April 2002

Manley Labs
Steelhead Phono Pre-Amplifier

Review By Steven R. Rochlin
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  In this age of "high-resolution" digital formats, it may seem strange for new turntables, tonearms, cartridges and phono stages to be introduced into the marketplace. With vinyl, we have this over half-century old technology of a diamond scraping over a plastic polymer to reproduce music. Worse still, when cutting a master vinyl stamper one has  to employ some major frequency response alterations since the vinyl production system can not allow for a flat frequency response on the record. Therefore engineers have to equalize the signal that is cut into the grooves while a phono stage reverses this equalization. And here we all felt that most audiophiles were against equalization, yet we all can not deny many love music on vinyl.

What about all the new blue-ray laser system and other advances in digital technology? After all, this is the modern age of the Internet where e-mails cross the world digitally in a matter of seconds. Well let me tell you, i for one am still not convinced of "perfect sound forever" nor ready to sell off my prized and rare collection of music on vinyl. Fact is we have a professional audio company called Manley Laboratories who have won many awards for their achievements, yet have recently released their Steelhead all-singing, all-dancing MM/MC phono stage. Why would a company so keen in dealing with professional recording engineers and audiophiles want to take the time to spend their hard earned cash to design and construct a lowly phono stage? Maybe the reason is that many others, like myself, find music on vinyl highly enjoyable and therefore the good folks at Manley feel the need to put their best efforts to constructing their finest phono stage to date.

"I'm creeping back to life
My nervous system all awry
I'm wearing the inside out"
- Pink Floyd Division Bell

As with all Manley Labs audiophile products, you simply know it will have vacuum tubes. Per channel, there is one dual-triode 6922 used for gain and one 7044 employed for each output buffer. There are two white follower output buffers. After the first one you can escape to go to your pre-amplifier. Next in the signal path if you have not done this, there is a Noble volume control followed by the second white follower using the second 7044 dual triode. The Manley Steelhead is not just a phono stage, it is also a pre-amplifier. A hybrid cascode gain delivers wide frequency response and high-gain, yet with very low noise and low distortion. Negative feedback is used, though in minimal amounts. To quote the owners manual "The multiplicative aspect of the cascoded device's output (anode) impedance means that the most important characteristics of each gain stage are preserved even though the local negative feedback present in each block is very small. This approach makes the amplification factor of each stage insensitive to tube gain or transconductance variations which occur due to device production tolerance allowances or aging."

With this design, an extremely wide-band frequency response with precise adherence to the RIAA equalization curve is achieved.. Furthermore, this phono stage offers a plethora of adjustments. MM and MC cartridges can have various capacitance, impedance and gain needs. Therefore if a manufacture wanted to make a reference-grade phono stage, it would need to be adjustable. While i have had the honor of owning a top-end all silver wired step-up transformer (Audio Note AN-S6c), i know that having the ability for customizing the phono stage is very beneficial. True moving coil input impedance matching on the Manley Steelhead is adjustable, via a multi-tap autoformer, with 25, 50, 100, 200 and 400 ohms settings. For moving magnet the adjustments are made by resistive loading settings of 25, 50, 100, 200 and 47,000 ohms. Allowing for input capacitance adjustability, various controls allow for 10pF steps from 10pF to 1100pF. Due to a cartridge's need for various amounts of gain, this too is adjustable from 50dB to 65dB in 5dB steps. All these adjustments are front panel switchable using the various knobs provided and clearly marked. 

As for the main signal outputs, there is a conventional fixed output to feed a separate pre-amplifier, plus there is a second variable level output with a volume control to drive power amplifiers directly for those who crave signal purity. Both outputs are buffered by the supremely low output impedance 7044 white follower circuits which means they can drive fairly long cables with plenty of juice.

