Mytek Brooklyn Amp power amplifier

Designed in New York City, manufactured in Poland, and barely bigger than a thick paperback, the Brooklyn Amp ($2495) is Mytek's first power amplifier. Like all of their products, it's sleek to behold, with a powerful look that suggests the company's pedigree: in addition to high-end consumer electronics, Mytek makes gear for the pro-audio market, where exceptional build quality and space-saving design are the norm.

Consistent with that last characteristic is the Brooklyn Amp's output architecture: it operates in class-D, a technology that remains controversial. In my first review for Stereophile, I evaluated the Spec RPA-W7EX Real-Sound class-D power amplifier ($5995). That hefty silver box warmed my cockles with sound that was worthy of comparison to that of tubed amplifiers: delicious spatial performance and tonality that thoroughly surprised me. The mighty Spec warranted superlatives I usually reserve for my Shindo Laboratory Haut-Brion, coming as close to that amp's humanness as one could wish for in a class-D amplifier.

The question: is class-D ready for prime time?

A demure beast designed in Brooklyn
Mytek occupies a former church in Greenpoint, Brooklyn—a building that, as recently as 2010, housed the studio of the artist Kehinde Wiley. From the street, the place looks like a crumbling homeless shelter. There I picked up not one but three Brooklyn Amps: the standard dual-mono stereo version, which produces 300Wpc; and two Amps set up in bridged mode, each working as a 600W monoblock. John Atkinson thought it made sense to listen to the Brooklyn Amp(s) hooked up to Mytek's Brooklyn DAC Plus ($2195), so I made space for one of those, too, in my ever-ready LP backpack.

818mytek.stack.jpg

Because, when in Greenpoint, record shopping is a must. This historically Polish neighborhood offers such vinyl hangs as Record Grouch, Academy Records Annex, The Thing, CO-OP 87, Captured Tracks, and, within a 10-minute walk to Williamsburg, Rough Trade. Excellent Polish bakeries abound, and Peter Pan Donut & Pastry Shop is an absolute treat. But I digress . . .

Deep below ground level, in the labyrinthine bowels of Mytek Central, is a fully operational recording studio. You know you're in a pro-audio space by the powerful air-conditioning system that bathes the studio in lovely freezing air. A smaller, well-isolated studio holds a control console, and two pairs of speakers: massive Duntech Sovereigns (90dB sensitivity), and the smaller Wilson Audio Specialties Sabrinas (87dB). Two Brooklyn Amps in bridged-mono mode were driving the former. Effortless dynamics pounced on me like two hungry tigers.

"Duntechs, with their multiple drivers and complicated crossovers, are a very difficult load," Mytek's chief designer, Michal Jurewicz, told me. "Hypex [class-D modules] cannot drive it, the amps collapse, but this Brooklyn Amp does it with ease. This came out during months of design tests I did in 2016, when we were testing many different circuits." Jurewicz also said that Mytek spent six months experimenting with more than 15 class-D amplifier modules from various OEMs, upgrading parts, adding capacitors, adjusting circuit parameters.

"Class-D is a relatively new technology, and there isn't yet enough consensus in correlating circuit properties vs subjective sound quality," Jurewicz wrote in response to my e-mailed questions. To get any such response, I had to use the journalistic equivalent of dentists' pliers. There's great competition among class-D designers, and the success of Mytek's DACs and preamps—not to mention their Brooklyn DAC+ being one of the first fully functional MQA-ready D/A converters—has put Jurewicz in the catbird seat. He'd rather not answer any questions. Trade secrets.

Though Mytek ultimately chose an amplifier module from the Danish company Pascal A/S, it's far from an off-the-shelf version. "We use one Pascal," Jurewicz wrote, "but the module is heavily modified. Major parts are replaced, and they don't sound anything like the originals (way better, more detailed and warmer). We've changed switching speeds, changed numerous parts in an attempt to significantly reduce distortion, and we beefed-up the power supplies. There are not really any classic transformers inside. It's all well-executed switching technology. That's why it's so small and light."

