Manley STEELHEAD RC User Manual
OWNER’S MANUAL
MANLEY
STEELHEAD RC
MM/MC GRAMOPHONE CARTRIDGE PREAMPLIFIER
CONTENTS
SECTION PAGE
INTRODUCTION 3
INSTALLATION PRECAUTIONS 4
FEATURES AND APPLICATIONS 5
OPERATIONAL NOTES 9
REMORA REMOTE CONTROL OPERATING INSTRUCTIONS 12
TROUBLESHOOTING 16
MAINS CONNECTIONS 18
SPECIFICATIONS 19
rev5/2/11cd
INTRODUCTION
THANK YOU!...
...for choosing The MANLEY STEELHEAD RC phono preamplier. Please read over this
manual carefully as it contains information essential to the proper operation and maximum enjoyment of this fabulous instrument.
The MANLEY STEELHEAD RC is designed to provide that rare combination of maximized
sonic performance coupled with a generous ability to adapt to any moving magnet, moving coil
or iron vane phono cartridge you may wish to use. With the STEELHEAD’s feature compliment,
you no longer have to settle for what a given cartridge sounds like with a xed predetermined
preamp load impedance, or wonder what that same cartridge might sound like when presented
with different loading arrangements. What best suits your particular phono cartridge, system, lis-
tening room and personal preference is now merely a ick of a switch away! The STEELHEAD
adapts to accommodate your situation, rather then the other way ‘round.
To this end you will notice that it is the anticipation of your preamplier needs which has
driven every detail of the STEELHEAD’s planning, engineering, styling, operating convenience
and adaptability.
UNPACKING
Unpack the preamplier carefully and make sure that all supplied accessories are present.
Examine all items for any possibility of shipping damage. All six tubes should be standing at attention in their sockets. If the unit is damaged or fails to operate, notify the shipper or your dealer
or us or your local authorities immediately. Or if you suspect The Shipping People threw it off
the airplane and onto your front porch whilst ying overhead at 30,000 feet, notify the ship-ping
company without delay and complain to them as we only guarantee this unit to be able to survive
a drop of 23,487 feet or less.
Your STEELHEAD RC was packed with extreme love and care. Each box includes the following components and accessories:
a) 1 each, 6 foot IEC 3-conductor mains power cable (that you will probably replace with
an expensive audiophile cord anyway.)
b) 1 each, Owner’s Manual per pair (that we hope you will keep reading.)
c) 1 each, Outboard Power Supply Unit with captive grey power cable and big fat connector.
d) 1 each, REMORA Remote Control.
It is prudent to retain the shipping materials for future use, as they are custom-formed for
the preamplier and will greatly minimize the chance of shipping-related damage should you
ever need to put your precious Steelhead in the careless hands of The Shipping People again.
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INSTALLATION PRECAUTIONS
a) Avoid locating the preamp where it will be exposed to direct sunlight, excessive humidity, dust or moisture.
Extreme environments may temporarily or permanently degrade preamp performance.
b) Keep the preamp housing away from sources of strong magnetic eld radiation, such as large video display
CRTs, large power lines or power/audio transformers in nearby equipment. Extra measures have been taken to
shield the magnetically sensitive bits inside the preamp housing. Nevertheless these measures can be over-
whelmed by strong outside inuences. Keep in mind that the tiniest disturbance along with the desired signals
will be amplied many hundreds or thousands of times.
c) Locate the preamp away from heat-radiating sources, such as other large amps, political demagogues or
space-heating equipment.
d) Make sure the preamp and power supply is off before making any system connections. Do not remove or
insert the large 16-pin circular power supply connector when the power supply mains switch is in the on (|)
position. Do not hot plug the system.
e) Dissipate any static electric charge build-up on your body by touching the enclosure before making or chang-
ing any system connections. The preamp electronics are fairly robust as far as immunity to damage from static
charge is concerned, but total immunity cannot be had without unacceptable compromise of audio performance.
f) Be careful to feed only low-level phono cartridge signals to the preamp input connectors. Sustained line-level
signals above 15 volts peak may cause damage to sensitive MC input stages even when the preamp is in the
standby mode or when the power is off.