Looking inside, this unit is chock-full of expensive parts. There are four large MIT MultiCap capacitors, two huge autoformers manufactured by Manley at their factory, four 7044's and two 6922 vacuum tubes. Switching is made by rotary Grayhills and push-button EAO's. There are also quite a few IDC ribbon cables used only for logic control and relay switching while all audio is meticulously hand wired with a certain Synergistic cable, chosen for its extremely low capacitance. Virtually everything is kept in a mirror image for dual mono-type construction. The hefty outboard power supply has an umbilical cord that attaches to the rear of the Steelhead main chassis. This is to keep as much of the power supply noise from interfering with the critical analog stage. The front panel push buttons on the right and lights to the left are blue in color. The buttons include overall mute, sum (mono), DIM (reduces level by 20dB) and standby. As with many Manley Labs designs, their front badge lights up to give the overall unit a classic look. Lastly, the unit that was sent here for review had the gold faceplate which is now available by special order only. Manley has since switched back to their classic "Manley Blue" color which can be seen below.

"The grass was greener
The light was brighter
When friends surrounded
The nights of wonder"
- Pink Floyd Division Bell

Setup of the Steelhead was a snap and it only took a few records to find the desired settings after the usual 100 hours of break in. In fact some might say that due to the ease and highly adjustable load impedance/capacitance, the Steelhead is many phono stages in one. With my prized Clearaudio Insider Reference (wood body) and Audio Note AN-Vx cables i settled on 100Kohm load impedance and 30pf of capacitance with 55dB of overall gain. For some recordings there were slight adjustments made. Although the above settings were where I centered my adjustments, from there I could freely adjust to taste depending on the recording. After playing with the Steelhead and debugging a rare yet pesky ground loop in my system, my listening session began.

First let me state that the Steelhead has a built-in volume control and therefore many vinyl lovers can eliminate their pre-amplifier. This is highly recommended as, depending on the quality of your pre-amplifier, the gains can be anywhere from trivial to enormous. Within my system, the cj Premiere 17LS really showed how transparent it is! There was a very small, yet perceptible change that appeared to be a slight narrowing of front soundscape width and a very small amount of depth narrowing as compared to no pre-amplifier in the signal's path. Bravo conrad-johnson as the differences were so subtle it took me some time to realize them! Regardless, less = more so the cj pre-amplifier was taken out of the system. Furthermore, all digital gear was shut down when enjoying vinyl (as usual really). Using the Steelhead alone meant there were no other source components input wiring hooked into the unit. This is as pure as it gets folks.

Of course my trusty dedicated power and professional-grade Furman IT-1220 balanced power unit was feeding pristine electricity throughout the system. The amplifier of choice were my beloved Wavelength Audio Cardinal monoblocks while loudspeaker duties were performed by my reference Avantgarde Acoustic Duo 2.0. My VOYD turntable tonearm uses an Audio Note top-of-the-line tonearm with Audio Note all silver AN-Vx cable. The tonearm cable went directly into the Manley Labs Steelhead while interconnects out of the phono stage were the excellent BeterCables.com Silver Serpent and all silver Kimber Kable Select KS1030. Loudspeaker cable was the incredible Nirvana S-L and custom Nirvana Avantgarde jumpers. Power cord for the Steelhead and Wavelength Audio Cardinal monoblocks were from Nirvana as well.

While these highly sensitive loudspeakers seem to tell you everything, they also can be problematic on front-end gear that is less than dead quiet. The Steelhead is very quiet, yet there is a tad bit of noise (hiss). Nothing that really got in the way of the music. Besides, most audiophiles do not use 103dB sensitive loudspeakers and therefore no noise at all would be heard. This is simply a fact of life when using incredibly high sensitivity loudspeakers and not something that caused me to worry.

"Should I sing until I can't sing any more
Play these strings until my fingers are raw
You're so hard to please
What do you want from me"
- Pink Floyd Division Bell

After lengthy listening sessions what amazed me the most was the sheer speed and inner resolution of the unit. Due to this fact i decided that some fast-paced techno would really test the Steelhead. Prodigy Fat Of The Land went on the table. Now before all you "audiophile only music" folks stop reading, please understand that when reviewing i use music as a tool at times and not necessarily for enjoyment. After all, my job is to tell you the good, the bad, and the ugly. Of course a system is only as good as its weakest link and here is where having top notch gear is a must. The Steelhead allowed me to hear more within the Prodigy album than any other phono stage. It was easily able to unravel the (almost literal) kaos within the grooves of this record.

