SMc Audio VRE-1C User manual

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Using your VRE-1C Preamplifier
Congratulations on your purchase of the VRE-1C Reference Preamplifier. The
VRE-1C is simple to setup and operate, but that simplicity belies an exceptionally
sophisticated design that includes a great deal of innovative thinking and the best
parts available today. Although reading this manual may not be necessary for
you to begin enjoying your VRE-1C, I urge you to take a few minutes to
familiarize yourself with the more novel aspects of its design.
Package contents:
the VRE-1C preamp
its companion remote control
its companion power supply
1 analog power link cable (custom designed and built for the VRE-1)
1 utility power link cable
a polishing cloth
owner’s manual
Unpacking your VRE-1
Your VRE-1’s box and packing have been carefully designed to protect it during
shipping. Please keep all packing materials - these may be important should you
ever need to store or ship your preamp again.
Both the VRE-1 and its power supply are placed in bags to protect their finish
during shipping. The power supply is finished in durable “powder coat” - a tough,
scratch-resistant finish. This may be cleaned with any sort of spray cleaner and a
paper towel, etc. The VRE-1 is built of Corian (a registered trademark of the
DuPont corporation - see www.Corian.com for more information) - a “solid-
surface” material often used in home construction. Corian is a very tough, stone-
like material that can withstand a lot of abuse, but the high polish on the VRE-1
chassis does require some care to maintain. Please use the polishing cloth
included for light cleaning, and avoid paper towels (which are slightly abrasive)
that may dull the finish over time. Any cleaning or polishing product suitable for
acrylic (or for Corian specifically) may be used, but "Pledge" spray polish works
very well for general maintenance. If cleaning is required first, a glass cleaner like
Windex and a soft rag should do the trick, followed by a shot of Pledge and the
polishing cloth. Clean the polishing cloth with your regular laundry as needed.
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Preparing for use - locating your VRE-1C
Your VRE-1 has a lot of wonderful attributes, and one of them is the fact that
neither it nor its power supply produce appreciable heat. This means that you
may locate your VRE-1 and its power supply pretty much wherever you wish,
although I recommend that you keep the VRE-1 at least one foot from any piece
of equipment that includes a transformer (including its own power supply). This
will minimize the possibility of picking-up any hum or radiated noise. The power
supply must be kept within the reach of its power link cables (5 feet, or about
1.5M) but may be located at any angle as you deem useful. Refer to the
addendum at the end of this manual for more information about the sonic effects
of equipment racks and isolation bases.
Situate your VRE-1 and power supply, then attach the supplied power link
cables. Their connectors prevent you from making a mistake in alignment - they
will only mate one way. Both are locking. Align the key of the utility power link
cable with its mating connector (Power 2), press it in fully, and screw-down the
locking collar (do not over-tighten). The analog power link (Power 1) uses a
special locking connection made by Neutrik. NOTE: The ends are color-coded,
and the RED-coded end connects at the power supply. With the release tab
in the up position, line-up the connectors and rotate the cable end slightly
counter-clockwise until it slides in. Press it in fully and rotate the cable end
clockwise until you hear the locking “click.” To disconnect, slide the locking tab
back and rotate the cable end counter-clockwise until it stops, and then pull it out.
Connect your source equipment and amplifier (using balanced connections if you
have the option). Leave your amplifier turned off for now and make the AC power
connection to the VRE-1. Check to see that the blue power LED is lit on the
power supply, and you should also see the front-panel LEDs for Input 1 and
Mute. Your VRE-1 is now on and ready for use. (Note: If you do not see the LEDs
light on both the power supply and VRE-1, please refer to the troubleshooting
section at the end of this manual.) There is no power switch because your VRE-1
is designed to stay on continuously. Simply unplug the AC cord if you need to
turn your preamp off (engage Mute first). Turn on your amplifier, and you are
ready to experience some incredible music reproduction.
Please Note: The VRE-1’s design includes a variety of practical safety features,
including a robust mute and power system. You may connect or disconnect the
power cables in any sequence, even while the power supply is “live” (always be
sure that Mute is engaged). Both power link cables are required for operation, but
nothing bad will happen if only one is connected - the VRE-1 simply won’t work.
