And RADIA Power Amplifier
The Dynamic Duo!
Review By Alvin Gold
here to e-mail reviewer.
Hovland is... Start again, Hovland was just a name as far as I was concerned as recently as a few months ago, buy I have an excuse as the brand has had a very low profile in the UK so far. I have since learned, and pass on to these in equal ignorance, that Hovland is a
small yet long standing brand that makes just four meticulously designed hi-fi
components. Each is very much in specialist audiophile territory, two of which are power amplifiers, and two pre-amplifiers. A fifth component, a remote control tube pre-amplifier, the HP-200, is currently beginning to roll of the production line.
Hovland also makes and distributes a range of high grade components, namely cables which carry Hovland branding, a mains
line conditioner, and their best known product range, audio grade film and foil capacitors which sell under the MusiCap brand, which are sold to some 250 manufacturers world wide, as well as through the retail channel.
It is with these components that the Hovland story starts. Hovland was founded by Bob Hovland (CEO) and previously worked for Marantz when the company was based in Sun Valley, California. Naturally this was before the Japanese takeover in the early
1970's. Hovland was formed along with Michael Gargas, Jeffrey Tonkin and Alex J. Crespi, responsible respectively for production, industrial design and sales & marketing, and established itself with the passive components and by undertaking upgrades of classic hi-fi components from various brands, only later developing complete amplification products using solid state and tube based circuit topologies.
Let's lay it on the table, because I don't want this to get in the way of the review. I don't like tube amplifiers. Correction I don't usually like them very much. Rightly or wrongly, I associate most valve amplifiers with a sweet gentility that detracts from the bleeding edge, the naked sense of music happening that defines truly compelling music making. Tube amplifiers often don't drive real life loudspeakers very effectively, especially if they are a tad reactive or current hungry, and they often have a limited subjective bandwidth and dynamic range. But I accept there are rare exceptions, and this appears to be one of them.
In fact the power amplifier is fully solid state. It is only the pre-amplifier that uses tubes, and then in a sort of hybrid configuration in which the power supply section is solid-state, a decision based on the need to ensure stable, drift free operation in the long term.
The interesting point here is not whether this ultimately represents a compromise. All circuit configurations are necessarily compromised. The interesting point to me is the holistic nature of the two Hovland designs, which were meticulously developed over very long timescales, and which use whatever technology suggested itself at the time as being best fitted for the job in hand, in this case irrespective of whether it used tubes or transistors. As Alex Crespi explained ain conversation, with the right design choices and circuit techniques, neither technology should be distinguishable from the way they sound at the speaker output. He also pointed out that Hovland's interest in solid state predated their interest in valves, and that most of what people like about valves are nothing more than
colorations. Similarly the common complaints make about solid state: the hard, steely edge, the granularity, are mostly nothing more nor less than the end result of poor design. I don't have the design expertise to judge one way or another, but this thinking certainly reflects my own everyday experience.
And so to the nitty gritty. The HP-100 is a line level pre-amplifier, essentially a straight line level device with a limited number of user features, though a phono version is available. Essentially a tube based design but with a solid-state power supply as indicated above, the HP-100 is available in two versions, and with one additional option. The two main versions are line only, and line plus phono, the tube based phono stage with a 0.07V sensitivity at 1kHz being best suited for moving magnet cartridges or high output MCs. The option is an external transformer for use with low output moving coils. This unit has 1mV sensitivity and a load impedance of 530 Ohms, with provision available to reduced impedance loading if required. Only the line version was tested here.
The pre-amplifier offers eight inputs selectable by a large front panel rotary control, plus a tape monitor option, which increases the input count to a generous total of nine. Stereo/mono switching, a stepped balance control with 1dB steps over a + or - 5dB range and mute switching are available. The volume control, which in many ways is the heart of the design, is a 31 position silver contact precision stepped attenuator with 2dB resolution (full mute is available at the lowest setting, leaving 30 active steps). The tube complement includes two 12AX7s and one 12AT7 sourced from Sovtek.
Onwards and upwards. The RADIA power amplifier is a fully solid state dual mono design that has a J-FET input stage which providers a high (50k Ohms) input impedance that allows it to be driven by long interconnects with negligible effect on the audio signal. The output stage is
bipolar, and uses T-03 metal can devices in a fully complementary output. Unusually the mains transformer is a frame type, and not the torroid you might have expected, but the choice was made on purely sonic grounds according to Hovland. Power output is rated at 125 Watts per channel into 8 Ohms, and 200 Watts in 4 Ohms, both channels driven. Socketry is limited to a pair of phono input socket and a pair of 4mm binding posts per channel. Both power amplifier and pre-amplifier are non-inverting.
Although hardly central to the theme of a high end pre/power amplifier combination, the build and presentation of the two components is striking to put it at its mildest, its details indicative of a culture of meticulous attention to detail. Both units made extensive use of thick acrylic panels that are bolted to a relatively skeletal space frame that is designed to reduce electromagnetic coupling to the active circuits, but extensive screening between circuit blacks is included. The pre and power amplifiers are usually heavy at 27 lbs. and 73 lbs. respectively. The acrylic panels helps maintain structural integrity, the result of which is that the pre-amplifier is unusually free from the insidious effects of acoustic feedback, which is often a factor with tube based designs. Another design priority is thermal tracking, especially of the power amplifier output stage which is addressed by appropriate design of the airflow over that section of the circuit, and by careful design of the biasing state. Both units make extensive use of Hovland internal Generation 3 cabling and MusiCap capacitors, though not exclusively
-- DNM slit foils are used in the pre-amplifier for example -- and the acrylic sections has been exploited with discreet internal lighting (which can be controlled with rear panel switches) to bathe the front panel with a distinctive blue glow.
