It sounds like you have a lot of experience which I think is critical in building a system you really enjoy. Listening to the opinions of experienced individuals on audio forums like this is helpful but I believe most of us learn best from actual personal experience. The process of just trying different things ( amps, sources, speakers, positioning, room treatments, cabling and even tweaks), over time, results in a solid foundation that not only lets you know what sounds good to you but also how to attain those sound qualities in your own system. My interest in class D amps began by reading numerous positive comments on them here and on other audio forums. Eventually, I just bought one (a ClassD Audio SDS-440-CS stereo unit) more out of curiosity than anything else. I was amazed at how well this small, light, efficient and inexpensive ($600) amp powered my inefficient Magnepan 2.7QR speakers. It was better in every respect than the class AB Aragon 4004 MKII amp I used previously and it was about a third of the size, weight and cost. Actually trying it out in my own combo music and ht system convinced me how exceptionally well this class D amp performed and I was now curious about the differences between class D amps. Within a year, I bought a few more class D amps: a stereo Emerald Physics EP100.2SE and a pair of mono block D-Sonic M3-600-M amps. These both sounded very good and similar but with better dynamics and improved midrange/treble qualities I’d describe as warmer and smoother. My entire 5.1 ht surround and 2-ch music system is now powered by class D amps and I’ve sold all 3 of my previous stereo class AB amps. My system’s never sounded better and there’re no downsides. I think the class D experience I’ve gained has also allowed me to confidently realize that class D critics are typically either misinformed, have an ulterior motive or simply have no personal experience using good examples of them.
As always ’compared to what", Well, I was in the biz in the late 1990s-- early 2000s. Dedicated 20 amp line, and was testing various PLCs.. Back then the PS Audio P300 on the front end was awesome.
At one point I had Rogue M150 monos with full sets of cryoed 6550s and EL 34s (+ cryoed NOS driver tubes), a Lector pre (custom ordered with XLR output) and several tube CD players. everything was on Stillpoints with Risers and custom Harmonic boards (made from violin wood): I was/am an isolation nut. IMHO, nothing is as good as inexpensive Machina Dynamica Springs, which isolate in all 3 dimensions). Various speakers, but at one point I had Harry Pearsons Genesis Vs, and later a prototype pair of 7ft Nearfield Pipedreams with a 10K MSRP (we were dealers), followed by Usher 6371s> KCIIs. You get the picture
I started getting into class D with PS Audios various iterations; I still have a GCC 250 (modified as new by Underwood HiFi driving my video system. In the main rig I had W4S stereo amp> W4s MC 250/500> Emerald Physics 100.2SE with custom fuses) and currently Audio Alchemy DPA- 1 (stereo amp) and matching AA DDP-1 (dac/pre). CD is a Marantz HD CD 1 used as a transport via HQ coax, and an Oppo 105 with Linear Power Supply and incoming IEC wire upgrade for high rez discs, which I haven’t yet listened to in months. Speakers are Emerald Physics KCIIs (Clarity cap and WireWorld internal XO wire upgrades) which replaced Magnepan 3.5Rs and 2 SVS (Ultra subs, both turned off after the cable changes
So, when I say I haven’t had this level sound quality in decades, that says a lot, to me at least. .
Only budget limits me at this time from Nuprime Evos, GaN...
"Paraphrasing your reply, Class D is ruthless on ancillary kit and cables. They should be upgraded before bashing class D."
Hello tweak1,
Great to hear that you’re benefiting from the detail and clarity of class D technology to significantly upgrade your system’s ancillary power cords and cables. I had similar improvements in my system by installing custom made XLR cables between preamp and class D mono blocks and power cords on my monos (all ordered from James Romeyn Music LLC). I also installed dedicated AC lines for the monos that made obvious improvements. Similar ancillary kit and cable changes, as well as the quality level of source recordings, were never this clearly noticed through the decent quality class AB amps I previously used.
"^ The reason we aren't using GaNs yet is we are in a prototype stage. We developed a means of eliminating the need for dead time circuitry in class D amps (for which we have a patent pending).
The main reason to use GaNs is to minimize dead time (dead time increases distortion). So you are seeing GaN-based class D amps right now that have no dead time circuits simply because the transistor is so fast that with conventional switching speeds no dead time circuits are needed. We're able to switch at the same speeds with conventional devices."
