The Peachtree Gan 400 Power Amplifier uses GaNFET technology within its splendid design — Douglas Moore gives a detailed account.
There have been technologies over the years that have arrived before we understand how to take advantage of what they can do. When the CD first came out digitized music was a fairly new technology. Companies rushed to develop CD players to compete with each other while using the technology that was around at the time.
Both studios and electronics manufacturers had limited knowledge of this format and didn’t take full advantage of it. Studios tried to do what they always did when they recorded in analog which in most ways did not utilize the advantages of digital audio. As time went on both the studios and electronic manufacturers learned the technology and how to get the most out of it and today digital audio is the prime format for music production and reproduction.
Whereas new technologies are always great they are not at their best out of the gate and need time to be honed and studied to get the most from them. Class D amplifiers are a technology that was invented in the 50s but was relegated to use in small audio products where ultimate sound quality was not as important.
By design, Class D amplifiers produce less heat but inherently work more efficiently than Class A or A/B designs. While class D was used in products like hearing aids and small radios being both more efficient and light they were not acceptable in music production or reproduction as they had issues with the transistor technology of the time. The germanium-based bipolar transistors available in the ’60s were not consistent enough and too limited in performance to allow class D to function well enough for audio component applications. It wasn’t until the 80s and 90s that the newer silicon-based MOSFET transistors evolved into a consistent, fast, and inexpensive way to bring this amplifier topology to the mainstream.
While the new MOSFET transistors gave new life to this technology, these new amplifiers were relegated to use in things like small stereos and all-in-one home theater systems. The aforementioned amplifiers had issues with switching speeds that were too close to the upper frequencies needing filters to do away with any switching noise in the audio band. This can affect the quality of the amplifier’s high frequencies and make them strident.
Due to these limitations, class D amplifiers were seen in powered subwoofers and bass applications that would not suffer the audio effects of the higher frequencies. There were a few early examples of class D in high-end audio but were not well received due to the perceived brittleness in the highs and higher distortion from the silicon-based MOSFET switching devices in these amplifiers.
Although Gallium Nitride has been around for a long time being discovered in the 1800s using it in transistors for audio is relatively new. Switching speed and loss during the switching itself were the main drawbacks to Class D. Engineers discovered that using gallium nitride-based transistors showed a faster and cleaner switching speed with fewer losses than silicon-based transistors.
I have tried over the years to embrace class D amplifier technology only to be let down by the sound quality of these amplifiers. Using class D amplification to power subwoofers as well as high-power applications was loud, light, and did not overheat which was of prime importance. But every time I would try out a class D amplifier in my main system I gave up and went back to my class A/B amplification.
When I started hearing about this new transistor being used in class D audio applications I was intrigued, to say the least. This faster and cleaner switching technology promised to take class D amplifiers to the next level and put them on par with conventional amplifiers on a sound quality basis. I contacted Peachtree Audio as their GaN400 amplifier uses this technology and would let me hear for myself if this newly implemented transistor could take things to the next level.
Peachtree is a brand that has been making quality audio products since 2007. Founders Jim Spainhour and David Solomon who are veterans of the audio world saw that many of the high-end audio companies were not paying enough attention to the movement of computer-based audio that was taking place then. So while other audio companies were business as usual Peachtree was busy designing products that would fit in with this new movement.
The Decco was Peachtree’s first product and was the world’s first to include a USB input. This USB-based DAC inside the Decco allowed listeners to connect their computers to the amplifier directly to allow playback of files from a hard drive. People started seeing that music downloads and CD rips were much easier to manage and play from their computer while the Decco made this playback plug and play.
Meet the Peachtree GaN400
While Peachtree has been mostly associated with integrated amplifiers they have come out with an assortment of pre and power amplifiers over the years. The GaN400 and GaN 1 are their newest models that utilize this GaN technology.
The GaN 1 is a fully digitally controlled amplifier that is geared toward people who are going to be using a variable volume streamer like the Bluesound Node to get all of their music. Peachtree asked me if I would be more interested in reviewing that piece since it is the newest. My system comprises both vinyl playback and digital playback chains so the GaN400 seemed to be the better fit with my system and playback needs. While the GaN400 represents their top analog power amplifier technology Andrew Clark from Peachtree told me that their GaN1 power and Carina GaN integrated amplifier feature a zero-negative feedback full digital design that promises even higher performance.
Setup and Build Quality
The GaN400 was double-boxed and came with a manual and a pretty hefty power cable for a factory cable. I did not use this cable as I have high-quality power cables in my system already so I left it in the box but I must say this factory cable is much better than what a lot of companies send with their products!
