It began with a bad outlet. Perhaps two weeks after my husband and visiting friend created several delightful holiday light displays in the living room, one of the living room outlets died. Every time I tried to plug in part of the light show, it, along with the living room sound system and reading lights, lost power. If the Grinch didn’t exactly steal Christmas, he sure tried to guarantee it would arrive silently under the cover of darkness.
Evil Grinch proved no match for the visiting electrician. While our savior was here, I tapped his knowledge of the eccentricities of Port Townsend’s electrical grid. When queried about the underground wiring to our house from the transformer across the street, he said, “Given the age of your house [1992], I am more than 99% certain that the wiring to the meter and your breaker panel is aluminum.” After opening the panel, he shattered all illusions by declaring that the underground wiring from the main house to the second breaker panel in the detached music room was also aluminum.
What? Back in the spring of 2015, when we designed the music room, I spent a lot of money installing a dedicated line with two legs. One led to a single AudioQuest duplex outlet and a second, on a different breaker, led to a double-duplex AQ outlet, with four receptacles. We used 10-gauge copper conductors in metal-clad cable, the hot, neutral, and earth ground conductors twisted around each other instead of running parallel as they do in typical cable (think Romex). Twisting the conductors helps with common-mode noise cancellation, the grounded metal sheath shields noise, and the large, 10-gauge conductors reduce the resistance of the circuit. Nearly eight years later, I’d discovered that my entire dedicated line was fed by aluminum, which is notorious for adding noise to the line and muddying bass (footnote 1). No wonder that time and again, amplifiers sounded smoother, warmer, and more musical when they were plugged into an AudioQuest Niagara power conditioner or Stromtank battery power source rather than directly into the wall.
Knowledge is power when it leads to action. I moved fast. Distributor Wynn Wong would arrive from Toronto in less than a month, to install two Serbian-made Karan Acoustics POWERa monoblocks ($106,000/pair) for review. These monoblocks weigh an astounding 231lb each, with a shipping weight of 286lb; each contains two 2700VA toroidal transformers and a 210,000µF bank of custom capacitors. Each monoblock requires two 15A power cables, one for each amplifier stage.
I doubted that the Stromtank S 2500 Quantum MKII was equipped to handle such a big power draw while conveying the full dynamic capabilities of these amplifiers (footnote 2). I needed a viable alternative; there was no way I was going to compromise sound quality by plugging the POWERa’s into outlets mostly fed by aluminum wiring.
First, Hans Frederickson of Frederickson Electric—a man (and a company) that understands the needs of audiophiles—made room in his schedule for the two-stage wiring upgrade. Second, Wong agreed to travel to Port Townsend and install the amps with his assistant, Kenneth, ensuring that David and I would not be crippled for life by our attempts to haul them into place. Wong also agreed to bring a 6-outlet Acoustic Revive RTP-6 Absolute power box to help plug everything in.
Before electrical work began, I enlisted the assistance of power expert Ed DeVito of Audio Ultra in Sumner, Washington, near Seattle. I also consulted Garth Powell of AudioQuest. Rather than go with Audio Ultra’s full AU3000 power package, which would have necessitated more electrical and structural changes than time and bank account allowed, we took a more modest approach. We replaced the music room’s existing breaker panel with a Square D QD 100-amp subpanel that uses bus bars of tin-plated copper (footnote 3) rather than aluminum. We added a UL-approved EP2050EE surge protector/noise filter from Environmental Potentials, Audio Ultra’s affiliate company, to provide, in Ed’s words, “non-sacrificial protection from transient voltage surges and spikes” and to “optimize system performance by absorbing … noise between 3kHz and 1MHz without shunting energy to ground.” (footnote 4) We tested grounding, examined panel loads, and ensured that we met Ed’s specifications as we created two in-phase 20A branch circuits to feed the audio system’s dedicated outlets. Having two circuits allowed me to separate the amplifiers from the front-end components. We could do nothing about the aluminum wiring that ran underground from the transformer across the street to our meter, but most everything else was changed.
Some of this work took place two weeks into the review. The listening report that follows covers sessions conducted after everything was in place, settled in, and performing optimally.
Previewing the main character
What is this beast of an amplifier? Here’s what I can share about the POWERa, from information provided on the Karan Acoustics website, by distributor Wong, and responses to questions sent to company founder and chief designer Milan Karan in Novi Sad, Serbia.
Karan, 57, initially made his living designing “sophisticated medical equipment” while building audio equipment on the side “just because of my passion for music.” A guitar player for the joy of it, he created Karan Acoustics in 1986 after his musician friends kept saying “good things” about the amplifiers and preamplifiers he had built. A music lover who tests his equipment with all kinds of music but prefers live jazz and classical, Karan regularly attends concerts during travel to other cities and countries, and his nine employees are all music lovers who listen to designs together and compare prototypes, testing out small changes.
Karan Audio has been distributed in Europe and Asia for more than 25 years. North American distribution began five years ago after Karan met Wynn Wong.
“My goal was to make the POWERa the best sounding amplifier, without compromising anything,” Karan wrote in an email. “I wanted to achieve a natural sound as close as possible to live music and build an amplifier that would not change the input signal in any way, … just deliver a lot of power to ensure there is enough headroom to drive any speaker while providing air/transparency, separation among the instruments, etc.”
Karan began designing his top-line Master Collection (topped by the POWERa) 10 years ago. “It’s a huge, cost-no-object step up from its predecessors,” he continued. “I put everything I learned from 30 years of medical and audio engineering into it.