Hello Ralph,
I would like to retract my complete previous post addressed to you. I had a hunch you had your reasons for not using the new GaN FETs, but I had no idea those reasons were so completely awesome and with a patent pending, to boot. This is really big news that sounds like a major breakthrough in your class D amp efforts to me.
Breaking News: Atmasphere Ralph just killed dead time. Congratulations! Please accept my apologies for ever having doubted your judgement. The legend of your amp engineering and design prowess just continues to grow. Best wishes on your patent application. Yahtzee!
UPDATE: I replaced the old (~ 10 years) mid line PS Audio XLR with WireWorld newest Series 8 Silver XLR ($425) WOW. after a couple hours I was hearing a grungy distortion, so I decided to replace the PC I was using with my WW Eclipse Series 7 PC (the one that I replaced prior to inserting the PS XLR) OMG. This is the most natural my system has sounded in many years. Oh, and subs are turned off but the Emerald Physics KCIIs have really good bass to ~ 40, which is ample for most music. Where I was using the F4 digital filter on my Audio Alchemy Dac/Pre I am now on F1, which is the least filtered
Paraphrasing your reply, Class D is ruthless on ancillary kit and cables. They should be upgraded before bashing class D
^^ The reason we aren't using GaNs yet is we are in a prototype stage. We developed a means of eliminating the need for dead time circuitry in class D amps (for which we have a patent pending).
The main reason to use GaNs is to minimize dead time (dead time increases distortion). So you are seeing GaN-based class D amps right now that have no dead time circuits simply because the transistor is so fast that with conventional switching speeds no dead time circuits are needed.
We're able to switch at the same speeds with conventional devices.
What this means is that for any given semiconductor tech that comes along (GaN and whatever **will** follow) we'll always be able to switch at higher or equivalent speeds with older technology (which is less expensive, although GaNs are already pretty inexpensive, being only about $3.00 each). Of course the flip side is that we can use the latest tech and switch faster. But in a prototype that sort of thing isn't necessary.
Thanks for the update. Very interesting and surprising, too. I’m not surprised you’re building your class D modules by hand but I thought you’d decide to utilize the faster switching GaN FETs in your amp. I would think not using them would handicap your amp’s performance in relation to the competition. I assumed you’d choose the best parts for each amp function in order to optimize overall performance. I’m just an enthusiast of good music played through high quality audio equipment but even I can hear the improvement in sound quality of the ADG Vivace mono blocks despite listening to them on a YouTube video on a laptop via headphones. I think the improvement would likely be even more obvious and impressive heard in person. I may be attributing too much credit to the faster GaN FETS, rather than the typical silicon MOSFETs , for the improvement in sound quality I hear in the new ADG amp. I know there're many other design factors involved in determining an amp’s ultimate sound quality. But I understand that you’re an amp designer who’s also responsible for running a successful company and there’re very important factors involved in your choices that I’m not aware of. You certainly don’t owe me an explanation, I think I’m just a bit perplexed and disappointed.
I'm also curious about how your development of a class D amp is
progressing and whether it will utilize GaN or any other newer
technology.
@noble100 Right now we're not using GaN transistors but they are certainly on the radar. So far we've been building our modules by hand. GaN devices are much smaller than what we are using, which makes the assembly a lot more difficult (or easier, if we farm it out). Otherwise progress seems to be pretty good.
I found some interesting You Tube videos of the new ADG Vivace GaN mono blocks:
1. A pair of the new ADG Vivace GaN monos driving the mids/treble of a biamped speaker with the bass driven by an older pair of Rowland Model 12 class D monos compared to 2 pairs of Rowland Model 12s driving both.
2. A pair of the new ADG Vivace GaN monos driving the mids/treble of a custom biamped Magnepan speaker without the bass being driven at all compared to 2 pairs of Rowland Model 12s driving both the mids/treble and bass.