Moving on to harmonics and top to bottom frequency response, my favorite Miles Davis Cookin' from the Analog Production The great Prestige Years came into service [APJ 035]. Here the Steelhead not only once again portrayed immense inner resolution capability, it also was able to seamlessly track much of the dynamics. In fact it was incredibly analog-like as heard on master tapes. Oh how i love vinyl! The only small deviation was a slight lack of midbass definition. This would probably have gone unnoticed until i reviewed the $30,000 the Silbatone C-102 pre-amplifier with MM/MC phono stage (see review here). As some of you may recall from my Silbatone review, that unit set a landmark record for lower frequency response definition that far outpaced any other unit my ears have heard. My feelings are that the Steelhead is just slightly behind the Final Labs Music 4 phono stage for bass definition and on par with the remaining frequency response (review here and revisited here).

Speaking of the Final Labs Music 4, the Steelhead does have more resolution, but only by a small margin. Of course the advantages of the Manley Labs Steelhead ($7,300) over the Final Labs Music 4 ($3,700 plus $450 for the UM2 battery box) is tubes. The Final Labs is a closed system while the Steelhead allows tube aficionados to have fun with many 6922/6DJ8 variants. Of course the Steelhead's selectable impedance and capacitance is nothing to simply write off either. Still, they were both very close all in all. From trumpet to acoustic bass and drums, the Steelhead easily brought a smile to my face and a tap to my toes. There was a nice dose of wooden body to the acoustic bass while the drums' heads and shell sound was plainly evident. Of course this recoding features the genius of Miles' trumpet playing. As reproduced here, it was evident how his trumpet technique is, to this day, unequalled. His "signature sound" is only part of the outstanding ability behind the musician.

As for soundscaping and imaging, on the Miles Davis recording and the many others played within my system, i found that studio tricks of fake hall effects were plainly evident. There is a way natural acoustic music breaths within a concert hall. The sound, as expected, makes it way to the sides, rear as it washes over the audience. Of course some halls are better than others. This is where great resolution combined with the ability to track both macro and micro dynamics is key. Still, there seems to be some other factors at play. Read on...

Instead of singling out only one or two recordings to demonstrate the Steelhead's soundscape abilities, here is an overall impression. Front width between the loudspeakers is very good. Clean, precise, yet without any hint of etching or constraint. Alas, that is about all it seems to do. i virtually never heard the audiophile trick where music appears wider than the actual loudspeakers. Depth, while good, seemed a touch shortened. Overall, it was much less than the $30,000 C-102 pre-amplifier with MM/MC phono stage (see review here) and decisively placed the Final Labs Music 4 phono stage (review here and revisited here) as an in-between. While i was hoping for more, the Steelhead also seemed to slightly reduce brining hall sounds into the room (to the sides, into the room, and behind the listener). Of course i tried moving my loudspeakers a bit to accommodate the Steelhead, yet it seemed that my usual positioning was the best for overall enjoyment. Gains in one positioning would cause new problems in other areas. All in all this is my harshest criticism for the Steelhead. Perhaps changing the 6922 for a Bugle Boy 6DJ8 would have won the day here? As i said earlier within this review, tube amplifiers allow one to easily experiment more than with solid-state devices.

