Rogue Audio Pharaoh II integrated amplifier

This morning, I received an email from John, my DIY friend in Europe, saying how happy he was. He had just finished building a new power amplifier using two UcD250LP class-D amplifier modules. He described the results as "quiet, clear, clean, effortless class-D power," adding, "What more could I ask for?"

I am slow on the uptake, so I thought my friend's question was sincere, not rhetorical. Moments later it hit me: This is a question I should try to answer in this review of the Rogue Audio Pharaoh II amplifier. Beyond the virtues John described, what more, indeed, could we ask for?

In closing, John mentioned, "Later, I might build a tube input buffer for it, but for now I am happy."

My Euro friend's letter reminded me that in last month's Audio-GD DAC review, I speculated that most digital designers are probably trying to make their DACs sound like analog. (I mean, duh! What's the alternative?) Then, this month, as I installed the Pharaoh II tube–class-D hybrid amplifier, I wondered: How many class-D amplifier designers are trying to make their small, light, cool-running amps sound like hot, heavy, high-power class-A amps? Or like glowing tubes?

That vein of thinking led to another question: What is it I relish in class-A amplifiers that I don't get from class-D amplifiers? And what about triode tubes? Why is their effect so mesmerizing?

My answer to the class-A question is, first and foremost, that I always want amplifiers driving my speakers to deliver a natural, lifelike tone; anyone should be able to hear it. Instruments, voices, and recording studio effects should sound conspicuously like themselves. Natural tone is the trait I seek above all, in all audio gear, but it is not the first trait that comes to mind when I think of class-D, which I primarily associate with slam, deep bass, and paranormal clarity.

Along with natural tone, class-A amps specialize in recovering the microdetail and nanotextures that inhabit every recording at low signal levels but that other classes of amplification (B, AB, C, D) miss. The first time one experiences thick, rich, heavy class-A, its breathy atmospheric data might seem foggy or even distorted. Because of that, I think some audiophiles mistakenly associate "clean and empty" sound with "transparent and undistorted." To those listeners, the stark clarity of class-D must be appealing. I am (pun intended) biased toward class-A, but I am also drawn to and impressed by class-D because I think it sounds clearer, better-sorted, and more appealing than steerage-class AB.

I once spent time with a class-D amplifier that didn't sound class-D clear. Instead, it sounded dark, foggy, and atmospheric in a manner that suggested that its designer (another friend) was trying to spritz some class-A spice into those class-D voids. Maybe my DIY friend should be seeking the transmission of more information: more teeny, tiny notes and sparkling nano-energy to fill the spaces after class-D's famously firm transient attack; more dense energy in the sustain and more touchable textures in the decay. That's what I decided to seek in this review of the Rogue Pharaoh II amplifier.

1222rogue.ins

Description
For the Pharaoh II, Rogue's founder and chief engineer, Mark O'Brien, opted to replace the original Pharaoh's Hypex UcD400 module with Hypex's slightly more powerful and, to my ears, cleaner and more relaxed-sounding NCore NC500 module. (The Sphinx V3 uses the UcD180.)

According to Mark, "The NCore modules are different than the UcD modules in terms of power supply requirements as well as needing an independent buffer stage, which is included in the UcD400 package. Since we generally design our own buffer stages, this allowed us to simplify some aspects of the original design and achieve a higher level of performance.

"The NCore modules require higher operating voltages for the B+ rails as well as an additional supply voltage for the driver stage of the module. Consequently, the power transformer in the Pharaoh II is 20% larger than in the old Pharaoh. We use strictly large, linear power supplies rather than switching supplies in our hybrid amplifiers. My experience has been that the sometimes-edgy sound of solid state and particularly class-D amplifiers may be a result of using switching power supplies in the design. While they allow for smaller amps and are less expensive, switching supplies just don't seem to sound as good. I would point out to your readers that when they are listening to an amplifier, they are effectively listening to the power supply being modulated by the audio signal. I can't overemphasize the importance of good power-supply design. "The power transformers—there are two—are both toroidal designs, for low noise. Stray noise is always a challenge in integrated amps because you are forced to locate electrically noisy components (eg, transformers) near noise-sensitive areas, such as a phono section.