Inside and Out
Mytek's familiar logo, which looks to me like a backlit Rorschach ink blot, appears in the upper-left corner of the Brooklyn Amp's faceplate; a much larger version is formed by the ventilation holes punched in the top panel. The faceplate's textured surface reminds me of an optical illusion in which the pattern seems to float free of the surface when stared at long enough. On it are only a single power button with a feel that made me want to press it and keep pressing it. I resisted. After the Amp is powered off, that Rorschach jack-o'-lantern on the front panel glows faintly.

On the Amp's well-sorted, easily accessible hindquarters are: one pair each of gold-plated unbalanced (RCA) and balanced (XLR) analog input jacks, two pairs of large speaker binding posts, an IEC power inlet, a small jack for a 12V Power Up trigger, and a row of tiny DIP switches.

818mytek.bac.jpg

Two of the DIPs control gain (0dB up, +6dB down) and mode (balanced up, unbalanced down), and two others work together: "When #7 is up the AMP works in a regular stereo mode," notes the manual. "When #7 is down the AMP mode depends on dipswitch #8 setting; when #8 is up the AMP works in Bi-amp mode. When #8 is down the AMP works in a Bridge mode."

When he explained to me the inner workings of the Brooklyn Amp, Jurewicz cracked open its lid to reveal a dual-mono configuration: a tightly spaced row of eight oversize capacitors on each of two circuit boards, and some similarly large chokes. Unlike DACs or amplifiers whose impressively big cases are mostly empty, the Brooklyn Amp, which measures 8.5" wide by 1.73" high by 9.5" deep, leaves no part of its circuit boards unfilled.

Although the Amp's current owner's manual doesn't provide operating instructions, an updated version will be available soon online, Jurewicz said.

MacDougal Street Setup
In past reviews I've complained until you, dear reader, are no doubt tired of hearing about the treacherous climb to my penthouse pad, in the New York City sky. The four Myteks were together no heavier than two bags of overpriced groceries from our soon-to-be-razed local supermarket. Who needs food when there are luxury condos to build? Gotta house those new-money 30-year-olds somewhere.

I used the single stereo and the two bridged-mono Brooklyn Amps in both of my systems: the smaller rig of Thorens TD 124 turntable, Jelco TS-350S tonearm, Ortofon Quintet Bronze cartridge, and Quad S2 speakers; and my big rig of Kuzma Stabi S turntable with Stogi S tonearm and Hana EL cartridge, PS Audio NuWave DAC, LG Blu-ray player, and DeVore Fidelity Orangutan O/93 speakers.

Michal Jurewicz had loaned me a pair of Mytek Metropolis balanced interconnects to join DAC to Amps. Tellurium and Auditorium 23 speaker cables respectively snaked their ways into rigs small and big. TriodeWire Labs American interconnects also saw duty.

The Mytek Amps are small enough to fit anywhere, but when I placed one under the Brooklyn DAC+ in my small-rig rack, I was surprised when it ran relatively hot.

COMPANY INFO
Mytek
148 India Street
Brooklyn, NY 11222
(347) 384-2687
ARTICLE CONTENTS

COMMENTS
Bogolu Haranath's picture

"Watts are cheap" ........... Anonymous :-) ................

Those words are coming true :-) ...............

tonykaz's picture

I was one of Jim Theil & Kathy Gornick's Dealers, I spent time working with Jim, Kathy, Tom Theil at the Nandino Theil Factory.

Amps were the reason for most of my needing input from the Theils who directed me to Threshold Amps and Electrocompaniet Amplification Systems.

I never found a "cheap" Amp that could properly drive any of the Theil Line of Loudspeakers.

Jim never suggested ( to me ) that Watts were "Cheap" !

So, I'll suggest that Jim is being misquoted. I don't think Jim was ever being sarcastic because he wasn't an angry person.

High Quality Amplification has always been expensive in Dollar Cost and expensive to research, locate and own.

Which is one of the great things about Stereophile now-a-days, Stereophile has an abundance of Amplifier evaluators that go to extravagant lengths ( reminiscent of what Jim Theil and I did back in the 1980's ).