So long as the VRE-1 is muted, you won’t hear anything from it. The Mute is
designed as a true “brick wall.” When it is engaged, nothing will escape the
preamp (mute is engaged by default when the power is off). Finally, even if the
power goes off or on unexpectedly while the VRE-1 is unmuted, you should hear
little or nothing in the way of pops or thumps.
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Front Panel layout
Source selection buttons: Sequentially selects one of 4 inputs. The
right-hand button increments (1-2-3-4) while the left-hand button
decrements (4-3-2-1).
Polarity inversion button and LED indicator: Sets system polarity
(absolute polarity, sometimes called “absolute phase”). When the LED is
off, system polarity is normal (non-inverted). Pressing this button inverts
signal polarity and lights the LED to indicate that system polarity is
inverted. Polarity switching is done at the user’s discretion and “correct”
system polarity is determined by ear.
Remote LED indicator: flashes to indicate the reception of valid
commands from the remote control hand unit.
Home Theater Bypass button and LED indicator: Press-and-hold this
button for 3 seconds to engage the Home Theater Bypass mode and light
the indicator LED. This adjusts the volume to a preset, user-programmed
setting, unique for each input. This is useful in Home Theater applications
and when doing critical listening that requires returning to a specific
reference volume level. Press this button again briefly to disengage the
HT Bypass mode. See the section on "System Programming" for further
detail.
Mute button and LED indicator: Pressing this button toggles the Mute
function. The LED will light to indicate that mute is engaged.
Volume control: Adjust volume with this detented encoder. Turning this
knob will adjust the volume up and down in .5dB steps. The encoder is
"free-wheeling" and will turn continuously without stops.
-------------------------------
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Rear Panel layout
Power connections 1 & 2: Power 1 is the analog DC supply via the
Neutrik connector, while Power 2 supplies DC power to the relays, lights
and Monitor Out buffer.
Main Outputs: The XLR jacks provide balanced output via the Jensen
transformers, while the unbalanced RCA connections are usually direct-
coupled to the JFET buffer amplifiers. This may be reconfigured if
necessary.
Output Ground Switch: Normally left in “float” position. This switch
connects the outer electrode of the RCA jacks to circuit ground (“ground”)
or leaves them unconnected (“float”). In some systems grounding the
outer RCA contact may be required to eliminate noise.
Monitor Out: Essentially the same as the “Tape Out” of the past, this
provides a buffer-isolated signal from the selected input. This output is not
controlled by the volume knob, and is useful for feeding a separate system
like a dedicated headphone amplifier.
Monitor Out Defeat Switch: In the interest of maximum purity of the main
signal path, the Monitor Out buffer may be switched off (defeated) if it is
not being used. Just switch this on or off as needed.
Circuit Ground Connector: This binding post offers access to the system
electrical ground if needed. There is normally no connection to this post.
Main Input Group: 4 pairs of inputs are provided, labeled 1 thru 4
(corresponding to the numbered front panel Input LEDs). Input 1 is a
dedicated balanced input with XLR connectors, while 2 thru 4 are via RCA
connectors. However, all of the inputs are actually balanced - all
connections go directly to the input transformers via “floating”
(ungrounded) lines. If you happen to have more than one balanced
source, custom XLR-to-RCA adapters are available to convert inputs 2
thru 4 to fully-balanced operation.
RCA Input Ground Switches: Inputs 2 & 4 may be grounded via these
switches if needed to eliminate ground-related noise (hum and buzz).
Leave these switches in the Up (float) position unless you experience a
noise problem that requires grounding that input.
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Remote Control Handset Layout
Standby: Puts your VRE-1C to "sleep," shutting down all functions and
LEDs. Press this button again to wake the unit up with the same settings.
Polarity: Toggles system polarity in the same manner as the front-panel
button.
Volume Up / Down: Pressing the upper button increases volume;
pressing the lower button decreases volume.
Mute: Pressing the center button in Volume mode toggles the Mute
function.
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Balance: Press the right button to shift balance to the right; press the left
button to shift balance to the left. Pressing the center button while in
Balance Mode will return balance to the center.
Input Select: Directly selects the numbered input of your choice (1-4 only.
Buttons #5 & 6 are not currently used.)