"The power supply for the mu-follower preamp is quite straightforward and consists of a string of RC Pi filters that are large enough to swamp any AC ripple as well as decouple the two channels from each other. The 12AU7 preamp tubes are run at a very low current, so they don't require much in the way of storage capacity. There are also separate regulated supplies for the heater filaments in each tube. Isolating heater supplies may contribute to lower noise and greater channel separation.

"The new Pharaoh was designed on a CAD system that we installed not long after the first Pharaoh came out back in 2015. This new platform allows us to create more complex designs with better grounding and tighter traces. This gives us cleaner circuit layouts, which in turn result in a lower noise floor and better performance. We also completely redesigned the headphone circuit and updated the phono section.

"The phono section uses three Texas Instruments OPA2134 dual op-amps. These new op-amps pretty well outperform discrete devices and have extremely low noise figures. They use a JFET input and are designed specifically for use in high-end audio.

"I pretty much always use passive RIAA equalization in our phono sections, as is the case in the Pharaoh.

"The signal for the headphone circuit is taken directly from the tubes and then fed into a pair of MOSFET buffers to lower the output impedance to close to nothing. It puts out about 1.5Wpc and will drive most headphones."

Unlike ancient Egypt's, Rogue's Pharaoh is larger than its Sphinx. According to the owner's manual and Rogue's website, the Pharaoh II is built entirely in the USA. It measures 18.3" wide, 6.5" high, and 18" deep and weighs 39lb. Rogue rates the Pharaoh II at 250Wpc into 8 ohms and 400Wpc into 4 ohms. Its input sensitivity is 1.0V RMS (for full power), and it draws 10W from the wall on standby, 1065W at full power. Its damping factor is said to be >1000.

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The Pharaoh II's back panel includes three single-ended (RCA) line-level inputs, a unity gain input (RCA), and a balanced input featuring Neutrik XLR sockets. On the far left is an RCA phono input with internally adjustable gain (40dB or 63dB) and MC cartridge loading of 20, 75, 100, 230, 300, 1k, and 47k ohms. There are two preamp-level outputs on RCA—one fixed, one variable—and a tape loop for the 21st century: processor in and processor out. Finally, there's the usual loudspeaker binding posts and IEC socket.

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The Pharaoh's front panel may be ordered in black or silver brushed aluminum. With either choice, the knobs and buttons are silver and arranged in a bilateral symmetry, with a big power button on the far left mirrored by a headphone button of equal size on the far right. Inside Rogue's signature recessed oval are a medium-sized input-selector knob followed by a small processor-loop button, then the large, centered volume control, then a small unity-gain button, and a medium-sized balance knob. The sensor for the remote control on the far left is mirrored by a similar-looking hole for a 6.3mm headphone jack on the far right.

The top of the Pharaoh II's chassis features a 3.25" × 5.5" perforated vent that lets users see the two long-plated JJ ECC802S/12AU7 twin-triode tubes. These tubes, a tube-roller friend told me, are "not an unworthy successor" to the legendary Mullard and Telefunken long plates. What users can't see (without removing the cover) are the large (400VA) Antek toroidal transformer and the smaller Avel Lindberg toroid, the premium Nippon Chemi-Con electrolytic power-supply capacitors, and the German-made Mundorf aluminum and oil-coupling capacitors. All premium bits.

Listening
Rogue Audio's Pharaoh II entered my system on a Sunday morning. For the whole day, through both phono and line inputs, it sounded like a guitar string stretched too tight, ie, overdamped and out of tune. It showed not even a vague family resemblance to the Sphinx V3 I had been using for the two previous days. I chalked up the Pharaoh's tightly wound demeanor to its needing more time for its fancy transformers and capacitors to form.

COMPANY INFO
Rogue Audio Inc.
PO Box 1076
Brodheadsville, PA 18322
info@rogueaudio.com
(570) 992-9901
ARTICLE CONTENTS

COMMENTS
Glotz's picture

I really appreciate your personal insights on this as well as SET Tube-based amplification.

But what about single-ended transistor-based amps?

I've had my eye on the Audio By Van Alstine DVA-225 monos (SET), and I'd really like to put my ear on them sometime. Given their direct, custom order business model, it takes a bit more courage to audition.

I'm also searching out the Rogue hybrid power amps to feel them out as well.

I'd really like to see the market put out a GaN-based power amplifier for under $5k as well. I'm sure one day that will happen, given their burgeoning presence in the market now.