Looking at the GaN400 it is easy to see the attention to quality here. From the aluminum front panel and top vents(they have a cool gunmetal look to them) to the real wood cabinet finished in a very high-quality Gloss Ebony Mocha(piano black is also available). In the looks department, Peachtree was able to stay true to its roots while also providing a product that looks good enough to put in any system.
Installation was very simple as I used my Iconoclast XLR and speaker cables to connect up the GaN400. The GaN400 is a fully balanced design so a Balanced connection theoretically will give the best performance. The balanced connections have push-button releases on them which I prefer over the friction-hold connectors you find on lesser products. There are also RCA connectors should you need them.
The speaker binding posts are high quality and may accommodate banana or spade connectors. Since class D amplifiers cannot use the ground of the high-level connection on the negative speaker connector, Peachtree added a copper thumb screw to the back panel so that I could ground my high-level connections to the REL subwoofer in my system. I appreciate that there is plenty of room for all the connections, which makes installation simpler. Many amplifiers swarm the connections and force the cables to cling to one another. This is a side effect of Peachtree’s decision to somewhat expand and disperse the circuits of this 15.25-pound amplifier.
There is a main power switch on the back panel as well as a standby button on the front panel to power up the amplifier. After turning on the mains power and pushing the standby button I was fully powered up and ready for action!
Since this was a review sample and had been used before, I was not as worried about break-in as I am usually with brand-new amplifiers. But just to be sure I ran the GaN400 as my daily driver not taking things too seriously for a couple of weeks. Seeing that I have a questionable history with class D amplifiers I had to put my mind on reset and allow myself an open mind concerning this new amplifier technology.
Nnenna Freelon’s 2003 album “Live” is an excellently recorded album with all the attributes you can attribute to a live recording. This is an album you have to play all the way through with all songs featuring great recording techniques and musicianship. From the bass guitar to the vocals and drums this album gives a beautiful live setting and gives a level of musicality that is thoroughly enjoyable. When I hooked up the GaN400 and played this album I was surprised at the performance.
For the first time, I was listening to a class D amplifier that didn’t let that fact be known by its sound reproduction. The GaN400 showed the excellent soundstage in full glory and allowed the imaging to place instruments in their respective locations on the stage. The GaN400 allowed me to hear all the macro dynamics in the music without any brightness or fatigue. Bass was detailed and deep allowing this album to anchor its foundation in my room.
Hayley William’s 2020 album “Petals For Honor” is one of a few popular music albums today that take the studio mixing and matching seriously and it shows. She has excellent music-writing abilities and can put together songs that deliver her message.
Listening to the track “Sudden Desire” the GaN400 allowed the beginning bass guitar lick to shine with good instrumentation and prowess. Bass not being an issue with most class D amplifiers this wasn’t surprising but what was interesting was the way the vocals were cleanly delivered showing Hayley’s great voice. The chorus of this song has a cool vocal display that will test your system’s ability with soundstage width. The GaN400 delivered a great soundstage allowing this track to shine. The Treble also sounded silky and did not have the hardness or brightness I had heard before in class D designs.
The song “My Friend” is a great track that has both a soft starting and soothing start transitioning to a more driven chorus, The GaN400 allowed me to hear these contrasts fully and let the song show its sensibilities. Again Heyley’s vocals have great body and allowed me to hear the emotion in her voice. The track has a post-chorus section that has some jazz-style elements that give the song substance.
There is a deep bass hit in this post-chorus that allowed me to fully hear the GaN400’s bass prowess. Without a hitch, the deep bass poured from the track and gave both my main speakers and REL subwoofer the workout they love. Being that my Spatial Audio speakers are 94db efficient they require a lot of power to run but when the music gets dynamic, especially in the bass the 4 15” woofers can tax an amplifier’s dynamic headroom. With 400 watts per channel RMS from either 8 or 4-ohm loads, I never felt the GaN400 was sweating or running out of power. It just delivered what I threw at it at all the “sane” volumes that I played the music. I think the GaN400 could power about any speaker on the market in its class without coming close to its limits.
Being that my reference Pass Labs X150.5 is a well-regarded class A/B design it was interesting to compare it to the GaN400. The X150.5 is no longer sold by Pass Labs but still has quite the following for sound quality so I wanted to see how this new class D technology could compare.