This is an "IR" (infrared) type remote control that must be pointed in the direction
of the VRE-1C to work properly. When the VRE-1C receives a valid command, a
red LED will flash in response to let you know that the remote control system is
working. If this LED does not flash, the preamp is not receiving commands from
the remote hand unit. Be sure the remote is pointed at the VRE-1C. If the unit still
does not function, check the 2 x "AA" batteries in the remote. You must remove
the 2 screws holding the bottom plate on the remote to access the battery carrier.
Use fresh alkaline or rechargeable type batteries only.
VRE-1C Operation
Ensure that all interconnect and power cables are properly attached. Turn on
your amplifier, select the proper input on the VRE-1C, and disengage the mute
by pressing the mute button on either the front panel or remote control (the blue
mute LED will turn off). You should hear sound at a moderate level (the volume is
set to a moderately low level by default on turn-on). Change the volume as
desired by using the front-panel knob or remote control. You can experiment with
system polarity by pressing the polarity button and listening to the result. This is
done by ear - choose the setting that sounds best to you. Absolute polarity
effects vary considerably among different recordings - you may hear an obvious
effect, or very little. Do not be concerned - just use the setting that sounds best
overall to you. When you have finished listening, pressing the Mute or Standby
buttons will prevent any signal from leaving the VRE-1C.
System Programming
Your VRE-1C includes 2 user-programmable level functions: the Balance control
and the Home Theater Bypass (HT Bypass).
Balance Control: A balance offset may be programmed into your VRE-1C if
desired. Using the remote control, simply shift the balance setting by the amount
desired, and then press either of the volume control buttons. The Balance LED
(either "L" or "R") will blink once to show that it has received the programming
command, and then will remain lit until the balance offset is cancelled.
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Home Theater Bypass: This function allows the user to program a specific
volume setting for each input that is recalled when the HT Bypass mode is
engaged. This can be done only by using the front-panel "HT Bypass" button.
Select the input you wish to program. Press-and-hold the HT Bypass button for 3
seconds - the LED will light and the bypass mode is engaged. Release the button
briefly, then press-and-hold it in. Adjust the volume setting to the desired level
and release the HT Bypass button. The LED will blink once to let you know the
level has been programmed. This is the volume setting that will be recalled for
this input whenever you engage the HT Bypass mode. Use the above procedure
to reprogram this setting any time you wish.
Using the Home Theater Bypass Function: This programmable function is
useful any time you need to return to a specific volume setting. The primary use
is in a home theater setting where the VRE-1C is part of a high-performance
multi-channel playback system. In this case, a surround processor (or something
similar) is the system controller for multi-channel playback, while the VRE-1C is
dedicated to the main front left and right channels for 2-channel stereo playback.
The left-front and right-front outputs from the surround processor are fed to one
of the VRE-1C's inputs. Using the surround system setup tools, a reference-level
signal is fed to each channel for adjustment to the proper volume. Use the
programming feature detailed above to set and program the proper reference
volume setting for this input on your VRE-1C. When multi-channel playback is
desired, select the proper input on your VRE-1C and engage the HT Bypass
mode. The preamp is automatically switched to the programmed reference
volume setting, and the surround processor is then used to control the overall
system level. Note that you can still make independent adjustments to your VRE-
1C while in this mode, so you can have a bit more or less volume from the main
left and right channels "on the fly" if you wish.
This mode is also useful if you are doing listening comparisons and need to be
able to return to a fixed reference volume. You can even use this mode to
"normalize" the volume level among all 4 inputs. This can be done by ear (with
care) or with a measurement tool of some sort - an SPL meter or voltmeter and
reference tone. This way you can switch between inputs and hear a constant
reference volume which can be very useful in doing listening comparisons.
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VRE-1C Design Highlights
Your VRE-1 is the product of many years of careful research into all aspects of
preamplifier behavior - circuit topology, parts performance, physical layout,
chassis materials, and power supply design. After many years in the audio field
dealing with equipment that colors or changes sound, I wanted to develop a
preamplifier that would impose no character of its own, acting as a transparent
window onto the original music and recording. Unlike past attempts that were
often characterized as “cold” and “analytical” sounding, my development work
has been guided by an unwavering commitment to deliver the warmth and soul of
music as it is recorded and heard in live circumstances. What I’ve achieved is a
synthesis of the best attributes of passive circuits (tonal neutrality, natural
harmonic texture, freedom from noise and active-circuit distortion) with the best
characteristics of active preamps (great dynamics, vivid clarity, wide-open
dimensionality, outstanding bass foundation and slam) as well as the relaxed
musicality of the best tube designs.