Very nice column as usual; I always feel like we know your brain and soul a bit more with every month's writing.

Happy Holidays to Herb and the rest of the Stereophile staff!

Herb Reichert's picture

My solid-state reference amplifier for use with the Falcon speakers is the Nelson Pass-designed First Watt F8; which is single-ended, and uses a touch of 'tidy-up' feedback.

To my way of looking, the F8, and its First Watt sibling, the J2 (also single-ended), and the SIT-3 are among the most innovative amp designs of this era.

In audio we must always champion innovation and engineering diversity. If we don't, the listening party is over.

hr

Jack L's picture

Hi

Indeed.

F8 employs current feedback intead of voltage feedback used in J2.

As Nelson Pass said: "I enjoy amplifiers with a little personality",
the power output coupling capacitors he used are "2 big electrolytic & one PP capacitor with a roll-off of 1Hz."

All capacitors get their own "personality" sound qualtiy. The last type of caps I would ever use for music signal coupling is electrolytic due to its complex dissipation factor & ESR etc etc due to its dielectric used. Not sooo good sounding at all.

For F8 $4,000 selling price, Nelson could have used better sounding coupling capacitors than electrolyitic.

FYI, I don't even electrolytic capacitors for power supply ripple filter caps for its sonic issue. I've used motor-run OIL capacitors instead !

Listening is believing

Jack L

georgehifi's picture

JA:"The Pharaoh II's reproduction of a 10kHz squarewave (fig.2) showed only the slightest hint of overshoot, with no ringing."

Is this the reason there is no hint of overshoot, because you can't see it when it's measured at low level + - 1v output, with the AUX-0025 bench testing filter installed on the amps output?

Cheers George

John Atkinson's picture
georgehifi wrote:
JA:"The Pharaoh II's reproduction of a 10kHz squarewave (fig.2) showed only the slightest hint of overshoot, with no ringing."

Is this the reason there is no hint of overshoot, because you can't see it when it's measured at low level + - 1v output, with the AUX-0025 bench testing filter installed on the amps output?

No. You can see from the frequency response curves in fig.1, which were taken without the auxiliary filter, that the Rogue's output rolls off smoothly above the audioband into higher impedances. There is is only a hint of an ultrasonic peak into 2 ohms (green trace).

John Atkinson
Technical Editor, Stereophile

georgehifi's picture

that's odd

John Atkinson's picture
georgehifi wrote:
Sorry JA, I beg to differ, maybe you forgot the AUX-0025 was used to do the square wave shots.

I didn't forget. But without the AP auxiliary filter the squarewave response is obscured by the ultrasonic noise that I mentioned in the measurements. That is why I use the filter for the published 10kHz squarewave. The filter removes the ultrasonic noise without significantly affecting the shape of the waveform.

I don't use the filter for the frequency response measurement as I want to see the actual behavior of the class-D amplifier's own low-pass filter. The Rogue amplifier's filter is well-behaved, with the shape of the ultrasonic rolloff correlating with the squarewave response.

georgehifi wrote:
As the response curves and square waves shots look the same and level for all other Hypex NC500 equipped amps you've measured but stated you used the AP AUX-0025 on their outputs still at the same + - 1v. (why measure the Rogue' square wave output at only 1vpp if the AUX-0025 wasn't used?)

The frequency response and squarewaves I publish in amplifier reviews all show the small-signal behavior, ie, the amplifier is operating at an output level where it is linear. The level of the squarewave doesn't affect its shape.

Note, BTW, that the scaling on fig.2 is arbitrary, as the digital 'scope is being fed from the Audio Precision SYS2722's Monitor output. It is not the actual level I use for this measurement, which was actually 2W into 8 ohms.

John Atkinson
Technical Editor, Stereophile

windansea's picture

I enjoyed Herb's ruminations on Class A and D (which he's discussed in other reviews). I have both types of amps, as well as a 12AU7 based preamp, so this review really spoke to me. I imagine that a NOS tube would sound even nicer in the Rogue than the JJ tubes. As long as you're spending a few grand, spring for some Siemens or Telefunken or bugle boys.

Now that the weather has gotten a bit chilly where I live, I brought my "winter amp" (Class A) out to the living room where the wasted heat is welcome for 3 months.