AC VOLTAGE SELECTION
The STEELHEAD system may be set to operate on either 117 or 234 volts A.C. by means of a rotary switch
located on the power supply P.C. board. The power supply’s mains-voltage selector switch is normally preset to the
mains voltage at the customer’s location prior to shipment. If, however, the preamp provenance is unknown then the
mains-voltage selector switch should be checked and reset to the correct voltage if necessary. The mains fuses must
also be checked for proper ratings and changed if necessary. Failure to correctly set the mains selector switch or use
properly rated fuses can cause extensive damage to the system which is of course not covered by the warranty. The
mains fuse may be checked by rst disconnecting the IEC mains cord from the power supply’s power inlet plug. Then
gently press the small leaf spring on the side of the rectangular gray fuse retainer cap. The fuse and cap should spring
outward toward your ngers. Inspect the fuse for the proper rating; change if necessary. Refer to the fuse-rating chart
in the specications section of this manual.
To inspect or adjust the mains-voltage selector switch it will be necessary to remove the top cover of the
power supply enclosure. For this you will need a #1 Philips screwdriver, and a 3/16 inch at blade driver to change
the selector switch setting.
Before opening make sure that the power supply is unplugged from mains power and the STEELHEAD
preamp. Once inside you will see tall cylindrical high voltage energy-storage capacitors, which can be a shock nuisance even when the supply is not energized. Therefore, if the supply has been recently power cycled, let the supply
capacitors discharge for 15 minutes prior to opening. Then remove 8 Philips 4x40 retaining screws from the cover,
followed by the cover. Locate the voltage selector switch near the mains power entry / fuse / power switch module.
The switch face is the black round object, about 1/2 inch in diameter, with white voltage numbers “110” and “220”
on the rotor and a white triangular selection indicator on the stator. Notice that the “110” and “220” markings on the
switch should not be interpreted as being the precise voltage needed to operate the preamp system. Using the 3/ 16
inch screwdriver rotate the switch, if necessary, so that the mains voltage you intend to feed the power supply lines up
under the selection indicator. Be sure to replace all screws when reassembling.
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FEATURES AND APPLICATIONS
1. HIGH PERFORMANCE FRONT END
The STEELHEAD RC preamplier makes the best use of active and passive component and circuit
developments generated over the past half-century. The hybrid cascode gain blocks simultaneously deliver
wide-band high-gain, low noise and low distortion performance without having to resort to heavy-handed
amounts of negative feedback. Or overly complex circuit topology. 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
amplication factor of each stage insensitive to tube gain or transconductance variations which occur due to
device production tolerance allowances or aging.
Other uncommon traits include high quiescent and operating current in each gain stage. This lowers
the static and dynamic impedances found within each stage and raises system bandwidth. Musical material
which would cause a cave-in of the typical current-starved 12AX7-based preamplier circuit are conveyed
uninchingly by these amplier stages.
2. ACCURATE “4-CORNER” RIAA EQUALIZATION
In the spirit of high delity, all four RIAA phono equalization corner frequencies or time constants
have been specically addressed in the STEELHEAD preamplier. Historically most designs have concentrated on the “big three” time constants of 3180, 318 and 75 microseconds. This ignores the fourth corner
of about 3.2 us, which when ignored causes most phono stages to continue rolling off the highest octave
signals coming from the phono pickup, rather than turning the nal “corner” and shelving to at response at
about 50 kHz. Careless removal of upper octave bandwidth causes the recovered audio to become somewhat
lifeless and remote, with needless loss of impact, detail and percussiveness. Ironically this signal content is
precisely what is omitted from all currently popular digital audio delivery formats, and is one of the chief
culprits behind the homogenous upper octave sonic characteristics of those formats.