It is true that the comparison is limited by the audio quality on a You Tube video, but I found the audio quality sufficient enough to still convey the clear superiority of the GaN amps. Of course, I’d prefer comparing the sound quality in person. I also thought the ADG Vivace amps, with the gimmicky large tube shell containing the GaN FETs protruding from the top of the amps, actually looks much less goofy in action than I originally thought it would. My current opinion is that it’s a good tip of the hat to the fondness most tube lovers, including myself, have for the warm glow of tubes in a darkened room that is remininscent of good music flavored with a touch of euphonic joy. These videos struck me as satisfying confirmations of the benefits GaN FET technology can contribute to the sound quality of virtually all solid state amps.
I don't know what the general opinion of those following this thread is but my opinion is that these mono blocks are excellent amps. Kharma, mainly a hi-end speaker and cable seller at the time, introduced their first class D amps (the MP150 and MP350) in 2007. Kharma owner, Bruce Oosterum, collaborated with class D UcD inventor, Bruno Putzeys, on these UcD based amps. Putzeys had claimed to be able to bend the sound of any class of amp, be it A, AB or D, to his will. So the design goals for the new Kharma amps was to make them sound like a tube amp in mid and high frequencies and retain class D's traditional excellent bass response. As you stated, according to the reviews of the MP150 from The Absolute Sound, Stereophile and 6 Moons at the time, they were very successful. Around 2010, I heard a pair of MP150 mono blocks driving a set of Magnepan 20.1s playing vinyl and it sounded spectacular. I wanted to buy a pair for my Magnepan 2.7qrs but the price was too steep for me at that time; about $7K/pr. if I remember correctly. I'm very satisfied with the much newer and higher powered D-Sonic class D mono blocks I'm now using with my Magnepans but I wouldn't be surprised if a pair of the Kharma MP150 monos, even a 10 yr old used pair, sounded just as good or possibly better. However, I heard them on the top Magnepan speakers which isn't really apples to apples, either. I'm also not sure whether Kharma has updated the MP150 over the years. I think Kharma has since offered an MP1000 model amp that is class A/AB.
What's the general opinion of the Kharma MP150? It got rave reviews when it came out, but at this point the amplifier is 10+ years old. I presume it's been given updates over the years. One reviewer claimed it bested the darTzeel stereo amplifier.
I agree the glass tube containing the GaN module is a bit goofy.
But I think something like this on a class D amp, a convenient location where some type of plug-in is inserted to change the amp's sound characteristics using a variety of purchased opamps or dsp chips, might be kinda cool. Like Nord but more convenient/accessable. Maybe they could offer 'Classic Tube Sound', 'Flea Watt SET Sound with SS Bass', 'Lamm Tube Amp', "McIntosh', 'Pass Labs SS Amp', etc. They could also have a class D preamp with these plug-ins so one could match various preamp qualities imparted to various amp sounds and tailor the sound just to their liking. I think this type of technology could be feasible in the near future.
The manufacturer trying to confuse people with the "tube" doesn't pass.
It's not really a tube, just the bottle of one with the GaN module stuffed into it. I think he regrets doing it as he did say,
"Company founder Alberto Guerra admitted that he did it largely for the sake of visual aesthetics. “Otherwise a class-D amp just looks like a box,” he said. The amp uses gallium nitride MOSFET output transistors, which Guerra says switch faster and allow the amp to have a noise floor in the -120 to -130dB range. Power is rated at 200W into 4 ohms."
I want to hear a GaN amp with the higher switching frequency and a higher low pass filter. The manufacturer trying to confuse people with the "tube" doesn't pass.
I have owned/heard Hypex NC400, TI 3116/3118, ST TDA7498.
I know NC400 is highly rated. However, I prefer my Tripath TA2022 and TK2050 Topping amps to it.
Tripath doesn’t measure like others but who cares. I like what I hear. That’s why I have ears for this hobby:) Fast, slow, distortion, this, that. I don’t care.
As long as my system gives me the feeling of being there, I am good. So far Pass Labs Aleph 3 did that the best. Second Tripath.