Let’s address the issue of tubes for a moment. I have experimented extensively
with tubes, both in the preamp circuitry and in the power supply. In my
experience, tubes simply cannot deliver the degree of tonal neutrality and low
noise that I demanded for the VRE-1. My goal was not to make yet another “good
sounding” preamp, but rather to deliver an absolutely transparent window onto
the original recording or master tape. Tubes simply do not fit this goal.
My listening tests led me to an exceptionally transparent JFET buffer circuit with
no gain which, when paired with my choke-filtered power supply, produces
unparalleled overall performance. When I found the right set of coupling
transformers (Lundahl on the input; Jensen on the output), the last pieces of the
puzzle fell into place and the VRE-1 was born. Its transformers act as a kind of
near-ideal load on the input and confer that magic tube-like musicality. They also
act as a “brick wall” filter against DC and RFI contamination. In addition, they
allow the VRE-1 to be configured for voltage gain (up to +6dB) if it is needed.
Thus, the VRE-1 is a “passive” preamp -- but with gain.
The Volume Control: This is the heart of any preamplifier. For many years I
relied on a custom-built, 31-step control based on a Shallco rotary switch. This
was the best sonic performance available at the time, and has only recently been
superseded by the new volume control in your VRE-1C. My goal was to create a
remote volume control that was *at least* as good as the Shallco switch version.
After a long period of research, I am happy to say that this new control actually
outperforms the Shallco, and is the first remote system in my experience to do
so. In addition, this new design gives the user far greater resolution than any
mechanical switch - 100 steps with -70dB of attenuation. I have arranged the
attenuation ladder for 1dB each at the top and bottom 10 steps, and .5dB each in
between (the majority of the useful range). Accurate balance adjustment in .5dB
10

steps is also included. I believe this design delivers sonic performance beyond
anything else available today.
Finally, all of the parts and materials used to build your VRE-1 are the best
available. A partial list includes parts from Lundahl Transformers, Jensen
Transformers, Stillpoints vibration control, Avel-Lindberg, Duelund Coherent
Audio, Audio Note, Vishay, Van den Hul, Shunyata, Stealth capacitors, Oyaide,
WBT, Neutrik, EAR Specialty Composites, Vibrapod, and DuPont Corian.
Your VRE-1 delivers the following performance attributes:
Perfectly coherent clarity: seamless character top-to-bottom, with no
region emphasized or depreciated, with no sonic vagueness, muddiness,
smearing, or veil.
Top-to-bottom transparency: that “see-through” quality that gives you
the feeling of looking across the space and venue of the original recording.
Effortless dynamic expression: from the quietest passages to the
loudest, the VRE-1 portrays music’s full dynamic power and subtlety --
from the thunderous strike of a drum to the nearly subliminal shift in a
singer’s breath.
Pinpoint focus and localization of instruments and voices within a 3-D
sound field – exquisitely clear individualization of musical lines.
Deep emotional connection with the music: perhaps the most elusive
and important quality of all.
The ability to achieve all of the above at any volume level.
Elegant simplicity of design with intuitive control operation.
A beautiful, non-resonant chassis (solid-surface-technology) which
makes an important contribution to its stunning performance.
Safe, reliable, low–voltage operation generates practically no heat.
Absolute reliability and stability of performance over time. The VRE-1
will always ready to deliver beautiful music, whether it is new or many
years old.
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The Power Supply
The VRE-1’s companion power supply provides carefully tailored DC power for
the proper operation of your preamp. The “Power 1” connection provides +/- 24
VDC of choke-filtered, unregulated power, while the “Power 2” connection
provides +/- 24 VDC of fully regulated power for the relays, LEDs, and Monitor
Out buffer amplifier.
Power supply design is critical to superior performance. In a very real sense, it is
the power supply we are hearing when we listen to music. One of the keys to the
VRE-1’s superiority is that its JFET buffer circuitry does not require a regulated
supply, so this source of signal degradation was eliminated. Voltage regulators
are very much like amplifiers, and all of the same rules of sound quality apply to
them. Eliminating this regulator stage allows the VRE-1 to get that much closer to
being a true “window on the performance.”