Tony in Michigan

Axiom05's picture

It drives me nuts that people can't make the effort to spell someone's name correctly. Jim Thiel.

Bob in Sarasota

rschryer's picture

I'm sure Toony didn't mean anything by it.

Best,

Roberb Schcryer

tonykaz's picture

Hello,

Yes, you are correct.

I've been dysfunctional about getting Jim & Tom's last name spelled correctly, for decades now.

I still have to check my spellings.

However, both Jim & Tom enjoyed a good relationship with me and we found homes for a significant amount of their factory's output.

My misspellings are innocent, I still get their and thier goofed up.

I'll try harder, I'm not trying to upset anyone's sensabilities.

I loved THIEL stuff.

Tony in Michigan

ps. I don't own Thiels now but my old Business Partner : Dr.George Buckley still owns an early serial number pair of CS3's

jeffhenning's picture

Two thoughts about this review:

• I guess you have to crack on Hypex when your amps have more distortion and noise - hey, Pascals are still good amp modules and they've proven themselves as being rugged in the pro market. They are, though, not quite as good as nCore tech.

• If you are building a $2.5K amp with the biggest metric being driving Duntech Sovereigns (truly great 25 years ago) or the like at full blast, you've missed the point. No rational audiophile clings to that paradigm. The "World-Killer", all passive speaker concept is dead. Much like vinyl, it's kept alive by people who value status and bragging rights over true fidelity to the original signal.

It's an amp with "respectable performance." Great. Makes me wonder, though, why Ken was so enthusiastic about it. Most likely the noise floor. That is a big thing, but, given the excess of distortion in the treble, I'd never consider this. So, the amp is OK, but nothing more.

On a different, but, tangential note, when was the last time any product really got called to the mat here or in any audio publication? It happens, but quite rarely here. Elsewhere, almost never.

Personally, I'm tired of reviews that have no measurements and end with a "sounds great to me". Most especially when every product reviewed is more incredible as the price rockets skyward ("This $5k Ethernet cable offers stunning midrange!").

High fidelity is a science. The art aspect comes into play when building the product. Unfortunately, most audiophiles do not embrace science. They embrace hype.

ken mac's picture

"Much like vinyl, it's kept alive by people who value status and bragging rights over true fidelity to the original signal." Is everybody happy?

Bogolu Haranath's picture

"Eschew obfuscation" ........... Anonymous :-) .........

ken mac's picture

Oh, I see you read a different review from a different publication. Nevermind.

georgehifi's picture

Here we have a stereo Class-D amp with 250watt into 8ohms and 300 into 4ohms.
Yet into the 93db 10ohm DeVore Fidelity Orangutan O/93 speakers.
"Using two Amps in bridged-mono mode greatly increased the flesh and blood of the sound of a single Amp, with no loss of dynamics."
How is this possible one amp should have p****d it in.
All I can think of with bridged amps the damping factor is worse, distortion is higher, low impedance drive stability is far less, maybe this can "flesh and blood out for the better"??????? certainly couldn't have been the extra watts one amp was more than enough.

And this ones really interesting for me "We've changed switching speeds" has anyone more info on this statement from Mytek?
As I'm a firm believer that switching speed is the Achilles heel of Class-D at the moment at around 600-800khz, and it should be 2-3 mhz so the output filter/s can do their job properly, only then will Class-D be fully appreciated.

Cheers George

Bogolu Haranath's picture

Wikipedia has lot of info about class-D amps, if you are interested ...........

dce22's picture

Your mixing things up,
"Achilles heel of Class-D at the moment at around 600-800khz, and it should be 2-3 mhz so the output filter/s can do their job properly"

That is for Digital direct Power DACS like this:
https://www.hypex.nl/img/upload/doc/an_wp/WP_AES112BP_A_true_one-bit_pow...

For self oscillating analog PWM best frequency is 400kHz:
https://www.hypex.nl/img/upload/doc/an_wp/WP_Globally_modulated_self-osc...

