Amp choice: Hovland, Karan Acoustics or Jeff Rowland?

July 18, 2017


I have long followed your reviews from the days of HiFi+ along with your pursuit of high-quality power amplification. I’m wondering if you are able to put in context for me your appraisal of three amplifiers I am considering on the used market. They are the Hovland Stratos, Karan Acoustics KA-M650 and the Jeff Rowland Model 625. Your reviews of each amplifier have been very positive, and all amps have at one time or another featured as your references in your own system. Looking back, how would you rate them in comparison?

I am using an Audio Research Reference 3 (I did not care for the sonic palettes of the Reference 5 or 5 SE). Cabling is mostly TARA Labs Air series, and I’m primarily running an analog front-end (SME 'table/'arm with Benz LP-S cartridge and Herron VTPH-2 phono).

Speakers are a good question! I'm currently running 1990s-vintage Hales System 2 Signatures (which have taken a lot of beating). They bear some resemblance to your favored Living Voice Avatar OBXR speakers: D’Appolito two-way with external crossovers -- very neutral and quite transparent, though a bit overdamped in the bass (but not terribly efficient and dip to below 3 ohms at 80Hz). Planned replacements are KEF 207/2s or one of the Verity Audio range.

I'm curious to also know if you think the big Karan amps provide better sonics than the smaller KA-S180 or just more "balls." My aim here is for amps that are not overly analytical or "in your face," but great at ambience retrieval and naturalness.

Did you ever hear the Halcro amps?

Keep on writing, Roy. After chucking out most of my old hi-fi magazines, I kept the classic TAS and HiFi+ issues.

Geoff Cosier

The amps you mention are individually superb; as you mention, each has spent considerable time in my system at one time or another. However, context is everything and once you start to factor in the demands of the speaker, specific circumstances and the wider system considerations, differences definitely start to emerge.

First, the Hovland Stratos. These are some of the best amps I’ve ever used, but also possibly the most elusive. I reviewed them when they first appeared and at the end of the review tried to buy a pair, only to discover that the company had folded. That means two things: there are very few Stratos out there and they are somewhere between difficult and impossible to get serviced. At least one serious listener that I know (an ex-Hovland distributor) is still using the Stratos -- and his stable includes some pretty impressive options -- but you need to consider the practical implications of ownership and the possible risk of total loss on your investment if they go US on you. I love this amp, but I’d hesitate to invest myself or recommend that you do so.

The Jeff Rowland Model 625: the only stereo chassis on your list, and a physically smaller amp than the other two as well. The 625 should be both more affordable and easier/cheaper to accommodate (half the rack, support and power-cord requirements). That makes it the budget option. However, despite its generous power rating, the 625 is not so happy with difficult or unusual loads (see the KEF Blade review for more on this). That’s where the speaker choice comes in. My experience with Hales designs is limited, but as I recall they were both low in efficiency and an awkward load. Were you using something like a Focal Scala v2 or a Vandersteen, I’d have no qualms at all. But with Hales and some uncertainty over what will replace them, I’d suggest that the 625 isn’t the ideal choice in this case.

Which brings us to the Karan KA-M650s, last but by no means least. The “smaller” Karan monoblocks (there’s also the massive KA-M2000) is a classic solid-state power house. It will (probably) drive a small car up a hill and is utterly unflappable. What makes it particularly interesting is that it doesn’t suffer from the rhythmic constipation and clumsy dynamics that afflict so many such designs. Instead, it is a fluid, articulate performer, long on resolution, locational precision and definition of the acoustic space. It will have no problems with the Hales’ electrical demands and will make the most of their wide bandwidth. The KA-M650 is a significantly more capable and more musical performer than the '180, largely as a result of the increased bandwidth and control. This improves dynamics, transparency, timing and dimensionality -- all of which help prevent the '650 becoming too stilted or analytical.

Now, let’s consider your preamp. The Audio Research Reference 3 is a legendary performer and rightly so. It throws a huge and vividly colored soundstage, with great dimensionality and fluid phrasing. More rounded and a little softer (especially at the bottom end) when compared to the later iterations, it has an enduring listenability and a smoothness that are often translated as "musicality." Thinking back, for many years Audio Research preamps were paired with Krell power amps -- to considerable musical effect. Given that both the Reference 3 and the KA-M650s mark huge advances in performance over those earlier products, I suspect that the pairing will be just as efficacious, but the results will be even more impressive. One word of warning, though: just with those earlier pairings, the DC-coupled power amps (or rather the speakers connected to them) will not take kindly to the switch-up/warm-up behavior of the tube preamp, so always let the preamp stabilize before switching on the power amps.

Finally, the Halcros: yes I’ve heard them and they’re not for me. I found them flat and sterile and the harder/wider bandwidth the speaker load, the greater the tendency became. I’d use any of the three amps you list in preference. -Roy Gregory

Qkore or Denali?

July 7, 2017


I must say I was somewhat surprised by the supposed improvements brought about by the Nordost Qkore grounding system. Are you saying that you experienced the aforementioned improvements even though you were plugged into the Shunyata Denali 6000T and 2000T? Shunyata has been the benchmark in lowering noise and backing it up with science and repeatable measurements. Can you clarify?

Jerry Belben

I had the Shunyata Denali units listed with my other equipment, because they are a reference that I use often. However, for my review, I used Nordost's Quantum power products with the Qkore system. I did this for two reasons, First, I wanted to keep the "loom" aspect intact, because I was using a full set of Nordost Odin 2 interconnects, speaker cables and power cords. Also, in order to get the review finished and online quickly (Qkore debuted at the Munich High End show in May), I decided not to muddy the waters by using Qkore with power products from other makers, although Nordost is unequivocal in recommending this.

Regarding my sonic impressions of Qkore, it's important to keep in mind that it addresses ground noise specifically; the hot and neutral are not affected and they are exactly what Shunyata Research does address with its Denali products. So while Denali and Qkore are mutually exclusive, they are also able to work together toward a greater sonic whole. -Marc Mickelson

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July 1, 2017


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Bob Watson

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