The VRE-1 supply uses the finest quality parts I have found through careful study
and experimentation: a superb toroidal power transformer, soft-recovery diodes,
outstanding chokes from Lundahl, superior capacitors, resistors, and wire, and
selected damping feet. The critical analog power-link cable is custom-made for
the VRE-1 by Absolute Fidelity Interface (absolutefidelity.com). This was chosen
after lengthy listening evaluations with a wide variety of cable options. Even the
AC inlet is chosen for superior clarity and transparency. Each power supply is
“voiced” by ear before delivery, which involves listening to the various
permutations of transformer secondary wiring. Its design and construction is an
exercise in total “overkill” - its current capability vastly exceeds the requirements
of the VRE-1, but I feel this translates into superior performance and reliability.
Literally, only the best will do.
Chassis and Feet
Every aspect of an audiophile component’s design affects its performance to one
degree or another, and this is true of chassis materials as well. I discovered long
ago that different metals (aluminum, steel, stainless-steel, copper, brass, etc.)
produced different sonic results with a given circuit, and this led to my use of
aluminum and copper-plated steel as preferred chassis materials. However,
various experiments I did in the course of developing new designs began to
suggest that eliminating metal altogether might produce even better results. This
led to experiments with Nylon, Delrin, different types of wood, and finally to solid-
surface synthetic materials. These materials are more difficult to work with than
traditional metals, but I consider the results to well worth the effort. The VRE-1’s
chassis is much more inert mechanically than traditional designs, and the
elimination of metal does away with certain colorations that get in the way of true
transparency.
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Please Note: The VRE-1 is a hand-built work of “industrial art.” It is a beautiful
object, and a great deal of effort has gone into its creation. Ironically, because it
is hand-made, you may find small blemishes that do not occur in the routine
perfection of mass-marketed consumer goods. We believe you’ll accept these as
part of the unique personality of your VRE-1.
Your VRE-1 comes with a set of high-quality damping feet from Vibrapod.
However, you may wish to experiment with other types of feet. Any change in the
feet will affect sonic performance, and it is up to you to decide if the change is
worthwhile. The best accessory feet I have experience with are the Apex feet
from Grand Prix Audio and the Stillpoints isolator system. CAUTION: Vibrapod
Isolators may blemish certain finishes. Use drink coasters, playing cards, or
other thin pieces of paper or plastic under them to protect your fine furniture.
Interconnect Cables
The subject of interconnect cables is important because they can have a
profound impact on your system’s performance. Your VRE-1 has been designed
to be compatible with all types of cables, but choosing the right set of cables can
enhance your sense of involvement and your listening pleasure. Unfortunately,
there is no way to predict which cables will work best for you, and the fact that I
use a particular brand is no guarantee that they will work as well in your system.
You must evaluate cables by listening to them in your own system, and you must
not allow yourself to be overly swayed by reviews and other opinions. Trust your
own ears and your own judgement.
Break-in Period
The notion that audio equipment changes how it sounds or “breaks-in” over time
is controversial in some circles (much like everything in audio), but it is very real
to me. It is my experience that new pieces of equipment undergo a process of
change that may take a few days, or even a few weeks to complete. The exact
reasons why are endlessly arguable, but include electrical, thermal, chemical,
mechanical, and psychological effects. Honestly, I am not interested in debating
the reasons why, but I do want to make you aware of the process.
The break-in phenomenon has become more of an issue in recent years
because the latest high-performance parts seem to take longer to fully break-in.
Some newer parts (like carbon wire) take little or no time to sound their best, but
the great majority of new parts I have discovered take quite a while to fully reveal
themselves. A few parts, like the Lundahl amorphous-core transformers, take an
unusually long time - up to several weeks.
This is important because I cannot fully break-in your VRE-1 before shipping.
Your preamp has been thoroughly tested and listened-to, but this is just the
beginning. I make every effort to present you with a good initial impression, but
13

beyond that it is up to you to complete the break-in process, and to understand
that it will take time.
Break-in is a process of using your equipment - not simply leaving it turned on.