"Encumbered forever by desire and ambition
There's a hunger still unsatisfied
Our weary eyes still stray to the horizon
Though down this road we've been so many times"
- Pink Floyd Division Bell

All in all the Manley Laboratories Steelhead offers both MM and two MC inputs, a fixed and variable output with an amazing array of flexibility with both resistance and capacitance load selection. Die hard vinyl lovers will probably eliminate their current pre-amplifier in favor of the excellent variable output section within the Steelhead. With the incredible ability of speed, timing and effortlessness at unraveling all the music within, the Steelhead may bring newfound discoveries contained in those vinyl grooves. The only major drawback i could detect is the lack of full 360 degree soundscape ability. This lead to the feeling of listening to a bubble of music versus sitting within the actual event. Perhaps a tube swap would be the solution?

The other interesting situation is that the recently reviewed Final Labs Music 4 phono stage comes very close to that of the Steelhead, yet at a saving of over $3,000. Of course the Steelhead provides MM and MC while the Final Labs is generally for MC only. Furthermore, the Steelhead has more speed than the Music 4 and also infinitely more adjustments as well. Is this worth almost double the costs of the Music 4? In the end it is up to you to decide. Those who prefer tubes and do not like solid-state or having to fool around with the Final Labs 24-battery ("C" size) power supply and costs involved, the Steelhead may be the winner. Add to this the ease of diversity in changing both resistance and capacitance to "flavor" the sound to better reproduce each individual recoding and the Steelhead comes out a winner. For those who have cartridge fetishes and change many times a year, the Steelhead is a must in my humble opinion. Of course in the end what really matters is that you...

Enjoy the Music,

Steven R. Rochlin

Specifications

Vacuum Tube Compliment: two 6922 (gain) and four 7044 as output buffers

Fuse Type And Ratings:
   117 VAC: 1.5 Amp 3AG slow-blow main
                 0.5 Amp 3AG slow-blow logic

   234 VAC: 0.75 Amp 3AG slow-blow main
                 0.25 Amp 3AG slow-blow logic

Moving Magnet Input Impedance: 5-step user adjustable via fixed low-noise resistors - 25, 50, 100, 200 and 47,000 ohms.

Moving Coil Input Impedance: 5-step user adjustable via multi-tap autoformer - 25, 50, 100, 200 and 400 ohms.

Input Termination Capacitance: Variable in 10pF steps from 10pF to 1100pF.
(1.1nF). Residual input capacitance less than 40 pF.

Gain Steps: four-step user adjustable, 50dB, 55dB, 60dB and 65dB active gain at 1kHz referred to FIXED
Output jack, 10k-ohm load. Additional gain available via MC step-up autoformer.

Deviation From RIAA Curve: Less than +0.5dB / -0.3dB from 20Hz to 20kHz, any gain setting.
Typically less than +/- 1 dB from 10Hz to100kHz

Inter-channel Differential Phase: Less than four degrees from 20Hz to 20kHz, any gain setting.
Typically less than two degrees.

Inter-Channel Differential Gain: Less than +/- 0.5dB from 20Hz to 20kHz, any gain setting.

Dynamic Range: 101dB @ 1kHz, 1% THD

Maximum Output: +27dBm @ 1KHz with 3% THD into 100Kohm load

FIXed Output impedance: 150 ohms. Minimum suggested load greater than 1500 ohms.

VARIable Output impedance: 75 ohms. Minimum suggested load greater than 600 ohms.

MM Noise:
     50dB gain = 86dB s/n
     55dB gain = 84dB s/n
     60dB gainb = 80dB s/n
     65dB gain = 75dB s/n

MC Noise: 
     50dB gain = 84dB s/n
     55dB gain = 80dB s/n
     60dB gainb = 75dB s/n
     65dB gain = 70dB s/n

Unit Weight:
     Steelhead: 15 lbs.
     PSU: 18 lbs.

Chassis Dimensions:
     Steelhead: 19" x 3.5" x 15.5 (WxHxD)
     Power Supply: 13.5" x 4.5" x 11.375" (WxHxD)

Price: $7,300

Company Information

Manley Laboratories, Inc.
13880 Magnolia Avenue
Chino, CA 91710

Voice: (909) 627 - 4256
Fax: (909) 628 - 2482
Website: www.manleylabs.com