I think of ClassDAudio as the bargain center for class D amps. This is the place to go if you want high quality class D sound for the least amount of money. About 4-5 yrs ago, there was a lot of buzz about how good class D amps were getting and that they were moving beyond just good sub amps and were beginning to be considered very good sounding amps from top to bottom frequencies. They seemed to be the amplifier technology of the future since they not only sounded very good but were powerful, could easily drive low impedance speakers, were smaller, lighter, more electrically efficient and ran cooler than other more traditional ss and tube amp types. I was very curious to try one and see what all the fuss was about. So, I called ClassDAudio and talked to the owner, Tom Roth, who's very nice and knows a lot about class D. He recommended I try one of his completed amps. the SDS-440-CS, to drive my large 4 ohm Magnepan 2.7QRs. This was my first class D amp and it was an excellent performer. Mainly out of curiosity, I've moved on to a few other class D amps but the ClassDAudio is still operating flawlessly driving the rear surrounds in my system. I expect his new class D amp using the GaN FETs will also be a bargain. I find his comment that "were're still finishing case design" to be a little worrisome. While he makes great sounding class D amps using lesser known modules and traditional toroidal power supplies, the styling of his amp cases are typically, and to be very generous, ugly as sin. Think anti-Jeff Rowland Design Group style. Hopefully, this amp case's styling will match, what I expect to be, the great sound of his new amp.
Here is a an email back to me from the US company "ClassDAudio" regarding the use of the new GaN Fet technology in any of their completed amps or very well priced Class-D kits they make, that use linear power supplies!! https://classdaudio.com/amplifier-kits.html
"Hi George,
These will not be available in kits. These amps are complex and expensive to manufacture. We’re hoping to have complete amps ready maybe in about a month. We’re still finishing case design. Tom"
check-out these Class D offerings as well. And 'no,' I am not affiliated with this company. I just own a pair and have talked directly to the owner / designer...had them since July 2017 and love 'em. I listen circa 6hrs / wk. PM me if you have questions www.cherryamp.com
I think I understand; while GaNs do switch much faster than traditional MOSFETs they still require some driver circuit current to operate. The use of GaN FETs results in significantly lower gate capacitance and stored charge but not to zero. You're stating the most important benefit of using GaN FETs in a class D amp, however, is reducing dead time (possibly to zero at current class D switching frequencies.) since this allows for the further reduction of distortion. It seems to me that the benefits of GaN technology will improve the performance of all types of ss amps, not just class D. Please let me know if I'm misunderstanding anything. I'm also curious about how your development of a class D amp is progressing and whether it will utilize GaN or any other newer technology. I'm very interested and anxious to actually audition and experience the performance improvements gained through well designed amps incorporating the best of existing and recent technology. Thanks, Tim
The EPC eGaN FETs switch 10x faster than silicon MOSFETs and have zero
stored charge. I'm guessing that probably improves sound quality when
used in a class D amp.
While they are faster its incorrect to characterize them as having 'zero stored charge'. The gate (input) capacitance is the big issue; on traditional MOSFETs it can easily be around 2000pf, which requires a bit of current from the driver circuit to switch the device at speed. GaNs tend to have less gate capacitance (about an order of magnitude less, depending on the device) and that is part of why they can switch faster. But that gate capacitance still plays a role in the driver design. Much moreso than actual switching speed, getting dead time down is what reduces the distortion in a class D amp. Many of the GaN devices switch fast enough that amps with zero dead time can be built at pretty close to current switching speeds (400KHz or so).
"Which Class D Amplifier? PS Audio, Ghent, Nord, Merrill or other??? Which company is producing the best sounding Class D? Which models should I be looking to demo?"
singintheblues,
Since you never listed your budget and stated you’d like to demo the best current class D amp, I’m assuming that means price is of no concern to you. If this is the case, I would suggest you demo the new Merrill Element 118 mono blocks. They utilize the latest very fast switching GaN FETs, have a PWM switching carrier frequency in the MGHz range and I just read a great review on them on Enjoy the Music. Here’s a link: http://www.enjoythemusic.com/superioraudio/equipment/1018/Merrill_Audio_Element_118_Monoblock_Amplif...
Just get the GaN Development board or eGaNAMP 2.1 Evaluation Kit Stereo Evaluation board already made up, with everything inputs outputs, give it +/- 32v power and put it in a box. I believe Digikey has them, and many others.
Thanks for the link to the EAS™ eGaNAMP2016 amp module. I’m a bit confused, is this an EPC or EAS class D amp module? Or is EAS just using a standard EPC module for their amp?
