GAN FETs The next big thing in amps ?

[Bubo]

Starting to see GAN FETs in new Amp designs

Specs out much better than the Class D offerings we have seen

Was Mil Tech until recently

 

Gallium nitride (GaN) ICs

Maximize power density and efficiency with our portfolio of GaN power devices for every power level

Our family of gallium nitride (GaN) FETs with integrated gate drivers and GaN power devices offers the most efficient GaN solution with lifetime reliability and cost advantages. GaN transistors switch much faster than silicon MOSFETs, offering the potential to achieve lower-switching losses. Our GaN ICs can be used in a wide range of applications, from telecommunications, servers, motor drives and laptop adapters to on-board chargers for electric vehicles.

https://www.ti.com/power-management/gallium-nitride/overview.html

 

What is gallium nitride (GaN)?

Gallium nitride (GaN) is a wide bandgap semiconductor that enables higher power density and more efficiency than traditional silicon metal-oxide semiconductor field-effect transistors (MOSFETs) and insulated gate bipolar transistors (IGBTs). GaN processes power more efficiently than silicon-only solutions, reducing power loss by 80% in power converters and minimizing the need for added cooling components. By packing more power into smaller spaces, GaN lets you design smaller, lighter systems.

 

Some Eng articles on Gan, some audio related

https://www.electronicdesign.com/leaders/power/power-supplies/article/21174367/gan-fet-technology-solving-audible-challenges-for-highperformance-audio-amplifiers

[Schu]

what amplifiers are you seeing this in?

[rplace]

Orchard Audio GaN amp(s) will probably be my next purchase if/when I feel the need to try something different than my First Watt top end hypex low end current set up

[Bubo]

18 hours ago, Schu said:

what amplifiers are you seeing this in?

One of the Japanese majors has gone GAN

This one is Korean

https://www.crutchfield.com/S-3h5jpiPRM59/p_358RA180/HiFi-Rose-RA180.html?

 

There was at least one at AXPONA

 

I suspect they will replace the current class D in the surrounds amps in the next 12-24 months as the GAN Audio chip sets ramp up.

More efficient, less heat, greater density, smaller power supplies = cost reduction per watt

with better spec out

 

SEARCH "GAN audio amplifiers" lots of new products

GaN400

Power Amplifier

$2,999.00

 

 

GaNFET Technology
• 400 watts per channel 
• Drives any speaker 
• Fully balanced topology 
• Balanced and unbalanced inputs 

 

https://www.peachtreeaudio.com/products/gan400

 

Nice explanation from Peach Tree

What is GaN?

The GaN400 achieves new levels of performance and efficiency by utilizing GaNFETs instead of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) that have been the industry standard for more than 50 years. MOSFETs revolutionized the electronics industry in the second half of the 20th century and have become the most common transistor in electronics and the most widely used semiconductor device in the world! Their significance in the electronics industry and the other industries that rely on them can’t be understated. However, over the years, the rate of MOSFET improvements leveled off as the performance got closer and closer to the theoretical limits of the materials and processes. The need for something better grew. Enter GaN.

 

GaNFETs started to gain attention over the last decade as audio engineers and designers realized that they were suitable for high frequency, high voltage, high temperature and high efficiency applications especially when compared to their MOSFET counterparts. GaNFETs turned-on ~4 times faster and turned-off ~2 times faster reducing switching distortion (ringing) by several orders of magnitude. This, in-turn, allowed designers to use much less global negative feedback to achieve excellent measured results. The result is an amplifier with exceptional musicality and excellent measured performance. In other words, an amplifier that provides wonderfully natural sounding music reproduction like the best tube amplifiers, yet retains the tight bass, extended frequency response and sheer dynamics of the best solid- state amplifiers. It really is the best of both worlds and all of this is accomplished in an amplifier that is also one of the most efficient designs in the market today converting ~96% of the electricity from the wall into usable power.

The Importance of the Power Supply

Every power amplifier is dependent on its power supply to provide the power reserves necessary to drive the loudspeakers at any volume level. The GaN400 is no different and it utilizes an impressive 850-watt RMS regulated power supply. This supplies the output modules with all the clean power they will ever need - even when things get really loud. The power supply uses the best parts available to ensure high performance, durability and long-term reliability.

[michaelwjones]

4 hours ago, Bubo said:

 

This one is Korean

https://www.crutchfield.com/S-3h5jpiPRM59/p_358RA180/HiFi-Rose-RA180.html?

 

 

Wow; I have some butt-ugly equipment, but I think that one may win the prize in my book. I'm glad they run cold; I'd have to throw a blanket over it.

[Khornukopia]

16 minutes ago, michaelwjones said:

I'm glad they run cold; I'd have to throw a blanket over it.

It looks like a fancy 8-slice toaster. 😄

[Khornukopia]

23 hours ago, Bubo said:

Starting to see GAN FETs in new Amp designs

I hope to have one someday. A while back, someone posted a picture and info of a GAN FET encased inside a glass vacuum tube and built onto a "tube" amp chassis. It was interesting.

[billybob]

Reminds me of the gallium arsenide fets used in the low noise amplifiers  from the space communication days.

Could be parametrically cooled.

Cool...

[michaelwjones]

34 minutes ago, Khornukopia said:

I hope to have one someday. A while back, someone posted a picture and info of a GAN FET encased inside a glass vacuum tube and built onto a "tube" amp chassis. It was interesting.