First impressions were that the Hovland combination is unprepossessing but competent. But as all know, first impressions can be deceptive. In this case the rather bland headline conceals a much more subtle and complex picture, and incidentally a much more satisfying final result.
The two components landed on me while I was busy with a variety of quite exotic loudspeakers and source components. The main loudspeaker for most of the test period was the Focal.JMlab Alto, which I wrote about recently, but there were others too from Lumley (primarily a UK brand) and from B&W (the 800). Source components - well take your pick. There was a valve CD from Balanced Audio
Technology 9BAT), a Mark Levinson 390S CD player (RIP) and a Krell SACD
Standard, Oh and a Sony XA9000ES, which is another SACD/CD player, which like the Krell is the genuine article, that is no DVD.
There were few real practical issues, though the pre-amplifier is not the quietest I have encountered. Correction, it can be a little hum and noise prone in some combinations, in particular when used with the BAT player. I never did fully establish quite where the blame lay, but I suspect an earth loop problem of some kind. Certainly the combination was extraordinarily responsive to the mains routing, and I found I was able to affect a cure simply by taking the pre-amplifier back to a different mains socket, even though the new socket was on the same mains supply ring.
Bizarre! This may be some peculiarity of the British mains supply, or the transformer used for the European version of the Hovland, but when it was properly sorted, hum and noise were only slightly above what I would expect of a good solid state combination, and in any case only audible when using the Alto with the ear within a few inches of the speaker baffle.
Warming up the pre-amplifier is a rapid process, which is just a well with any tube based amplifier. The RADIA power amplifier, which was not new when I received it, took rather longer to come on song, perhaps three or four days before I felt I was getting the best from it. Perhaps it's just a well then that the amplifier runs relatively cool.
Although it would be possible to discuss the sound of the two components separately, it is difficult to split them in this way. There is little to choose between them on voicing ground. The pre-amplifier doesn't sound like a tube pre-amplifier, and the power amplifier doesn't sound solid state. In fact they are quite similar in important ways. They have what is best described as a liquid quality when presented with musical material. Soundstage depth can go back seemingly almost to infinity - in fact the perception of distances and depth generally was always a little greater than expected, but more to the point, the differentiation of depth imagery was beautifully
realized. In a well recorded full orchestral recording ( Boulez Mahler Song
Of The Earth on DGG SACD) yet ordinary commercial release, not an audiophile special, every section of the orchestra and the positions of the vocalists could be pinpointed with complete precision in both planes so that the perception of a soundstage with a near physical reality was extraordinarily cogent. This was with the disc played from SACD in stereo, not
multi-channel (obviously), and although the Alto was clearly contributory, much the same quality could be heard through other speakers such as the B&Ws. There are plenty of amplifiers which can pull off a similar trick, but very few of them are also able to deliver explicit, direct sound forward of the plane of the speakers when required. But the Holland could manage this trick too, and with ease.
Important as imagery is in its own right, I sometimes feel it acts at least in part as a litmus test for overall system performance. If there is anything wrong with a system, it will somehow be reflected in the way that stereo is presented. But here the other things worked just as well. The liquid quality of the Hovland is a case in point. This is a naturally expressive amplifier, one that can be utterly refined when called for, and which can present detail with enough precision to make the hair stand on end, but there is no loss of energy at either frequency extreme, and a welcome absence of hardness or grain. The balance is lively, but not too lively, refined without being plush or lacking definition, and the bass is powerful and well integrated. Perhaps not Krell standard for power and the ability to play tunes with complex material, but not far short qualitatively at least.
The other very important attribute that the Hovland pair bought to the party, and this is clearly a power amplifier quality, is the ability to take control of the loudspeaker in a way that makes it sound at ease with its
role... not governed by the loudspeakers' idiosyncrasies. At least that was clearly the case with the loudspeakers that were available during this
test. Although they do not cover all eventualities, I have come to recognize
that the B&W is quite a punishing load.
Unique in their physical presentation, this is a medium power combination that is the epitome of the high end with its concentration on the engineering essentials in the service of good music
making. It also gives confidence in its ability to deliver over the long term.
Separately or in combination, the HP-100 and the RADIA are effortlessly natural and organic, exquisitely musical and always consistent in their
behavior. This includes during both low land and high volume levels alike. In this context their pricing is very realistic.
Type: Tube stereo line level pre-amplifier
Frequency Response: 10Hz to 25kHz (+0/-0.25dB)
Input Impedance: 50k Ohms
Signal To Noise Ratio: 80dB ref 3V (A weighted)
THD: <0.1% at 3V out
Inputs: 8 at line level plus tape monitor loop
Dimensions: 18.25 x 17.38 x 5.25 (WxDxH in inches)
Weight: 27 lbs.
Warranty: Three years parts and labor (90 days on tubes)
Type: Solid-state stereo power amplifier
Power Output Per Channel:
125 Watts at 8 Ohms
200 Watts at 4 Ohms
Input Impedance: 50k Ohms unbalanced
Voltage Gain: 26dB non-inverting
Frequency Response: 5Hz to 20kHz (+0/-0.25dB)
THD (At Rated Power):
8 Ohms <0.1% 1kHz
4 Ohms <0.15% 1kHz
Signal To Noise: 92dB ref 120 Watts, 8 Ohms (A weighted)
Dimensions: 18.25 x 16.65 x 7.2 (WxDxH in inches)
Weight: 74 lbs.
Warranty: Three years parts and labor
1545-A Pontius Avenue
Los Angeles, California 90025
Voice: (209) 966-4377
Fax: (209) 966-4632