If you design Class D amp to self oscillate at higher frequency you will have real world physics problems and it will sound bad, it has been tried because most of the distortion in class d comes from the switching moment at high current so if you switch twice the rate you will double the distortion and so forth and all you will get is more flexibility on the negative feedback that you dont need in the first place you have plenty of feedback as it is.

Cheers

ken mac's picture

on what I hear, and the two amps in bridged mode outperformed the single amp. Not all things correlate to measurements, to stats, to yesterday's news. What I hear outweighs all other criteria.

Ortofan's picture

... a review and test of the Rotel RB-1582 MkII.
For $1600 you get 230W/ch into 8 Ω and 400W/ch into 4 Ω.
Plus no speaker impedance dependent frequency response aberrations.
https://audio.com.pl/testy/stereo/wzmacniacze-stereo/2899-rotel-rc-1572-...

Bogolu Haranath's picture

Check out "An amplifier listening test" on Stereophile references ..........

georgehifi's picture

Better look at the very limited supply (to Kings and Presidents) $30K aud Technics SE-R1 with special newly developed limited supply high speed "GAN-Fet" transistors (from the same guys who invented the Power Mosfet)
It uses a 1.5mHz switching speed, over twice as much as what around now.

Reactions from just a couple of press/reviewers to it's sound:
"Listening to tracks that we’ve heard 100s of times — and on excellent systems at that — is now a revelation of once hidden nuance and detail. Not only are we hearing things we’d never heard before, we’re hearing it in a way we’ve never heard it before. A music system that sounds like a live performance is a tough goal to attain, but Technics’ flagship nails it."

"This amplifier delivered some of the best reproduced sound at CES 2017. I persuaded Bill Voss to rip the contents of my copy of Rutter's Requiem to his media server's solid-state drive. The broad and deep soundstage, imaging, upper midrange detail, and bass extension were thrilling during the system's rendition of "Lord, make me an instrument of thy peace" and "Pie Jesu." I appreciated the work done by the Technics staff to prepare their exhibit suite with recessed sound-absorbing panels. I left wanting to hear more."

Cheers George

dce22's picture

Technics SE-R1 are so primitive design they dont even put output filter into the feedback loop, it has rising distortion in the high frequency range and alot of phase shift.

It does not matter if you use MOS or GAN FET the actual inductance of the circut board will not allow to delever the current for the rising edge on the pulse so it will distort like a mofo.

The best design of the type of amp that Technics is trying to do is Bruno Putzeys "A True One-Bit Power D/A Converter" by spliting 2.8Mhz frequency into multi phases then sum the phases into the inductor the whole system runs at 2.8Mhz but the FET's switch at low frequency, its zero feedback, volume is controlled by moving the power supply voltage so there is no digital bits losses, and without feedback to control the output filter you get phase shift at the high frequency range just like the technics design.

Self oscillating design like ucd ncore and such, that uses the negative feedback with the output filter to create the switching oscillator and correct for the filter problems and improve the distotion spectrum and reduce the EMI and RF, and reduces parts to around 10 to 15 transistors and improves the signal to noise ration and it self regulates the power supply.

400kHz bandwith is enough for audio amp if you got multi pole negative feedback.

difference between 400kHz with two pole output filter and 2 MHz with 2 pole filter (you need two pole filter to remove switching residual) is

400kHz rate gives 2 - 50 000 hz at 0,-3 db
2MHz rate fives 2 - 100 000hz at 0,-3 db

400kHz rate gives 2 - 20 000 hz at 0,-0.25 db
2MHz rate fives 2 - 20 000 hz at 0,-0.15 db

you cant hear 0.1db difference at 20kHz
but you can damn well hear 0.000X% THD vs 0.X THD

So stop with the you need 5MHz switching rate fallacy 400 khz is the highest you need for audio so its the best rate, if you go faster the PCB inductance will chokeout the high current pulse ramp (20 amps at 9 MHz harmonic for 400khz switching) you will get hundreds of mega herz of ringing on the squarewave that will pass thru the output filter like its not there, pulse will tilt so you will get high distortion, even 400 khz is too much for that currents but you need 400 for good sound.