A technical question: does it really matter for an ncore unit if it's a switching power supply or a toroidal? I've heard that switchers might have more EMI, but a regular transformer has ripple that needs to be tamed by caps and chokes. I think we can stipulate that linear is simpler and thus more reliable.

Jack L's picture

Hi

Yes, NOS or old Telefunken or even made-in-UK new Mullards would sound better than JJ tubes. I used both for my design/built phono-preamp !

BUT from pure technical viewpoint of designing Mu-Follower which is used in the Rogue integrated amp, I would NOT used ECC82/12AU7 which got too much Mu for the lower half of the twin triode which would work not sooo stable in the event of the operating plate voltage drop due to power surge etc.

The much better twin-triode I would recommend is ECC81/12AT7 which get good gm but not too high Mu & still works stably in the event of plate voltage drop for whatever HVPS issues.

Yes, Mu-Follower is efficient & high gain & gets super lower harmonic distortion provided it is NEVER overdriven to clipping !!!! Once overdriven, it produdces tons of even & odd harmonic BLOCKING distortions considering the hi-gain op-amps are used for its RIAA phonostage !!!!!!!

I don't mind discuss the design issues of this Rogue amp with its whoever designers. For a bit more cost money using discrete devices, best using triodes, it would sound even much better, IMO.

Listening is believing

Jack L

MatthewT's picture

I'm interested in this amp, but am not willing to spend any money on it until you fix it for them.

"I don't mind discuss the design issues of this Rogue amp with its whoever designers."

Jack L's picture

.

MatthewT's picture

Pal.

georgehifi's picture

Yes it does to my ear, as I have the NC500's in mono-block form (used with no buffers) because my discrete R2R MSB dac (with volume control)and can put out enough bal volts direct into the NC500's for the loudest that I would ever listen to on my 89db speakers

And with Hypex's own SMP (switching supply) they had, while good, it could not equal the Linear Toroidal power supplies I substituted for them. Much less sterility and more body to the sound, the only place the SMP's equaled the linear supplies was in the bass slam, but again not for body detail. EG: double bass being bowed, both as taught as each other, but the gut of the bow comes through far better on the Linear Supply.
I'm all behind Rogue etc for using linear supplies for their Class-D Intergrated and power-amps, while much more expensive and using far more real estate they sound far better, if designed correctly.

Cheers George

windansea's picture

I've got one amp with NC1200 modules and maybe I'll try a linear power supply. My class A amp has a giant toroid and big caps-- wonder if I could divert that as an experiment. Time to call my electrical engineer buddy...

Jack L's picture

Hi

BINGO ! NEVER ever use any SMPS for any audio amps, period. It is a last stage of RFI/EMI cancer for any audio amps !

Any SMPS emits RF noises airborne & thru hardwiring into any powerlines associated with it. Any other audios plugged in the same & even remotedly connected powerlines in the same premises get in as free bonus.

Don't need any costly powerlines noise testers, like the wideband powerline noise analyzer I use all the time to test the RF noise there or not. Any AM radio will get extremely noisy when placed near any those SMPS wallwarts !

That said, I still use a SMPS wallwart to recharge the bias batteries for all the tubes inside my design/built SET power amp - convienient & cheap ! But surely the wallwart, plugged in a wall outlet totally detached from my audio rig dedicated powerlines.

For RFI/EMI noises, never take for granted !!!!!!

Jack L

PeterG's picture

Finally! A rave review of a Class D that does not ignore the elephant in the room--Class A. I love my tubes too much to switch, but it's great to see the new tech emerge. Thanks

georgehifi's picture

Hmmm! Please don't delete, comments are for debating + & -'s also.

Sorry JA,I have these NC500 modules here, and they vhf ring (just like this at only 1khz!! https://ibb.co/R2NPzHQ ) with (switching noise) with even 1khz let alone 10khz square wave on the scope without using a low power external AP AUX-9925 type filter or similar, as will/do any other amp that uses the NC500 modules.

Cheers George

georgehifi's picture

Submitted by Jack L: "Any SMPS emits RF noises airborne & thru hardwiring into any powerlines associated with it."

So true, all they achieve is more profit, as they are cheaper and take up less real estate than good Linear Supplies.

