The Mini GaN 5 monoblocks (with WBT binding posts) hit 150 hours of break-in this morning, and the sound opened up and relaxed a bit more. Although further improvements may come, I think there is plenty to comment on at this point.
In brief, the Mini GaN 5 monoblocks are better in every respect than the Pass Labs XA-25, and I plan to happily keep them.
Room and equipment: The room is 18’ x 14’ and I sit 8’ from the M3 Sapphires which are 8’ apart and 3’ from the wall behind them. Roon ROCK NUC --> Anticables USB --> Holo May KTE DAC --> Anticables XLR --> Holo Serene KTE Pre-amp --> Anticables XLR --> Mini GaN 5 Monoblocks --> Anticables Level 4.2 Flex speaker cables --> Spatial M3 Sapphires.
Break-in: Turning the amps off for at least 30 minutes twice per day seemed to help break-in noticeably. I’ve seen amp manufacturers comment that letting the capacitors charge, run, and discharge helps them settle in. It seems to be the case with these amps as well. In the first 80 hours, the sound was vivid and revealing, but after 80 hours it became more cohesive, and each day after the 80-hour mark the sound has opened up and relaxed more without losing the exceptional resolution and tone. I don’t know that break-in is completely done, but it is on par so far with other amps I’ve had. With highly resolving speakers like the Sapphires, the changes are substantive during break-in.
[N.B. All listening was done with the dB matched using two reference tones and a stand-alone dB meter. This resulted in turning down the pre-amp from -28 to -39 going from the XA-25 to the Mini GaN 5s. After early break-in at the medium gain setting, I adjusted the Mini GaN 5s to the low gain setting, which is only 2 dB less than the medium setting. There seems to be no reason to use more gain than the lowest setting with the M3 Sapphires.]
Sound: The Mini GaN 5 monoblocks seem to be the best amps that I have heard in any system that I have owned, but I can only legitimately compare them to the Pass Labs XA-25 and, indirectly, to the Benchmark AHB2 that the Pass Labs XA-25 replaced. The XA-25 provided more detail and bass extension and texture/resolution than the AHB2. The XA-25 was, to put a meaningless number to it, 40% better than the AHB2. The Mini GaN 5 monoblocks are 80% better than the XA-25: the step up from the XA-25 to the Mini GaN 5 monoblocks is twice as significant as the very clear step up from the AHB2 to the XA-25.
Across the board, the Mini GaN 5 monoblocks are exceptionally resolving: a clear and natural portrayal of details in every track I played, without any hint of tipped up treble creating just an illusion of detail. The sound is not at all fatiguing, and the instruments have realistic body and timbre. The ability of the amp to keep track of every detail in the recordings leads to benefits in the range of things that make music alive and palpable: timbre, soundstage depth and width, harmonics and transients, bass heft and texture, and musicality.
Compared to the XA-25, bass with the Mini GaN 5’s is more textured, controlled, slightly deeper, and realistic. In listening to jazz, for example, there were several instances where I heard for the first time the musician bending the strings on the upright bass to shift the note. It’s a revelation to hear those kinds of subtleties that bring you closer to the live performance. This happened repeatedly. I could track deep bass from beginning to end in songs where it had previously seemed to be there only in one or two passages. And in recordings with a lot of well-recorded bass, like the American Beauty soundtrack, the Mini GaN 5’s provided better tone and more texture than the XA-25. It was not even close.
In the midrange the Mini GaN 5’s provided the subtlety of detail that makes vocals palpable and real, and, depending on the recording, intimate. In comparison, the XA-25 has a bit of sheen in the vocal range that tends to mask the finest subtleties and make some vocals a bit dusted in grit—a very fine grit, definitely, but when it is gone the absence is quite noticeable. The ability of the Mini GaN 5’s to reveal details in the recording gives instruments a very real and natural timbre and conveys the three-dimensional sense of the instrument having a shape and body better than the XA-25.
The Mini GaN 5’s certainly have nothing to do with thin, dry, or clinical sound. The Mini GaN 5’s add no brightness to the upper midrange, and they improve on the XA-25s in playing recordings that may have some inherent brightness. By cleaning up the subtle hash or grunge in the sound, the brightness in some recordings becomes more musical and less offensive.
In the treble the Mini GaN 5’s resolve things that are a bit confused and fuzzed by comparison in the XA-25. On one jazz recording, the sound that I had always assumed was a bit of hiss on the analogue tape turned out to be the drummer brushing on a snare off to his right. This sort of revelation was commonplace as I listened to hours of music that I was familiar with. Never once was the treble harsh or fatiguing, and, like the bass and midrange, I found surprises in new details in track after track.
The soundstage and imaging are both exceptional. The Mini GaN 5s are able to reproduce the fine spatial cues that allow the Sapphires to define a deep and wide soundstage when it is in the recording. The Sapphires disappear easily, and instruments extend back several feet and beyond the left/right edges of the speakers. The image is very stable, and the focus allowed me to see a musician, like a saxophone player, moving on stage. He was not just playing 3 feet deep and 2 feet in from the left speaker—he was moving side to side a couple of feet during his solo. Compared to the XA-25, the soundstage and imaging from the Mini GaN 5s simply opened up a new level of natural realism.
The exceptional, natural resolution of the Mini Gan 5’s allows the communication between musicians to come through more clearly. Being able to hear the string section in an orchestra have a call and response with the woodwinds buried deeply in the recording is the kind of thing that makes the Mini GaN 5’s such a revelation. The technical promise of higher switching speed in a GaN FET does not appear to be just something for electrical engineers to appreciate on a spec sheet or the test bench. It’s not just an issue of reducing the size of the device or significantly improving efficiency or lowering costs. GaN FETs, or at least this implementation of them, do seem to open up new horizons for reproducing real, palpable music still hiding in recordings, even those from more than half a century ago.
I don’t know how much more one would have to spend to get a better amp than the Mini GaN 5 monblocks. Perhaps the AHB2 and the XA-25 were not optimal matches to the Sapphires, and there are other Class A or Class A/B amps in the $3-5k price range that are on par with the Mini GaN 5’s. It seems unlikely, however.
I think the limiting factor at this point could be the M3 Sapphires. The AMT mid/tweeter and faster bass/sub drivers in the X series could possibly allow even more of the music from the Mini GaN 5 monoblocks to come through. The M3 Sapphires sound glorious with them, however, so it’s not a serious concern at this point.