Hope my explanation helps Cheers...

georgehifi's picture

That's why your left with this saw noise on the 10khz square wave.

https://www.stereo.net.au/forums/uploads/monthly_2016_12/583f6e91157f6_C...

Filtered out in the last year or so with Stereophile's ("Audio Precision’s AUX-0025 passive low-pass filter") hidden so you can't see it.

If it were a much higher switching frequency even more than the SE-R1 and filtered out totally this buzz saw noise at 10khz would not be there all, even without using Stereophile's AP filter.

Cheers George

dce22's picture

"If it were a much higher switching frequency even more than the SE-R1 and filtered out totally this buzz saw noise at 10khz would not be there all, even without using Stereophile's AP filter."

Not true! output filter is a 12 db down per octave it cant surpess the switching residual and when you go into the MHz range inductors go capcitive and capacitors go inductive filter will become high pass instead of low pass.

That is why when you switch at high frequency the PCB parasitics at high currents will choke the ramp rise of the FETs
(causing the squarewaves to miss the high harmonics creating ripple at the top or down off the square)
and it will generate 100MHz ringing on the squarewave that will go thru the filter and jam FM and VHF RF singals.

About the so called "buzz saw noise" if you use a high quality scope you will see that is not a saw but filtered squarewave that looks like a sinewave but with parabolic functions instead of sine functions.

Now this parabolic like sine wave is crucial to any self ocillating switching amplifier and it has to be prestine for the amp to work with low distortion like nCore amps,

because this type of amps does not have triangle wave generator to modulate the audio (the cleaner and stable the triangle the lower the distortion in old fashion class d very difficult thing to do and requiring hundrets of transistors)

So the big invention of the ucd, ncore amps is that the "output parabolic like sine" is fed into the input with the audio output of the amp as any negative feedback using the output filters phase shift in conjunction with negative feedback control circut that corrects for the filter audio distortions and as it goes to above 200khz it releases the phase shift correction and creates a oscillator at 500kHz that is free to move around from 470kHz to 530kHz as it is needed according to the music,
because it is connected to the input signal it has non of the jittery distorting problems that old school Triangle wave modulated Class D amp have.

So if you switch at megaherz frequency you will not remove it you will just lower it at kiloherz range and you will let megaherz signals blast thru that will RF radiate from the speakers cables.

Lets say you use balance current type of circut like Crown K1 or Mark Levinson 53 that switch into phases at 500kHz slow speeds than combine them into 4MHz switch rate.

https://www.stereophile.com/content/mark-levinson-no53-reference-monoblo...

And you supress switching residual into the noise floor you are stuck with a triangle PWM amp that have alot of problems.

ML no.53 is a triangle based amp that uses 1000 transistors, equivalent self oscillating class d like nCore uses 15 transistors.

You can compare Mark Levinson 4MHz monster of components to nCore 15 transistors and one filter a on a board.

nCore1200 with Audio Precision AUX-0025

https://www.soundstage.com/index.php?option=com_content&view=article&id=...

nCore400 WITHOUT Audio Precision AUX-0025
https://www.diyclassd.com/documenten/download/860
drill down on the pdf to see 4ohm and 2ohm measurments.

nCore amp is better in any way especially the nc400 with two transistor matched output stage and discrete input opamp.

Lorenzo-Italia's picture

it would be nice if Michal Jurewicz could better articulate below statement:

"Duntechs, with their multiple drivers and complicated crossovers, are a very difficult load," Mytek's chief designer, Michal Jurewicz, told me. "Hypex [class-D modules] cannot drive it, the amps collapse, but this Brooklyn Amp does it with ease.
Read more at https://www.stereophile.com/content/mytek-brooklyn-amp-power-amplifier#g...

considering that Mytek amplifier according to JA could not yet be measured at 2ohms

- https://www.stereophile.com/content/mytek-brooklyn-amp-power-amplifier-m...

while Hypex Ncore implementation actually did it succesfully

NAD M22
https://www.stereophile.com/content/nad-masters-series-m22-power-amplifi...