You must have something playing (music or some sort of break-in signal) to get
the job done. I feel that playing music normally works perfectly well, but there are
special CDs and LPs made as “break-in discs” that are favored by some. Check
with your audio dealer or music supplier if you are interested in these.
The main thing is to understand that it will take some time for your VRE-1 to
realize its full potential, and I urge you to relax and enjoy listening to music while
it breaks-in, warms-up, settles-down, or whatever you want to call it.
Specifications (as usual, subject to change)
VRE-1 PREAMP
Gain (factory adjustable) --------- +0 dB (unity gain), or +6dB (typically set at +6dB gain)
Bandwidth -------------------------- +/- 3dB <5Hz - 170KHz (varies with gain setting)
Input impedance --------------- 10KOhm
Output impedance ------------ 50 Ohms @ 0dB gain / 200 Ohms @ +6dB gain
Power consumption -------- 10W maximum
Dimensions ------------------------- 17.5”Wx 12.75”Dx 5”H(includes hardware & feet)
Weight ---------------------------------- 25 lbs
VRE-1 POWER SUPPLY
AC Mains fuse -------------------- T1A* @ 115VAC / T.5A* @ 230VAC
*Refer to the addendum on using your VRE-1 for further information on fuses.
Dimensions-------------------------- 10.25”W x 9.5”D x 3.625”H
Weight ---------------------------------- 11 lbs
Total Shipping Weight - Approximately 42 lbs
Troubleshooting
Problem: No sound, no lights, no nothing.
Solution: Check your AC power connection to the wall outlet to make sure you
are getting power; check the AC Mains fuse to see if it is blown - replace if
necessary.
Problem: You have lights and hear the relays click, but no sound.
Solution: Your analog power link cable may not be connected properly - check for
proper cable connection. Check the obvious - is your amp turned on? Correct
input selected? Source playing? Check the interconnect cables to and from your
VRE-1. Be sure you have selected a working input.
14

Acknowledgements
This project has been in development for a long time, and I sincerely thank
everyone who contributed in any way to its success. However, there are a few
people I would like to point-out for their special contributions…
Jim Merod - For his to-the-point observations and criticism, and his
indefatigable efforts on behalf of music, musicians, and the audio
community.
Kris Jeter - His hard work keeps the wheels turning here at SMc Audio,
and his good humor makes the work go smoothly.
Carl and Lena Carpenter / Carpenter’s Fine Woodworking - Their
precision machining work on the original wooden prototypes and
subsequent Corian models made this project a reality.
Jerry Boncer - For all of his help in the past, and for his original design of
the JFET buffer circuit that made its way into the VRE-1.
Conrad Lindberg - For all of his help with circuit development and board
layout, and numerous practical suggestions.
Lundahl Transformers - For their enthusiastic support and useful
technical insights.
Paul Wakeen / Stillpoints - For providing the amazing standoffs & feet.
Gary Koh / Genesis & Absolute Fidelity - For his insightful feedback
and his incredible Absolute Fidelity Interface Cables.
929 El Pajodo Place
Vista, CA 92084
Tel: [phone]
[email protected] / www.SMcAudio.com
Represented worldwide by:
The Lotus Group
Novato, California, USA
www.lotusgroupusa.com
415-897-8884
15

Getting the most from your VRE-1 preamplifier - a user’s guide
If you want to get the best out of your VRE-1, put the best into it.
I have chosen to not include a standard AC cord with the VRE-1. It is my
experience that the AC cord is an integral part of the sound of your VRE-1, and I
suggest that you use the best power cord you can find. Your VRE-1’s
amplification circuitry may be thought of as a sort of valve that modulates the
power supply, and it is the quality of the power supply that you actually hear. I
have spent a great deal of time and effort in developing the VRE-1 and its power
supply, and I have examined every detail - right down to the fuse. A great
aftermarket AC cord is a must for getting the best-possible performance. I
do not include an aftermarket cord for several reasons, including matters of
personal taste, system synergy, and cost.
My own experience includes cords from Absolute Fidelity Interface Cables (my
personal reference), Kubala-Sosna (“Emotion” and "Elation"), Acoustic Zen (the
“Gargantua”), Furutech, Magnan Audio (the "Signature" Power Cable), and
Shunyata Research, to name a few. These are all excellent cords, but each has
its own personality and may or may not work well in your system. Please take
some time to do your own evaluation and you will be rewarded with the best-
possible performance from your VRE-1.