I was assuming that EAS built a proprietary module using EPC eGaN FETs using either an EPC or Peregrine driver but I'm not certain. I was also assuming EAS intended to sell their modules to OEM amp manufacturers and not to individuals for diy amps since no prices are listed. .. I noticed the EAS™ eGaNAMP2016 amp module is amazingly small (4 x 2 inches) and efficient (96%). The switching frequency is still sub 500KHz but, as you stated, this can be raised substantially with the use of heat sinks. Class D sound matching or surpassing the sound of class A?
Please buy 4 of these modules from EAS and put them in nice chassis with XLR inputs, heat sinks and at least 1.6 MHz switching frequencies. I’ll buy a pair and you keep the other 2 and we’ll report back here on the performance results.
Here is the PDF to the
eGaNAMP2016 GaN amp. Steve Colino said if one wants even better sound from it, you can add a heatsink to those GaN fets and take the switching frequency up to 1.536mhz.
The EPC eGaN FETs switch 10x faster than silicon MOSFETs and have zero stored charge. I'm guessing that probably improves sound quality when used in a class D amp. . Elegant Audio Solutions in Austin, Texas, created a class D amplifier (200 w at 8 ohms and 400 w at 4 ohms) using the EPC eGaN FETs with THD+N as low as 0.0005% and very low feedback. Moreover, this is done without the need for a heat sink and eGaN-based amplifier can plug directly into the standard amplifier implementation of many existing systems. I'm very interested in auditioning this amp in my system. Here's a link to the amp photo:
Anyone want to volunteer to make me a pair of mono blocks using a couple of these amps placed in nice aluminum chassis with XLR inputs, IEC jack and rocker ON/OFF switch on the back and a single blue power status LED on the front?
GaN-FET manufacturers will be important to the implementation of the GaN tech in Class D audio amplifiers. And yes, wide spread availability of the GaN-FET’s will be needed to drive costs down. But GaN-FET modules designed for Microwave and RF applications will not benefit HEA class D applications. Just saying...
Looks like GaN is starting to take off. Not only Texas Instruments (Burr Brown) who are into the manufacturer of GaN transistor technology, but it seems Analog devices now also.
GaN is already being developed into Class-D audio by a few amp manufacturers now, with great feedback on it's sound, compared to the older technology.
It seems you've discovered another benefit of class D amps that I don't think has been mentioned thus far in this thread: good examples of class D amps are basically a 'straight wire with gain ', which is numerous experts' definition of an ideal amp. Distortion and the noise floor are measurably so extremely low that it results in nothing being added or subtracted from the inputted signal. This causes the overall presentation to be very detailed and neutral. The benefit of these qualities is that it allows users to much more easily discern the affects of different power cords, interconnects and spkr wires on your system's overall sound. With my prior good quality class AB amps (Adcom, McCormack and Aragon) I thought I could discern subtle differences but, in retrospect, there may have been some placebo effect occurring. With the good quality class D amps, the subtle differences were discerned much more easily. On a larger scale, the clarity and honesty of good class D amps will also allow you to much more easily discern weak links in your system such as upstream components and source recordings. I had always thought I preferred a warm overall system sound. For about 5 years previously, I used a tube preamp (VTL 2.5 with NOS Mullard tubes swapped in) paired with solid-state amps to achieve this warmth. After comparing the overall sound with and without the tubes, however, I found most of my favorite recorded source music sounded just as sweet to me without the tubes. So I sold my VTL and a set of 4 just purchased NOS Mullards to a good friend and have not regretted it since. This same clarity and honesty also applies to recorded music sources. There's no masking or coloring of the signal so recordings that sounded good to on previous amps may not sound as good using good class D amps. The recordings are just faithfully reproduced with warts and all. Bad recordings will sound like it and good recordings will sound especially good, the differences being obvious, .I discovered my CD collection consisted of mainly good recordings with just a few clunkers (for some reason my Cold Play CDs sounded much worse but still good in my car system). Just after swapping out my class AB amps for class D, I also added a computer audio setup; consisting of my laptop running JRiver Media Center, a Synology NAS and using my Oppo 105 as a DAC/Player. I ripped my entire CD collection to the NAS and began downloading some high resolution 24 Bit/96KHz music files ,too. All the CDs sound very good but the music recorded direct to hi-res 24/96 sounds incredibly good; by a wide margin the best I've ever heard on my system with solid/stable 3D sound stage and the large dynamics I only previously experienced with live music. My main cautionary message is that class D amps may not suit everyone's tastes or system. For example, those that don't have the funds to upgrade upstream components that may suddenly sound deficient. Or those who prefer a more colored system sound and don't want a very detailed presentation that will reveal the true quality of all of your recordings. However, users of good class D amps are still able to tailor the sound of their system sound via the choice of preamp used. The amp will just faithfully amplify the outputted preamp signal so it's critical that the preamp outputs the desired sound qualities.