Bel Canto
https://www.stereophile.com/content/bel-canto-eone-ref600m-power-amplifi...

theta digital..
https://www.stereophile.com/content/theta-digital-prometheus-monoblock-p...

in addition Duntech, is a first order crossover speaker 3-4ohm with rather flat impedence and phase curve vs frequency.

http://www.duntech.com.au/english/products/classic-series/sovereign.html

(couldn't find stereophile review, pls consider John Dunlavi SC VI as reference design for Duntech)

https://www.stereophile.com/content/dunlavy-audio-labs-signature-sc-vi-l...

waiting for mr. Jurewicz explanation...

My Best Regards

Lorenzo from Italy

Post Scriptum
Mr. B. Putzeys, could you pls let us know about Hypex (NCore) ability on difficult speaker loads?

georgehifi's picture

Yes true because if your filtering the same 12db per octave but at 3mHz (instead of 600kHz), by the time you get to 20khz it's all but gone, not like we have now!

Cheers George

dce22's picture

Self oscillating amp is a must to remove triangle wave problems and you cant do that without letting switching residual thru the filter (UCD nCore ICEPower amps are big phase shift oscillators) to feed it back into the input so it will oscillate,

and you dont need Mhz switching because class d is a analog amp that contracts and expands the squarewave according to the music signal no resolution loss.

https://www.youtube.com/watch?v=3Tr1GbrS_Z8

This is not a good class d amp so you can see the ringing at the start of the squarewave, this ringing can be removed with carefull design at 500kHz frequency but at 4MHz it will become massive ripple that will span from 100MHz - 400 MHz creating a tv transmitter and output filter will not filter these frequency inductor will go capacitive and it will connect directly to the speakers cable that will transmit into the airwaves RF.

The switching residual does nothing to the speaker, the twitter can not feel anything at 500kHz 400milivolts, the residual is like a ultrasonic flute that is playing a note very quietly in the background without interfering with the music at all it does not intermodulate with the audio or distort it in any way and id does not radiate RF because the cables are too short for the wavelength.

You can make a decent 4Mhz amp like Mark Levinson did but it will cost a fortune (4 inductor 16 output transistors per channel 1000 transistors in the PWM) and it still perform worse in listening test and on the bench in noise and distortion DC-50Khz compared to nCore 15 transisors and one inductor

Cheers....

jgossman's picture

Especially as electricity gets more expensive and environmentalist creep into every aspect of our lives (not always a bad thing, sez this Republican)

All I hear in this review and discussion is blah blah blah, still not as good as a good mosfet amp.. Blah blah blah, buy a Pass design from Pass, Threshold, Nakamichi, etc. Blah blah bla, the homely DH-200/220 is still one of the best measuring (and pretty good sounding amps) ever and can be had for a song. Etc, etc. Good old power hungry Tetrode and Mosfet amps still just seem to be better. And we know how, at nearly every price point, to make them sound wonderful with many if not most speakers.

Also, all the talk of switching frequency all I hear is "what's the frequency, Kenneth?" - tape hiss included.

dumbo's picture

I'm continually baffled by audio equipment these days. Manufacturer says their AMP can drive difficult loads with ease but when simply placed on a test bench and these claims verified, the bottom drops out of their claim and they look foolish.

Do these people not have test equipment of their own that they use when designing a product? I wouldn't dream of attempting to design and build audio equipment for a living without test equipment.

Submitting a product for review to a magazine like Stereophile knowing that the product specs/claims will be verified on the test bench should be at the top of the manufacturers list of things to get right before submission.

I'll give Mytek some slack though since its product here is not priced in the stratosphere unlike some other products we've seen that cost 5 figures and leave the factory with critical flaws. Amazing Stuff!

Stereophile, please don't change a thing when it comes to your unique review approach by actually measuring this equipment that you receive. Its one of the main reasons why I am a loyal subscriber. Manufacturer claims need to be put in check so the consumer can make informed purchase decisions. Too bad none of the other rags have the same philosophy as Stereophile when it comes to reviews.

Buying a product based on a wink and a smile and only using your ears afterwards doesn't fly these days with the Internet at everyone's finger tips.

X