“I would love to make the POWERa lighter without compromising the sound, but it’s otherwise impossible to achieve a high output power capability like its 2100W into 8 ohms, 3600W into 4 ohms, and 6000W into 2 ohms.” (footnote 5) Peak power is even higher, at 2400W into 8 ohms, he noted. “The weight comes from a high quality chassis with good acoustic and vibration isolation, overbuilt internal heatsinks, and high current/low-noise transformers. To achieve a natural, precise, focused, dynamic sound, the heatsinks are designed to eliminate acoustical and vibrational feedback to electronic components. You cannot have dynamics if the vibration affects the sensitive components. The PCBs are decoupled with a special kind of spacer and copper discs to allow the musicality and harmonics to flow.”
The POWERa neither runs too hot to touch nor heats the room to an excessive degree. As Wynn Wong explained, “Karan amps may be class-A, but they don’t run hot like traditional class-A amplifiers, which run a constant high bias. Because of the POWERa’s ‘sliding class-A bias circuit,’ the bias level is adjusted based on the signal (from the preamp) in real time.”
“The design is fully balanced, very high speed, and extremely quiet,” Karan wrote. “I used the best possible components; some are custom-made for my company. I also selected the best PCB conducting and isolation material. The thickness of the copper on our PCB is much higher than usual. I tried many samples of different thickness and chose the right one by listening. The design of the PCB, the architecture, and component placement also affect the sound. I had to make small adjustments to further improve performance and ensure that components would not interfere with each other.”
One of the POWERa’s unique features is “a proprietary, in house designed, built in Line (mains) Conditioner.” (footnote 6) Activation is by a toggle switch located on the bottom center of the rear panel, directly below the speaker cable outputs and the single-ended and balanced inputs. Counterintuitive though it may seem, power conditioning is engaged when the switch is in the “0” position and disengaged in the “1” position. (It’s the opposite turning the amps on and off.) Karan claims the Line Conditioner acts in part as “an efficient DC ‘eliminator’,” and that its rating of 60A or more can cater to “at least three times more” than the maximum current and voltage flow required from the main power supply.
Each POWERa contains two toroidal transformers, one for each amplifier stage; each requires its own 15-amp power cable. Their IECs are located on each side of the rear panel, each beneath its power switch. There is no standby button. Asked the rationale for this two-cable, two-switch design, Karan replied, “It’s not possible to connect two big transformers to one switch/fuse because they draw too much current. We did a comparison, and it sounds much better with two switches/power cords, one for each stage.”
The POWERa’s front consists of a central black glass panel on which the Karan logo and name are tastefully and moderately illumined in red. Flanking the black glass are silver-colored aluminum panels. The buffed silver aluminum top continues the front’s geometric layout, with a large logo engraved in the center flanked by panels covered with small, heat-releasing holes. The CS2M footers, too, are “safe,” being tall enough to enable the amp to be lowered and raised without crushing your fingers. Hernias are another story.
I asked Karan what setup he considers optimal. “The amplifiers will sound noticeably better with amp stands, but you still get decent sound placing them on the floor,” he replied. “The CS2M footers are the latest model from Critical Mass Systems. Wynn distributes Critical Mass Systems, and he suggested a few years ago that I try their footers. They have greatly improved the sound.”
Karan is currently developing prototype speakers that include a matching sub tower with active crossover. It takes six POWERa mono amplifiers to drive them. Prepare your mansion now!
Footnote 1: From a practical perspective, the main problem with aluminum wiring is that, because its resistivity is higher than that of copper, it heats up more than copper does, and when it heats up, it expands. Over time, this can cause electrical connections to lose integrity and fail. This led to many house fires in the late 1960s and early ’70s, especially in houses rigged with a certain aluminum alloy. Any 1992 installation performed by a qualified electrician should be safe. So what are the consequences of aluminum wire in a hi-fi system? Other than increased energy dissipation per unit length (for the same gauge of wire), I don’t know.—Jim Austin
Footnote 2: By email, Stromtank’s Wolfgang Meletzky confirmed that the S2500 Quantum MKII can deliver peak power up to 2800VA/3s. “If the continuous consumption is 12A or below then it is no problem with dynamics with 8-ohm speakers. If you are using a 4 or 2-ohm speaker, we recommend using a higher performance Stromtank like our S4000 Pro Power or our top model S5000 High Power.” The Wilson Alexia V’s nominal impedance is 4 ohms.
Footnote 3: Silver-plated copper is even better, but it costs substantially more.
Footnote 4: Translation: The EP2050EE helps filter out noise from appliances, heating units, computers, dimmers, LEDs, and more.
Footnote 5: Such a high power rating is not achievable with US household power, even if each of the two power cords is on its own circuit branch, with its own 20A breaker—that’s four circuit branches altogether—two for each monoblock, for amplification only. Karan specifies the input power at 115V, so the maximum continuous power, with two 15A power cords and two independent circuits, is 2 × 115V × 15A = 3450W per channel. If we assume that the amplifier can draw the full 20A, despite the 15A-rated IEC connector, then each monoblock is capable of putting out 4.8kW of continuous power.
Footnote 6: The quote is from the website. As I learned from distributor Wynn Wong while editing this review, the “power conditioner” in the Karan is really just a DC filter. No doubt, it’s a very well-executed DC filter.—Jim Austin
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