Nord was offering an upgrade billet chassis (I think for the NCore only), but it’s no longer posted as an option
I read another review citing power cord sensitivity. I changed one out and did get a substantial overall more organic presentation.
Based on that, last night I swapped out a Surfer Cable XLR (silver; a very good value @ $150), but when I replaced it with a PS Audio copper XLR (not sure which model, but I own it) it took about an hour to saturate, before the music refocused. Tonal tilt now favors of the midrange/base, and a lot more fuzz on the peach. It’s the kind of improvement I would expect if I can ever find a Audio Alchemy PS 5, outboard power supply for my AA Dac/Pre
Tossing arguably superior circuits or eval boards into a box will not likely make for a superior product providing a lasting satisfaction. Designers care about circuit board layout, trying to minimize circuit trace paths from RFI and noise perspectives. And then there are the vibration control and global noise/RFI isolation and reduction issues that come into play.
Very nice post with some very interesting information and thoughts from a system tuner's perspective. As a layman, I think it's an important reminder that designing and engineering a good sounding audio amp, regardless of type, requires making many good smaller decisions (based on one's knowledge, experience and goals) all contributing to the final amp creation's sound. Designing very good class D amps seems to be especially difficult since amp designers must make decisions based not only on their acquired experience and knowledge of traditional amp design but also must gain experience and knowledge of how to incorporate the newer and higher performing component parts into their designs. Thank you, Tim
Actually not to take sides with anyone, but I have heard the sound that George mentions. However I hear this problem with all classes of amps, who use certain chassis. Chassis can and often do play a role in mid and upper end distortion. So do transformers being to close to caps.
If you take your amp (any amp) apart and spread out the components you will be able to find the distortion cause by component cramping.
Class D amps in their little squeezed boxes have problems, but also problems come with these smaller boards used.
I like Class D a lot, and there are lots of advantages over A and AB as far as mass goes obviously but there are more steps to take in the mechanics of most of these amps that have a ways to go. I'm working on a few of these issues as we speak and can say with almost certainty the amp I will use for our Rev Combo will be Class D, the low end amp already is Class D.
Again a very important thread, minus any absolute opinions. There's good in all but sometimes we over look the simple things when designing.
Mapman: " Also I do not hear the issues George claims even at this modest cost."
Reports from those who do hear issues, with class D or T, are scarce. Rumor has it that georgehifi’s real father is an Australian sheep dog, perhaps he can hear dog whistles, too. I’m still waiting to learn from georgehifi exactly what these supposed class D sonic shortcomings actually sound like. His very rare previous descriptions were so vague that they’re meaningless. Has anyone else claimed to hear these issues besides him? I don’t recall anyone else chiming in to claim they hear issues with class D. I faintly recall a single poster, who didn’t have a user name of georgehifi, claiming they listened to some D amps stating that ’something was missing’ or ’it lacked soul’ but nothing specific that could be relied upon with any confidence nor even be considered a corroborating anecdotal description since I believe this was claimed only by a single poster.
As Steve Colino of GaN (EPC) has said below, there is no need for any heatsink on the GaN transistors if they are used at todays switching speed. Only if you use the option to raise that switching speed to gain the extra sound quality, then there is the need for a heat sink to be mounted to the GaN transistors, as in the Merrill and Technics case. Once again you twist things, "it’s not a good look" if you try to put s**t on this new technology while your trying to release your own Class-D amps.
Excerpts from Steve Colino’s email to me.
