Bella Sound is the brain child of Michael Vice. Educated at UC Berkeley and Stanford in Physics and Electrical Engineering, Mike has poured his decades of experience and over 40 patents into his unique designs. Bella Sound's products include amplifiers, a power conditioner, and power cords, all based on Mike's conceptually novel approach, and married to the best parts and materials available. My first encounter with the company was at the 2022 Pacific Audio Fest displaying their power cords with Wells Audio, and again at the 2023 Pacific Audio Fest with their full suite of products.
The subject of this review, the Kahili Stereo Amplifier, designed by Mike with contributions from John Curl, is a dual mono design having separate right and left channel power supplies. Each channel also has separate power supplies for front end and output stages. The output stage utilizes neutralizing feed forward dynamic bias to reduce distortion without the need for high bias and massive heat sinks. Internal bandwidth is rated at over 500kHz. AC input is treated with Bybee Quantum Purifiers, transformers are cryogenically treated, and the power supplies utilize fast recovery rectifiers. I particularly liked the WBT binding posts, which are easy to hand tighten.
Visually, the Kahili shares its industrial design elements with its companion piece, the Hana power conditioner. I have the Hana in house, but will be evaluating it separately. The front panel has a conventional rectangular shape, but the top/side cover is curved on top and mirror polished. There is a band across the front with the company logo, and in the center is the on/off switch, which illuminates when activated. It's a beautiful amp with a bit of bling. Around back are the single ended and balanced inputs with a toggle switch between them to choose which. Each channel's connections are at opposite ends of the panel. Each associated channel's binding posts are next, with the IEC power input in the center.
Setup
Bella Sound sent me two Kahili amplifiers. To see a description of my system configuration, click on the link under my name at the top of the review. Each amp arrived in a huge box lined with six inch foam. Buried in the midst of all this foam was a Pelican flight case called The Vault, and bolted inside that case was the amplifier. According to my bathroom scale the empty flight case alone weighed twenty seven pounds, and combined with the amp was over one hundred pounds. Getting these beasts down into my basement listening room required the aid of my son and a dolly. Then, it was a matter of removing four bolts from each case and lifting the amps out.
In my system the Kahili amps, which are rated at 200-watts per channel into eight ohms and 400-watts per channel into four ohms, replaced my two Krell KSA 200S amps. The Krells are class A and rated at 200-watts per channel into eight ohms, but this is slightly misleading. The Krell amp is also rated all the way down to 1600-watts per channel into one ohm. It's been suggested that you could weld with this amp. I haven't tried that. An ideal amplifier would double its power with each halving of load. Going backwards from one ohm, that would mean 800-watts per channel at two ohms, 400-watts per channel at four ohms, and ending with 200-watts per channel into eight ohms. No amplifier can achieve this, so Krell essentially de-rated the eight ohm power rating to match this ideal. In reality the eight ohm power is closer to 300-watts per channel than 200. Krell has since discontinued this practice and, in fact, in my experience most amplifiers these days aren't even rated below four ohms in their specifications.
The owner's manual specifies that these amps need a 200 hour break-in. I was told that one of the amps was fresh from the factory and the other was a road amp that had traveled to numerous shows, etc. To start the break-in process I put the two amps on the floor and plugged them into a power strip. I turned them on and left them for over two weeks. While they were sitting there, I noticed that they ran slightly warm at idle. Though the manual doesn't say, I suspected that the amps were class AB but biased into class A for the first few watts. When I discussed this with Michael Vice, he confirmed my assumption about the amps class, and he warned me that my break-in method might not be sufficient and that the amps might require music signal to properly settle in. He was absolutely correct. When the amps were initially connected to my system, it was obvious that they still needed a lot of run in.
Two hundred hours of listening would be more than eight days if done all at once, which it wasn't. And so I sat through various listening sessions waiting for all the lumpy bass and squashed sound stage to evolve into a sonic butterfly. More than half the time I spent with these amps was waiting for the end of break-in. In fact, I think they continued to evolve right up until my last listening session. At one point during this period the amps went through a Jekyll and Hyde phase where sometimes they were beautiful and sometimes they were not. One never quite new which album the amps would like, although they seemed partial to Michael Jackson.
Listening
Once things started settling down the sound opened up and sweetened up. It's amazing how amps can sound so different from one another, and yet still make good music. The trick for the audiophile is to find the amp that makes your particular speaker sing. Synergy is real. The Bella Sound amps actually sounded similar to my Krells with minor differences. Soundstaging had good width and depth, but usually didn't extend forward much beyond the plane of the speakers. However, on occasion, with certain material, the amps would throw musical cues out into the room almost like a Q sound recording. I could never predict what material might do this.
Regarding Michael Jackson, I put on a 96kHz/24-bit download of Invincible, his last studio album. This was supposed to be a bit of a comeback album for Jackson as he hadn't released anything in ten years. It's not my favorite Michael Jackson. It lacks the vision of Thriller or Bad. A lot of the dance numbers seem almost too aggressive in nature with a bit of hard edge. One exception to that is the track "You Rock My World." The Bella Sound amps absolutely owned this track. They locked down the groove with uncanny grip and traction. The bass boogied hard and the music swept you away. Midrange was focused and the highs were extended.
Another demo track was Paul Simon's "Diamonds On The Soles Of Her Shoes" from a 96kHz/24-bit download of the 25th anniversary version of Graceland, a fascinating hybrid of Simon's songwriting and the mbaqanga music of South Africa. The male chorus that starts the cut fills the room with equal parts mouth, throat, and chest sounds. Then the instruments expand out into the soundstage, and I'm awash in the music. The Bella Sound amps portrayal of this was full, warm, and holistic, offering a thrilling reproduction of the event.
One more album that has been in rotation around here is a 48kHz/24-bit download of Marcus Miller's Laid Black. You don't realize that "Trip Trap," the first cut, is a live recording until the fade out when you hear the audience. The album effectively utilizes Miller's interesting blend of jazz, funk, soul, and hip-hop. This cut has a jazzy swing about it with Miller's bass center stage. The Kahili amps grabbed every funky bass note and pumped it out and everything swung hard.
During setup I had simply placed the Kahili amps in the system connected with exactly the same cabling that was used for my Krells. Bella Sound had provided their Kaula2 power cables, so once I felt I had a reading on the sound of the amps, I substituted the Bella Sound power cords. Chances are, if you hear this amp at a show or in a showroom, it's likely powered by its own Kaula2 cords. Although the inclusion of the cord brings the price of ownership to just $500 short of $30k, I suspect many purchasers of this amp with opt to include the cord, which is exquisitely constructed. There was an immediate synergy between the amp and the power cord. The basic nature of the amp was not changed but subtly sweetened and enriched.
Conclusion
At this price point, it should be possible to make arrangements with your dealer for a home audition. Just make sure the amp you try has been well broken in. This amp is a winner but only you can decide if it's right for you.
Beauty and performance, the Kahili amps have it all.
Kahili Amplifier
Retail: $24,000
Bella Sound