Audiophile fuses are a relatively new product offering, and I have experimented
with several different makes. As of this writing, I have a strong preference for
fuses by Furutech, and that is what I deliver in the VRE-1. However, Furutech
fuses blow more readily than other types, so I have switched to 2A for 115V
models and 1A for 220-240V models to avoid nuisance fuse blowing.
Beyond the power cord (and, obviously, your interconnect cable choices) there
are matters of chassis damping and isolation to consider. Your VRE-1’s Corian
chassis is quite inert on its own, and I have fitted both it and the power supply
with excellent damping feet. Still, the fact remains that your choice of stand and/
or accessory feet will affect performance. In my own system, I have chosen
isolation systems from Grand Prix Audio (the “Monaco” series) and their
outstanding “Formula” carbon-composite shelves. I can also recommend the
Stillpoints racks and feet. My experience suggests strongly that you will not hear
everything your VRE-1 (and your other equipment) has to offer unless you use
an isolation stand system of similar quality. Your choices may differ, but please
give some thought to this critical part of your system and its sonic effect.
The Corian chassis is both heavy and inert, but you may still wish to experiment
with added weight. Some piece of concentrated mass about the size of a book,
for instance - like a piece of marble, granite, or similar stone - may provide a
noticeable sonic benefit. Be sure to protect the Corian with some soft material.
16

Earth Grounding Options
Your VRE-1C provides several options for making connections between earth
ground and the preamp circuit ground to obtain the best results and lowest noise
in your system. A 3-position switch is located beside the AC Mains fuse (see
diagram below) which provides options for the connection between earth ground
and circuit ground: Float: (switch UP) isolated connection via an RC network
consisting of a 100 Ohm resistor in parallel with a .01uF capacitor, Ground:
(switch down) direct (zero-ohm) connection, and Off: (switch centered) no
connection. (For safety reasons the earth ground remains connected to the
power supply chassis at all times.)
Please note that the use of a 3-wire grounded AC cord assumes that an
appropriate earth ground connection is provided by your house AC wiring.
Your VRE-1C will operate regardless of the position of this switch. However, I
suggest that you experiment with the 3 settings. It has been my experience that
the Float (UP) setting typically gives quiet operation and optimum sonics, but the
situation may be different in your system. Earth ground interactions among
components can be complex, and you may hear some hum / buzz until you find
the right setting for your equipment.
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input Ground Switching
As previously noted, the VRE-1's inputs are all balanced, including the RCA-jack
inputs. This system works very well in practice, but there have been some rare
cases where the connection of an unbalanced source has led to noise problems
(hum & buzz). I have added individual “float / ground” switches to inputs #2 and
#4 to solve this issue. This solution is incorporated into current production units
and may be retrofitted into any earlier VRE-1.
The photo below shows the new switch layout:
Normal operation is to leave the switches up in the “float” position unless a noise
issue is encountered with a particular piece of source equipment. In this case,
moving the switch down to the “ground” position (for that input only) should
eliminate any noise caused by incompatible grounding.
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XLR-to-RCA balanced input adaptors
As stated earlier, all of the VRE-1’s inputs are actually balanced. If you have
more than one balanced source and wish to take full advantage of its balanced
mode of operation, I can provide custom-built adaptors to allow for this. Here is a
photo of what they look like in operation:
photo by Frederic Beudot for 6Moons.com
I choose silver-plated Neutrik XLR cable-mount female connectors, WBT Next-
Gen silver cable-mount RCAs (#0110AG), and Shunyata wire for the
connections. A separate 22ga wire is used for the XLR pin-1 connection to
chassis ground, and I terminate it with a stacking-type banana plug to facilitate
the use of multiple adaptors.
If you prefer, you can build them yourself. Connect the wires as follows (note
that these are NOT wired like industry-standard XLR-RCA adaptors):
XLR pin 1 - flying lead to stacking banana plug (shield ground)
XLR pin 2 - to RCA center pin (positive hot)
XLR pin 3 - to RCA outer case (negative hot)
You can add whatever number you need, including converting all inputs to full-
balanced operation if that is what your system requires.
Steve McCormack, designer - SMc Audio
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