Cheap Test:
With an old portable transistor AM radio (that doesn't auto mute off channel)
Tune it down low 600khz-700khz off channel with the volume up and go near any smps with it, and hear what's bombarding your audio signal.

Cheers George

Jack L's picture

Hi

My small 33-years-young Panasonic pocket radio always tuned to 680KHz (our local gas price forcast channel) gets noisy like hell whenever placed near any plugged-in SMPS wallwart.

You can imagine same RF noises airborne into yr HIFi system - no execption !!!!

Any cheapie yet very effective way to safeguard yr HIFI from RF noise airborne invasion ???

Of course, there is. I already DIY-installed such anti-RFI devices to
ALL my audio components even including all my pure silver interconnects, power cords, loudspeaker cables etc etc etc. since day one.

Never befriend with RF/powerline nosies !!!!!

Jack L

windansea's picture

Benchmark Audio offers the contrary view:
google for full version:
AUDIO MYTH - "SWITCHING POWER SUPPLIES ARE NOISY"

THIS MYTH GOES SOMETHING LIKE THIS:
"Switching supplies are noisy."

"Linear power supplies are best for audio."

We disagree!

About 5 years ago, Benchmark stopped putting linear power supplies into our new products, and we replaced them with switching power supplies. We did this because linear supplies are too noisy. Yes, you read that correctly, linear supplies are noisy! A well-designed switching power supply can be much quieter than a linear supply.

LINEAR POWER SUPPLIES CAUSE HUM
The noise problem is due to the fact that linear power supplies have large transformers and other magnetic components that operate at the AC line frequency (50 Hz to 60 Hz). These line frequencies are audible, and we are all too familiar with the hum and buzz that audio products can produce. It is no secret that this noise is caused by the power supply, but few people understand why it can be so hard to eliminate. Most people think that hum is caused by conducted interference (AC ripple on the power supply rails), but this is rarely the case. Most AC hum is caused by magnetic interference, and this can be very hard to eliminate.

HUM IS USUALLY CAUSED BY MAGNETIC INTERFERENCE
Transformers are magnetic devices. Power is magnetically transmitted between a transformer's input and output windings. In a linear supply, power is transmitted from the AC line side of a transformer to the low-voltage secondary side using an AC line-frequency magnetic field. Unfortunately, transformers are never perfect, and some energy always escapes through stray magnetic fields. These stray fields can interfere with virtually every electrical conductor in an audio product. Magnetic shielding is expensive and it has limited effectiveness when sensitive circuits are located in close proximity to a strong field.

POWER AMPLIFIERS ARE THE WORST OFFENDERS
The power supplies in high power devices, such as audio power amplifiers, can emit very strong magnetic fields. These strong fields tend to limit the noise performance (SNR) of power amplifiers. These magnetic fields can also cause interference with audio products that happen to be too near the amplifier. Audio cables that enter, exit, or pass near the amplifier may also pick up unwanted hum and buzz. For this reason, it is usually very important to keep the power amplifier well separated from cables and other components in the audio system.

BREAKING ALL THE RULES!
Benchmark's new AHB2 power amplifier breaks the rules. It can even be located adjacent to sensitive audio components without causing interference! The AHB2 is a high-power device, but it emits almost no magnetic interference. What makes it different?

The secret inside the AHB2 is the switching power supply. This power supply has several high-power transformers, but they are very small, and their stray magnetic fields are correspondingly small. The reason for this is that the magnetics operate at 200 kHz to 500 kHz. For a given power rating, transformer size decreases as the operating frequency increases. High-frequency transformers have smaller cores and fewer turns of wire. As the physical size decreases, there is a corresponding reduction in stray magnetic field strength.

SIZE MATTERS
When transformers are physically small, there are more options for magnetic shielding. For example, the small transformers used in the AHB2 are completely encased in a ferrite material which helps to contain stray magnetics. These techniques are so effective that the AHB2 achieves a SNR of 130 to 135 dB. No power amplifier is quieter than the AHB2. Even more amazing is the fact that the switching power supply board is less than an inch above the amplifier board. This product proves that switching power supplies can be very quiet! The AHB2 could not achieve this level of performance with a linear supply unless the supply were housed in a completely separate box a couple of feet away.

