The Steelhead ver. 2 phono preamplifier from Manley (reviewed HERE) is considered by many a reference design. The ‘reference’ here refers both to the quality and to being the reference point. Ms. Manley, head of the company, together with her engineers succeeded to make the product widely accepted by other manufacturers of phono preamps, turntables and cartridges, as well as by the mastering studios. Audio magazines’ editors are also often ‘blessed’ with it, to name just the analog ‘guru’, Michael Fremer (my interview with Michael HERE). Nobody claims it is the best device in the world as some will point to its input transformer being a weak point; others won’t like its tube amplification stage, etc.. However, it doesn’t change the fact that it is a reference point for each sensible manufacturer, one that must be either aspired to or to disputed, but cannot be pretended not to exist.
How did the Steelhead earn such esteem? Definitely with its sound quality. Yet it is not only a great sounding device but also one very comfortable to use, with knobs on the front panel, an optional volume control, an analog input, etc. Its major advantage also lies in a certain “consistency” of its sound – it neither enchants us nor exaggerates, trying not to remove anything. Regardless of the record it behaves exactly the same. Its disadvantage is the high cost.

The Chinook phono preamp is the latest offering from Manley Labs. According to the manufacturer, it can be described as the Steelhead’s younger brother, as it sports many design concepts straight from the top preamp, including identical output stage. The advantage of the Chinook, however, is that it is much less expensive. In Poland it costs 9,500 PLN; the Steelhead is a steep 23,900 PLN.
Like the Steelhead, the Chinook uses both sections of the two 6922 tubes in each channel for signal amplification. The RIAA equalization is performed in passive circuits to maintain the ± 0.5 dB accuracy within 20 Hz-20 kHz range. The signal is then fed to another 6922 dual triode working in the White-cathode-follower (WCF) output stage. The WCF design has been chosen due to its low output impedance and high output current, allowing the use of long cables and driving low impedance loads.
The Chinook can be adapted to a particular cartridge. The change from the MM to MC is somewhat awkward – we need to remove the cover and get inside in order to access it. We set gain to 45 dB for MM cartridges and 60 dB for MC cartridges. Other adjustments - impedance and capacity – are found on the back panel in the form of typical micro-DIPs. There are 31 available settings covering the impedance range of 26 Ω - 800 Ω and a separate 47 kΩ setting for the HO MM or MC cartridges. Capacity can be set in the range of 50 pF - 350 pF (in seven steps). It needs to be added that the Chinook’s enclosure is very similar to that of the Steelhead, with a thick steel-blue anodized aluminum front panel featuring rack-mount ears on both sides. Evidently, Manley’s roots are in the recording studio. The Chinook is a tube preamp with a built in solid state power supply, unlike the Steelhead that sports an external PSU in a separate enclosure.

SOUND

Given Steelhead’s price level it would be foolish to expect a similar level of performance from a component costing much less than half of the reference design. Experience shows that good gear is expensive. If something costs less than the best, we can expect some cuts to keep the cost down. The trick is to make the inevitable sonic changes disproportional to these cuts. Hence I was not surprised to learn that the new Manley preamp sounds to a large extent different from their top model. Although I did not have the Steelhead for a direct one to one comparison, I had instead my reference point that I’d also used while reviewing the Steelhead – the RCM Audio Sensor Prelude IC preamplifier. And remembering (with a little help from my review) how the Steelhead had fared against the Sensor Prelude IC I was able to compare that with how the latter stacked up against the Chinook.
The comparison clearly shows that Ms. Manley has managed to maintain in her new product a kind of ‘maturity’ of sound, its saturation. That’s fairly typical for this manufacturer – sonics shaped by large virtual sources, by a kind of palpability of sound. It is not a far away, distanced presentation. Nor is it not too much forward sounding since its somewhat relaxed dynamics does not allow for that; however we are not talking here about falling asleep but about bringing musical events closer to the listener.
If we were to look for the cause of that I think we would find it in midrange saturation combined with a slight rounding of the highs and lows. It is quite evident, especially when we compare that sound to the solid state Sensor, but also to the rather warm Vitus Audio SP-102 preamp. Even the ultra-smooth Array Audio Obsidian PH-2 which I reviewed for “Audio” magazine seemed to have had a wider bandwidth.
Despite that it is not that the Manley only ‘sings in midrange’ that we PERCEIVE the sound as limited. On the contrary, what you can hear is that it provides a slight but nevertheless present boost around 2 kHz which results in its ‘breath’, and subjectively improves dynamics ‘opening up’ the sound. It adds some flair and masks the slightly withdrawn sonic band extremes.

How does that translate into concrete records? I was curious myself to see how the U.S. preamp treats various recordings, such as Jane-Michel Jarre’s Zoolook, This is Tommy Dorsey pressed on the Dynaflex vinyl, clearly a Satan’s invention, or some sophisticated material from Selections from Bill Evans Live at Top of the Gate. These LPs and generally all I listened to on the Manley sounded really, really cool! That is a firm, vibrant sound with zest.