Playing the Nnenna Freelon’s tracks back on the system with the Pass amp had the same level of detail as the Peachtree but was even more holographic allowing instruments and vocals to float on the stage in their places. Vocals sounded less sharp with the Pass amplifier but also were less peaky showing better vocal balance.
Soundstage depth was also another area in the Pass that had an edge but not by much as both showcased great soundstage and image depth. Also, dynamic swings were more apparent with the Pass amp. For me, this was to be expected as the Pass Labs is in a whole other price class than the GaN400.
For its price, the GaN400 does do a good job on these metrics but not quite at the X150.5’s level. The Pass labs also allowed the music to have a more realistic tone and body to the music. One area in which the GaN400 put up a greater fight was in the bass. While the Pass was punchier in the bass with bass drum hits having just a bit more impact, the GaN400 had an edge in bass depth of tone and intricacy. This was an impressive showing knowing the price difference in these amplifiers.
Treble was one area I wanted to pay close attention to as it is one of the main areas of contention with class D amplifiers from experience. With the GaN400 the treble was detailed, vivid, and quite smooth. The only time things got too hot up top was when the studio work on the album either mixed hot or was not great to begin with. When I played songs I knew were bad recordings or mixed improperly there were times the GaN400 could sound splashy compared to my reference Pass amplifier.
While the GaN never took on a fatiguing or grating nature, the Pass was able to forgive bad recordings a bit better than the Peachtree. Both amplifiers showcased drum cymbals with great specificity and smoothness on good recordings. The GaN400 appeared to have more speed with cymbals and brushes but the Pass gave cymbals and brushes a more realistic sound.
The midrange was great on both amplifiers and allowed me to hear all of the instruments in the mix. Again the GaN400 was the more energetic of the two having a drive to the midrange while the Pass labs had the same level of subtleness but produced the music differently. With the Pass Labs, the piano was fuller with more body to this large instrument. Guitars and horns sounded equally as satisfying on both amplifiers with the GaN400 having the edge in transient impact offering an energetic tonal quality. The Pass had good characteristics as well in the area but prioritized tonal richness and fleshiness.
I will sum up my comparison with this: The Pass is the more refined and grown-up amplifier of the two while the GaN400 is the more dynamic amplifier giving out lots of exhuberance but not being as forgiving with bad recordings. The Nenna Freelon tracks took on a boldly driven sound on the GaN400 while these same tracks had a relaxing and soulful presentation on my reference Pass Labs. These differences are important in that proper system matching will allow the user to fittingly differentiate between the two units.
I have enjoyed my time with the Peachtree GaN400 and think it is an excellent amplifier in its price class. It has changed my mind on class D amplification and look forward to what will come of this technology in the future.
The GaN400 had a dynamic, zestful presentation that was neither fatiguing nor tiring over long listening sessions. It has more than enough power for about any speaker out there to be driven at all sane volumes, and it weighs only about 15 lbs. which is a heck of a lot easier to move than my heavy Pass Labs amplifier.
There are a few areas in which my reference Pass amplifier was better but I expected that seeing that these two are in different price classes. Depending on the system and speakers you might benefit from the more energetic approach of the GaN400. In its price class, I cannot recall too many amplifiers that give you this level of power, detail, energy, imaging, and soundstage ability. Having all of this come from a visually appealing 15 lbs. amplifier is pretty amazing. I can’t wait to hear the GaN1 or Carina GaN amplifiers to see what a zero negative feedback GaN design can do! If you are in the market for a high-powered amplifier in this price class I recommend giving the Peachtree GaN400 a listen and see if it will impress you as it did me. Highly Recommended!
Review System: Speakers: Spatial Audio M3 Turbo S open baffle./ REL T9x subwoofer/ Digital: Denafrips Venus II, / Modified PC-based Music server/streamer. Analog: Pro Ject X2 B Turntable, Darlington labs MP-7, and SU-7 phono preamp, Audio Technica AT33 PTG/ii cartridge Amplification: Hegel P20 preamp. Pass Labs X150.5 power amp. Conditioner: PS Audio Quintet. Cables: Iconoclast Series 2 SPTPC speaker cables, Iconoclast Generation 2 ETPC XLR cables and Gotham 4/1 RCA interconnects, Iconoclast BAV REL subwoofer cable
Peachtree GAN 400 Power Amplifier
Peachtree Audio ~ 2045 120th Ave NE, Bellevue, Washington, 98005, United States
(704) 391-9337 https://www.peachtreeaudio.com
WHERE the MUSIC BEAT meets the AUDIOPHILE ELITE !
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