OUT-OF-BAND NOISE
One major advantage of switching supplies is that the operating frequency is above the range of human hearing. If interference occurs, it will not cause audible interference. This interference can even be removed with a filter without infringing on the audio band. But, the power supply in the AHB2 is so quiet that we do not need to filter the audio output. The AHB2 delivers a 200 kHz bandwidth without evidence of any significant switching noise, to a measurement limit of 500 kHz.

LINEAR AMPLIFICATION WITH SWITCHING SUPPLIES
Please note that the AHB2 is not a class-D switching amplifier. The AHB2 is a linear class-AB amplifier. It is only the power supplies that operate in a switched mode. The power supplies simply provide steady and constant regulated DC voltages for the linear audio amplifier.

MatthewT's picture

They didn't consult Jack.

Jack L's picture

.

MatthewT's picture

To defend your argument. So far you know more than Rogue and Nelson Pass. Go for the trifecta and add Benchmark?

Jack L's picture

HI

Anybody knows the basic of Switched-Mode Power Supply (SMPS) will disagree what Benchmark reportely stated per your above post!

Instead of standard linear power supply rectifying the grid power (50/60Hz) to DC, SMPS generates the required power by switching a tuning coil at a very high frequency (from many hundred KHz to many mega Hz) & then rectified it to DC. Such HF switching produces a rippling voltage with high harmonics = electromagnetic interference EMI which is transmitted in the air & pass out via direct wiring, e.g. via its power cord.

There why when you open up any SMPS, you will always see a metal cover to cover up the switching electronics therein to shield off the airborne EMI, & a low-pass filter comprising coil(s), capacitor(s) to filter off the EMI from going out the SMPS with the rectified DC.

The problem is it is indeed a big deal to contain the EMI effectively inside the SMPS. In fact SMPS for commercial application are required to have their own very effective EMI suppression in order to be allowed to be usesd without affecting the existing electrical/electronic establishment.

Airborne EMI: a small battery-powered AM radio easliy detects airborne EMI from a working SMPS wallwart, like cellphone/tablet charger & the like. The radio get very noisy when placed nearby the wallwart !!

Powerline EMI: take an common example of any CD/DVD player which most most, if not all, come with built-in SMPS. Whenever the player is switched on, the built-in SMPS discharge EMI into the wallout/powerline which I detect without fail in my brandname wideband powerline & EMI noise digital analyzer.

Yes, SMPS is extremely power efficient up to 95%, stable output voltage & current (provided not overloaded!!) & compact in size relative to standard linear power supplies. BUT its EMI is hard to control!!

"Out-of-band" noises

EMI intermodulation products, 2nd, 3rd..orders of the switching frequency & its HARMONICS can go into the audio spectrum. Sensitve ears can find such intermoduations much more annoying than normal harmonic distortion due to the characteristic of our auditory system.

That's why. taking the example of a brandname powerline filters (made-in England), which I installed in the dedicated powerlines for my audio rig, are super wideband: 20KHz - 100MHz & way way beyond to GHz (out of the bandwidth chart) with max insertion loss of 52dB @ 32MhZ & 35dB @ 100MHz. This would cover EMI noises from any UPS & cellphones (1GHz - 6GHz+++).

Yes, standard linear power supplies do get 50/60Hz hum noise, which can be reduced to be ear inperceptible if done properly. But such noise is ear friendly vs EMI intermoduation products can sound from annoying to irritating.

YES, SMPS with really efficient (but costly) EMI suppression can measure superb but stil can NOT match the ear-friendly analogue noise produced by standard linear power supplies in music reproduction.

SMPS may win the noise-level battle but lose the war musically !!!!

Listening is believing

Jack L

windansea's picture

Please explain further how the intermodulation distortion of extremely high frequencies can get back into the audible spectrum? You may have a point there but I don't get it. Aren't the harmonics happening at even higher inaudible frequencies? And therefore doesn't the low-pass filter cut these off from reaching the listener?

Also, Benchmark made a point about magnetic interference from linear supplies. Any reply to that? Personally I can't stand any hum. I had hum with a Jolia amp two decades ago, found it intolerable for hifi. My current systems (SET, tube pre, Pass class A, nCore class D) all have zero hum and that's a top priority for me.

Jack L's picture

...... can get back into the audible spectrum?" qtd windansea.