 

Several years ago, KR Audio (aka Kron) made an amp with a transistor inside a vacuum tube. I was close enough to buying one that I emailed Kron to see if replacement "tubes" was available and they are.

[michaelwjones]

46 minutes ago, Khornukopia said:

It looks like a fancy 8-slice toaster. 😄

 

If form follows function, I'm scared.

[Islander]

Sure, that amp looks like an 8-slicer at first glance, but on looking closer it reminds me of something from Nagra, that Swiss manufacturer best known for high end portable tape recorders.  The inset Input selector is Nagra style, and so are the yellow VU meters.  Other than that, the Balance slider is kind of cool.  On most modern gear, it can be complicated to adjust something as basic as the Balance, often requiring you to dig into a menu or two, so that’s a welcome and very convenient change.

 

Other than that, the reversed-comma shape of the Pure Direct switch is a bit whimsical, and the geared Volume control and display is amusing and intriguing, at least to me.  Who knows, maybe that is a better kind of Volume control?

 

Of course, how it sounds it the most important thing, but its looks wouldn’t make me hesitate for a second to put it on a shelf in my system.

[pzannucci]

Would love to have one of these:

 

https://www.stereophile.com/content/technics-su-r1000-integrated-amplifier

 

[Bubo]

2 hours ago, pzannucci said:

Would love to have one of these:

 

https://www.stereophile.com/content/technics-su-r1000-integrated-amplifier

 

As the chip set production ramps up

the cost per watt should begin to fall

Especially if RIAA GAN chip sets etc hit the market

Low end systems will be 4-5 chip sets with mfg firmware mounted on a PCB

like the low cost Class T, D products we see now

[Bubo]

What is quantization error and how does signal to noise relate to this?

 

Question :

What is quantization error and how does signal to noise relate to this?

Answer :

Quantization error is the difference between the analog signal and the closest available digital value at each sampling instant from the A/D converter. Quantization error also introduces noise, called quantization noise, to the sample signal. The higher the resolution of the A/D converter, the lower the quantization error and the smaller the quantization noise. The relationship between resolution (in bits) and quantization noise for an ideal A/D converter can be expressed as Signal to Noise (S/N) = -20*log (1/2^n) where n is the resolution of the A/D converter in bits. S/N is the signal to noise and is expressed in dB. This relationship can also be approximated as S/N = 6*n. Typical S/N ratios for ideal A/D converters are 96dB for 16 bits, 72dB for 12 bits, and 48dB for 8 bits.

https://www.tek.com/en/support/faqs/what-quantization-error-and-how-does-signal-noise-relate

 

Good explanation of how a DAC works

The phono GANFet in the Panasonic above is an A-D converter

note the saw tooth diagrams

https://www.tek.com/en/blog/tutorial-digital-analog-conversion-r-2r-dac

 

What are aliasing errors? Are they hard to detect?

Answer :

An alias is a false lower frequency component that appears in sampled data acquired at too low a sampling rate. Aliasing errors occur when components of a signal are above the Nyquist frequency

 

(Nyquist theory states that the sampling frequency must be at least two times the highest frequency component of the signal)

 

or one half the sample rate. For example, if you are acquiring data from eight channels at 100k samples/second, the sampling rate for one channel is 100 ksamples/second * 8, or 12.5 ksamples/second. In this case, any signal component with a frequency above 6.25 kHz will cause aliasing errors. Aliasing errors are hard to detect and almost impossible to remove using software. The solution is to use a high enough sampling rate, or if this is not possible, to use an anti-aliasing filter in front of the analog-to-digital converter (ADC) to eliminate the high frequency components before they get into the data acquisition system.

 

My comment:

CD eliminates everything above 20Khz

If you can't hear it, does it need to be there

amp designs that can't handle high freqs have TIM distortion

Something about Nature, it all works together in a unified system

[pnort]

https://eepower.com/technical-articles/how-gan-fets-have-become-the-technology-of-choice-for-audiophiles/#

How GaN FETs Have Become the Technology of Choice for Audiophiles

November 29, 2021

 

The noise spectrum is the biggest issue. GaAs devices had a lot of low frequency (1/f) noise. Data in this article suggests that GaN has less than silicon devices. Of course it depends upon what type of device is used-- bipolar, MOSFET, or jFET. I don't know the details on that question.

Generally GaN would be used in cases where high power is important. Not particularly the case for high-efficiency speakers.

I'm personally enjoying Western Electric 300B tubes in an Elect 8600S. Three clicks of the volume and I'm there in spite of being "hard of hearing".

[Marvel]

On 7/18/2022 at 6:28 AM, Islander said:

Sure, that amp looks like an 8-slicer at first glance, but on looking closer it reminds me of something from Nagra, that Swiss manufacturer best known for high end portable tape recorders

A LOT like the finely machined Nagras. I believe Dave Mallette (RIP) would have approved.

[Marvel]

And Nagra makes peamps and amps, too.

 

[Islander]

You can see that Nagra has consistent styling.  That amplifier looks different, in the knobs in particular, but they’re similar enough to the classic models that you can see the family resemblance.

 

The prime example of stylistic consistency would have to be McIntosh, with their big blue meters.  They’re usually power meters, but on the MT-10 turntable, the big blue meter shows the rpm.  Not much excitement watching that meter.  According to one McIntosh company person, the various components look similar enough that you can slip a newer and more expensive unit into your system without your spouse noticing.  He may have been joking, but it’s very plausible.