As with all equalizing ampliers intended to correct a given form of frequency-selective emphasis
curve, care must be used when building the restorative compensation networks. Great care must be exercised
if the goal is to produce a highly accurate passive network coupled to low-feedback ampliers. And experience has shown that the effort spent in faithfully adhering to the inverse RIAA equalization curve produces
results that easily justify the additional procurement and manufacturing costs. To this end, only hand-selected and/or 1% tolerance components are used throughout the RIAA equalization network. Add to that the
factory-set variable capacitors, and the result is very high equalization accuracy where small component and
circuit layout variations that other manufacturers ignore are netted out. This yields impeccable inter-channel
phase and gain matching at any gain setting. In short, the STEELHEAD will magnify the differences in the
character and personality of your vinyl recording collection, cartridge, tonearm and turntable. A microscope
for the ear! Be prepared to hear previously undiscovered musical content as you play back your favorites!
5
3. SWITCH-SELECTABLE CARTRIDGE LOAD IMPEDANCE
An effective means of varying the load seen by the MC cartridge has been included in the form of
a 5-position rotary switch. This switch selects various taps on a specially manufactured dual-primary bi-
lar wound, high-bandwidth low-resistance and multiple-shielded nickel-core step-up autoformer. A drama
to make, the autoformer permits the minute MC cartridge signal power to be efciently and transparently
transformed from low-volts/high-current to high-volts/ low-current. By avoiding conventional parasitic
cartridge termination resistors, none of the MC cartridge’s tiny signal power is thrown away before am-
plication. This results in improved system signal-to-noise ratio. Quite worthwhile provided, as in the
STEELHEAD, the autoformer has the necessary performance for the job. This pivotal component has had
engineering attention lavished upon it in the only way possible or practical: The Manley Labs magnetics
department. In-house transformer prototyping and manufacturing capabilities permit realization of extraordinary transformer designs.
You may now audition your MC cartridge at or near the manufacturer’s specied loading resistance without sacricing any signal power through a parasitic load resistor. And explore the interesting
tonal shifts caused by intentional mild or severe mis-termination of the cartridge. The “right” setting will
ultimately depend on the cartridge in use, type of music being heard, other downstream equipment and,
most importantly, your personal preference. There will no doubt be moments when a technically “wrong”
setting will be musically “right” for a given situation. Do rest assured that, in this instance, a technically
wrong setting is completely harmless for all equipment involved.
In the case of the MM input, the typically higher cartridge output levels allow xed resistor termination, with clockwise-most switch setting being the standard 47k-ohm load resistance. Those MM cartridges
capable of properly driving low impedance loads between 25 and 400 ohms should be auditioned through
both the MM and MC inputs. By doing so you may nd the most appropriate sonic character through the
use of unconventional input arrangements. In short, experiment; don’t let the control labeling stop you. On
the contrary, we invite you to tweak away!
4. SWITCH-SELECTABLE CARTRIDGE TERMINATION CAPACITANCE on the front
panel yet!
Termination capacitance may be applied to each channel independently in 10 pF steps, up to 1100 pico-
Farads. The termination capacitance is present at the gain-stage inputs, and is not affected by input selector
or gain switch changes. For best accuracy consult your phono interconnect cable literature or manufacturer to
determine how much of the termination capacitance may be attributed to the cable. Then subtract at least that
amount from the target capacitive termination value.
If the interconnect manufacturer does not know the amount of capacitance per unit length that their wire
presents (!), then refer to the following example for a starting point: Typical phono interconnect cables will
exhibit self-capacitance on the order of about 30 pF per foot. If the interconnect cable is 3 feet (~ 1 meter) in
length, you may expect about 90-100 pF of input capacitance to be present due to the interconnect cable alone.
If the cartridge manufacturer species a load capacitance of 150 pF then it is best to subtract the cable’s portion, i.e. 90 pF. This yields a balance of 60 pF. Thus, the audition should start with the termination capacitance
switches set to 60 pF.
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