It was particularly interesting with rock albums. Deep Purple’s Perfect Strangers on a Japanese pressing put to deep shame even the best digital versions I know. There was ample dynamics, bass, and the ‘groove’. CDs with that material sound flat and muffled. The Chinook showed that the album may not be the best in terms of music production and it’s the dynamic that’s the limiting factor but at the same time it also pulled out that something ‘extra’; something that makes albums more ‘listenable’ and that gets us in the gut. I mentioned the Tommy Dorsey’s album. This edition of his hits from 1935-44, including Frank Sinatra on vocals, had been pressed on an ‘contraption’ called Dynaflex. The idea behind it seemed to be right. Introduced in 1969, the RCA Records patent was meant to reduce travel noise, help the record lie flat on the platter, and – as a side effect – permit more records to fit in record changers. The records were made of a special variety of pure vinyl (back in those years most records had been pressed on vinyl ‘recovered’ from old records) and were extremely thin. They bend when we hold them. Today, when standard for records is 180 g, and the best weigh in 200 or even 210 g, the 80 g record (I weighed it!) must seem like a joke. Concerning their sound quality there are mixed opinions. I am inclined to agree with those who believe that a mint Dynaflex record (and I bought the Dorsey still wrapped in foil) can sound really good. Travel noise is low in the midrange increasing in the high end. There is no low bass yet it is not cut off but rather withdrawn (that’s a major difference). The overall sound quality, the “what you can hear” is really good though.
The reason I write all this is to show that the Manley can differentiate recordings quite well. At first glance it seems that the preamp prefers large imaging, big sound and leaves no room for spectacular resolution. There is some truth to it for it is not a particularly detailed sound, with deep instruments bodies, etc. Despite that, with each next record we know exactly what we’re listening to; we feel what we are dealing with. Including the Dynaflex. The Chinook showed both its advantages and disadvantages without obscuring the music. These are really old recordings, especially on the A side, yet they had their own character with the reviewed preamplifier. They were covered with the patina of time, there’s no way around it, but it was on equal terms with the music, with the “truth of the screen.”

As I said, rock music sounded really well on the preamplifier. But in the end, when I was listening just for fun, mostly through headphones, deep in the night, I usually reached for albums Dorsey or Nat “King” Cole, Evans, and Chet Baker. For although this sound’s advantages are best heard on a stronger material, including electronic music, since there is no harshness or brightening as the Chinook rounds the attack, slightly warming the sound, it also the shows vocals a bit closer to us, presenting them in a close, intimate way. Since the virtual sources are large, it is the voices of the “golden age” of jazz that seem to take the best advantage of that. Despite the fact that this is not the most resolving sound, not even the most dynamic.
The Manley people however went after something else in my opinion – they didn’t try to roll out a copy of the Steelhead. Neutrality at any price, which would need to be high at the lower price level, is a dead end, leading to dry and lean sound. It seems that the Chinook is the phono equivalent of another new preamp from this manufacturer – the linear Jumbo Shrimp. This is a very similar sound, i.e. exhibiting similar aesthetics. Rather warm, not too pushy, very intimate but still with oomph. Manley somehow succeeded in this coincidence of opposites. What am I saying, not just ‘somehow’! There are no coincidences with companies of this class; instead there is a pursuit of established goals no matter how much time needs to be devoted to it. No wonder then that designing a less expensive and yet so successful version of the Steelhead took the American producer so much time. For while it seems very difficult to design a top notch product regardless the cost, how much harder it is to scale it down, reduce manufacturing costs and the end price, still maintaining all the important features of the more expensive original.
The Chinook is not a 1:1 transfer of Steelhead’s sonics down below the 10,000 PLN pricing region. But we also know that it is the same team behind both products and that they share some general sound characteristics. Very, very good product that's not only great sonically but incredibly quiet at the same time – not a trace of hum!

DESIGN

The Chinook is a MM/MC phone tube preamplifier with a solid state power supply. Its look is characteristic for the American manufacturer – a thick aluminum front panel in characteristic color with an illuminated window sporting the company and model logo. Below the window there is a blue-lit mechanical switch. There are rack-mount ears on both sides of the front panel with milled holes for rack mounting.
Preamp gain can be set to either 45 dB or 60 dB; input impedance and capacitance can also be adjusted. The gain switch is located inside the enclosure while the impedance and capacitance mini-DIP switches can be accessed on the back panel. There is a detailed description of the available settings at the back. We have very many steps - 32 for impedance and 7 for capacity adjustment. On one side of the switches area there is a widely spaced pair of stereo input sockets and output sockets on the other side. The sockets with Teflon dielectric are manufactured by Manley. Actually, most components are manufactured in house at the company’s own factory in California. The back panel also sports an EIC socket.

Amplification circuit is based on vacuum tubes – the input stage is built on two 6922 Electro-Harmonix dual-triodes per channel (replacement: 6DJ8, 7308, ECC88); another 6922 dual triode works in the White-cathode-follower (WCF) output stage; these are NOS tubes from JAN (Joint Army Navy) military surplus. In order to prolong their life, they are equipped with an automatic timer. Switching on the Chinook by pushing the front panel button leaves the output muted while anode voltage is gradually raised. After 45 seconds the relay clicks in and the device is ready to work. Manley declares the deviation from the RIAA curve to be less than ± 0.5 dB in the 20 Hz-20 kHz range (typically less than ± 1 dB between 10 Hz and 100 kHz).
The whole electrical circuit is mounted on two printed circuit boards, separated by a metal screen - one is the power supply board, and the other is the amplification circuit. Power supply is based on a large, flat toroid transformer. Both filament and anode voltages are rectified and stabilized. Additional filtering of the anode voltage is based on components placed right next to the tubes. The output stage features very large, polypropylene coupling capacitors – MIT MultiCap. All electrolytic capacitors in the power supply bear the Manley logo, but they are known to be manufactured by Cornell-Dublier. The input and output are connected to their respective sockets via cables manufactured by Manley, shielded with aluminum foil.