Hi

Michael Fremer commented on the same question you just asked in his review of Yunyata Denali power conditioners:
"But Shunyata doesn't explain how noise at a frequency of 1MHz can affect the audioband (20Hz–20kHz)."

So let me do the explanation:-

The intermodulation products are spurious frequency components generated when two or more signals pass through a non-linear device. The intermodulation products can be of different orders, such as second-order or third-order, depending on the non-linearity, number, and frequency of signals present in the system.

For SMPS, the high orders of harmonics generated with the switching frequency spread over pretty wideband frequency spectrum down to audio range.

The low-pass filteres inside a SMPS, if done properly, should remove any EMI noise from the DC coming out from the SMPS. As I already said above,
SMPS for commercial use MUST equipped with EFFECIVE EMI suppressors in order to be allowed to use in commercial establishsements.

For for audio amps & other digital gear, e.g. CD/DVD/DAC etc, the built-in EMI filters may not be effective enough to do the job right. That's why I can detect such EMI discharged from the SMPS into the powerlines with my EMI analyzer.

As I already said in my above post, the 50/60Hz hum noise & the magnetic flux leakage from the power transformers can be eliminated beyond ear perception if done properly. But such noise is analogue, friendly to our ears vs EMI noise annoys or even irritates our ears due to the chararteristics of our auditory system.

My design/build TUBE phono-preamp & SET power amp & my upgraded brandname tube phono-preamp & tube power amp got no audible hum at all.

Please read between the lines to differentiate sales pitch from electrical physics !!

Listening to analogue is believing

Jack L

tenorman's picture

Dear Jack ,
Overview. Grandiose Narcissistic personality disorder is a mental health condition in which people have an unreasonably high sense of their own importance. They tend to brag and be elitist .Those with grandiose narcissism are arrogant , aggressive, dominant and exaggerate their importance.

Jack L's picture

Hi

Don't need to throw me such mentality terminology! Sourgrapes !

KNOWLEDGE is the power of domination!

Lack of knolwedge will dwarf whoever into inferiority complex.

My question to YOU: do you own the audio knowedge needed to show your domination here ???????

How many post(s) of yours in audio technology, if any at all, ever got published in Stereophile journal??? Show us, please.

If you don't got any here at at all, please learn such audio technology knowedge before you stick your head out to be chopped literally.

You are more than welcome to show off your audio electronic knowledge provided you really got it !!!

I am all eyes !

Jack L

Jack L's picture

Hi

KNOWLEDG is the power of domination !

(Sorry, Mr. Editor, I am way out of audio here. Please bear with me. Thanks)

As an electrical engineer dealing in the electral power industries for decades in USA/Canada, audio electronics to me is a piece of cake !

Just show off to YOU my power of domination in electrical power engineering:-

Many many years back, a field engineer from a neigbour city power company called me up frantically for help in restoring electrical power to a regional blackout! He told me the VHV overhead transmission line was brown down by the snow storm. He needed miles of such particular overhead power like yesterday to reverse the blackout. The problem the power company engineer did not even know what cable was it exactly !

I requested a short piece of cut sample of the down powerline which arrived within one hour to my office.

On checking the over diameter & strand number of the cable, I made a phone call & within 2 days the miles of brandnew replacement powerline was thrown in by air & delivered to site !

Needless to say, I made excellent money for my employer for such emergency solution !

KNOWLEDGE is the power of domination !

Jack L

I

David Harper's picture

You described Trump perfectly.

stungun's picture

... particularly compared to the Sphinx v3. Wondering if that's because the Sphinx moved HR more in absolute terms, or if it is the combo of Sphinx sound and its value quotient that make it the more exciting product.

DrGregC's picture

The $64,000 question - How does the Pharaoh II sound compared to the original Pharaoh? In looking for the correct amp for my KEF LS-50's, I was surprised and blown-away when the dealer hooked-up the original Pharaoh. I always thought of it as a well-kept secret. Unlike his other products, Mark never tweaked or offered upgrades to the original since the introduction in 2015. Pretty good first effort. The model II is so different, that he doesn't offer an upgrade path. This review doesn't make me want to run out and buy the new version.

asherrick's picture

Greg,

The Pharaoh II is a substantial improvement over the original. Is it worth the upgrade cost from the original Pharaoh? That's a question only you can decide (and hopefully your dealer can help you by taking your amp on trade).

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