance it out. Of course, you can use warmer Cardas, etc. cables to balance things out too. One thing is for certain. The distortion of class D amps is going down, down and down.......revealing more information......this is good. There will be plenty of class D amps in the future to pic from....some will even be designed to sound warm. In fact, VTV has just released a tube front end for the Purifi and Ncore modules to give you that WARM TUBE loveliness.

https://vtvamplifier.com/product/vtv-amplifier-custom-vacuum-tube-input-buffer-new/

Hi Ric

Thanks for thee detailed and considered answer.
I am curious as to when and why you think Class D is going 'cosmic' soon?

I do think it is the way forward in the long run - just don't know when to jump as I am very fond of my LAvardin IT...

 

[CKKeung]

This ATM Audio RPM-700 monoblock is interesting.



This review is worth reading :
https://www.hifi-advice.com/blog/re...plifier-with-korg-nutube-triode-input-buffer/

It was said to resemble class A or A/B poweramps.
Yes, the chassis looks excellent but the Hypex 500 module and switching psu are the usual varieties.



Can the superior performance due to ATM's proprietary input circuit board ans the unusual Korg Nutube Triode Buffer module?

 

[CKKeung]

ATM Audio Korg Nutube Buffer for Purifi and Hypex NC500 :
https://atm-audio.com/product/buffer-korg-nutube/

 

[CKKeung]

NAD M33 on Stereophile :
https://www.stereophile.com/content/nad-masters-series-m33-streaming-integrated-amplifier

 

[KyoichiOda]

I would like to introduce another NCore amplifier, Ause Audio Equipment in Japan.

They had NC500 monoblock WF-P500, with their original noise reduction technology.

https://ause-audio.com/?page_id=1321

Unfortunately this nice model has been discontinued, however new budget NC500 model, WF-P502L is coming:



I tried it yesterday at their place, this is the best NC500 power amp I have ever listened especially detailed tonality.


I also listened NC1200 trial version which sounds superior at mid range and base with better attack.


They also have another unique product, WATERFALL Integrated 250, AK4497 DAC + NC250 power amp. This model has four working modes: DAC mode, Power amp mode, Integrated mode and outer preamp mode.

https://ause-audio.com/?page_id=1272

I realized at discussing with them that they have very original and unique idea. For example, they are planing a new product called "Digital Reconstructor", a sort of DDC but this feature has never seen before. I will report it in another thread.