V.P., Strategic Technical Sales
EPC (Efficient Power Conversion Corporation)
"EPC9106 GaN FET we were able to get outstanding sound quality in the amplifier without heatsinking. Our GaN FETs will give an even higher performance difference compared to MOSFETs in both sound quality and efficiency at 1.536 MHz switching speed. The eGaNAMO2016 is a GaN FET amplifier platform that is capable of delivering a very high performance 200 W into an 8 Ω speaker load (400 W into 4 Ω) [8]. Its 96% system efficiency without requiring a heatsink. You can take the value in sound quality and eliminating heatsink assembly costs while delivering your customers increased efficiency is a smaller form factor."
" THERMAL CONSIDERATIONS With this high efficiency, the EPC9106 design allows for the complete removal of any classical or historical heat sink requirement. This elimination of the heat sink also reduces the potential contribution to radiated EMI/EMC emissions.
And from Merrill Audio who use the higher switching speed
" Internally
the Element 118 Power Amplifier Monoblock PCB boards are manufactured
to the highest excellence available and further engineered for
sustaining a most stable temperature distribution. Using 8 pounds of
pure copper per monoblock, the highly refined heat distribution system
maintains a steady temperature environment on the PCB boards, a
condition absolutely essential for linear operation."
George, looks like you made my point.
I tend to believe the manufacture of the board, EPC and it’s designer
Steve Colino, who stated only heatsinking is required on these GaN
devices if the switching frequency is raised. Not by what you say.
Well you're not likely to be designing a class D amp anytime soon, so its no worries for you. For those that **do** design such amps, the idea of no heatsinks is scary to say the least, and the prudent designer that knows the amp is going to see some thermal abuse in the home will add heatsinks. To not do so is to court disaster- If it turns out that a model is overheating, the boards in the unit will have to be redesigned and that sort of thing can put a company under really fast.
Heatsinks are required, even for Gan devices switching at lower speeds If you ran this thing under heavy conditions, it would fail
And yes Gan devices have their own heat pad underneath which is sweated to the ground plane of the PCB. But that will be in every case that they are used in, your not going to twist it any other way.!!!! https://ibb.co/jTWd9nx
I tend to believe the manufacture of the board, EPC and it’s designer Steve Colino, who stated only heatsinking is required on these GaN devices if the switching frequency is raised. Not by what you say.
And from Merrill Audio who use the higher switching speed
" Internally the Element 118 Power Amplifier Monoblock PCB boards are manufactured to the highest excellence available and further engineered for sustaining a most stable temperature distribution. Using 8 pounds of pure copper per monoblock, the highly refined heat distribution system maintains a steady temperature environment on the PCB boards, a condition absolutely essential for linear operation."
You can buy your own EPC GaN boards from Digikey, and yes they operate with no heatsink. Because
EPC’s Steve Colino said to me, (and I posted up his email), they are at
600khz switching speed, you can increase that to 1 or 1.5mhz as Steve
said, but you will have to use a heatsink on them.
@georgehifi Yes, the board itself is the heatsink, but is an evaluation board. If you ran this thing under heavy conditions, it would fail unless cooled by a fan or the output devices were mounted on a proper heatsink.
If when the TI GaN technology reaches this product, assuming it has not already (don’t know), I hope the price does not jump too much.
It sounds very good! Much better than I could have hoped for the cost, though I am only using it with a pair of old Boston A40s in a lesser used 2-channel AV system currently. Also I do not hear the issues George claims even at this modest cost. Enjoying it thoroughly, though much different sounding than the classic old NAD 7020 it replaced. More like my other two much pricier Class D amps.
It got a near perfect 5 star average rating with 100s of reviewers on Amazon offering up similar praise. I guess they did not hear any problematic artifacts either.
Here we go hopefully, one of the majors have got the rights to make it, watch Class-D take off now, and finally compete with the best of Linear amps in the mids and highs and beat it in the bass as it always did.
Heatsinks are required, even for Gan devices switching at lower speeds, regardless of what EPC allegedly said.
This is not correct.
You can buy your own EPC GaN boards from Digikey, and yes they operate with no heatsink. Because EPC’s Steve Colino said to me, (and I posted up his email), they are at 600khz switching speed, you can increase that to 1 or 1.5mhz as Steve said, but you will have to use a heatsink on them.
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