Radial Engineering PreMax 500 Series User manual

TruetotheMusic
www.radialeng.com
®
TruetotheMusic
®
User Guide
www.radialeng.com
Radial Engineering Ltd.
1588 Kebet Way, Port Coquitlam
British Columbia, Canada, V3C 5M5
tel: [phone] • fax: [phone]
email: [email protected]
PreMax
500SeriesPreampandEQ
™

WARNING NOTICE TO USER!
Although preventative safety measures have been designed into Radial 500 series
products we strictly advise against hot-swapping modules or plugging and
unplugging them when the Workhorse or other 500 series racks are powered on.
Hot swapping can cause connection sparks at the card-edge connector that could
send damaging transients to other equipment. This also reduces the life span of the
contacts. Damage due to hot swapping is not covered under warranty. There are no
user serviceable parts inside.

PreMax™ Preamp and EQ
TruetotheMusic ®
Radial Engineering Ltd.
Radial PreMax
500SeriesPreampandEQ
™
®
Table of Contents Page
Overview.......................................................................................................................1
Features .......................................................................................................................3
Making Connections.....................................................................................................4
Getting Started .............................................................................................................5
3 Band EQ....................................................................................................................6
Ominiport......................................................................................................................7
Specifications ...............................................................................................................8
Block Diagram..............................................................................................................8
Radial Limited Warranty ................................................................................Back Cover
INTRODUCTION
Thank you for purchasing the Radial PreMax, a combination microphone preamp and equalizer
designed to fit the more advanced Radial 500 series power racks and earlier designs made by
others. We invested a ton of effort during the development stage to make the PreMax quick to
set up and easy to use so that you can enjoy superb results each and every time you put it to
work. Plug in your favorite microphone, set the Accustate gain control for maximum signal-to-
noise and use the powerful three band EQ to shape your sound!
There are lots of little extras that are built into these fabulous devices. This is where reading the
manual is essential. Please take a few minutes to read through so you can take full advantage
of the feature set and maximize the performance.
If afterwards you have a question that is not covered herein, please take a minute to consult
the PreMax’s FAQ section on the Radial website. This is where we post questions and answers
from users along with updates. If you still have a question, feel free to send us an email at
[email protected] and we will do our best to answer in short order.
Now get ready to record with ease and confidence!

Radial Engineering Ltd. PreMax™ Preamp and EQ
TruetotheMusic
®
1
OVERVIEW
The PreMax is a combination preamp and three band equalizer jammed into a single wide
500 series module. By housing both processors together we can optimize the signal path,
maximum performance and minimize fuss. This accelerates setup times and eliminates many
of the challenges that make getting an instrument to sound right.
MIC
INSTRUMENT
LINE
OUTPUT
MIC
PREAMP 3-BAND EQUALIZER
The Preamp
The design begins with a state-of-the-art microphone preamp coupled with Radial’s unique
Accustategaincontrol.Unliketraditionalpreampsthatonlyachievetheiroptimalsignal-to-noise
when pushed to maximum,Accustate employs a dual wafer potentiometer that simultaneously
sets the input sensitivity and preamp gain so that the signal-to-noise ratio remains constant at
all levels. This is particularly important when recording in the digital domain where even the
slightest bit of noise can be audible.
NOISE FLOOR
MINIMUM GAIN - NARROW SIGNAL-TO-NOISE RATIO
MAXIMUM GAIN - WIDE SIGNAL-TO-NOISE RATIO
Traditional preamp gain Accustate preamp gain
The preamp is equipped with +48V phantom power for condenser microphones and active
direct boxes, a 180° polarity reverse to help phase align two mics when recording in stereo
and a handy high-pass filter that eliminates low frequency rumble to help clean up your tracks.
Visual monitoring is provided by two LEDs that display signal and peak output levels.
MIC
INPUT
OMNIPORT
LINE
OUTPUT
LED
METER
MID
PEAKING LOW
SHELVING
HIGH
SHELVING
MIC
PREAMP
ACCUSTATE
GAIN
+48
VOLTS 180° REV HI-PASS
FILTER
PREAMP EQUALIZER
When using the PreMax in a Radial 500 series power rack the Omniport is available and
functions as a high-impedance ¼” input for electronic instruments. For more information please
refer to the Omniport description later in this user guide.

PreMax™ Preamp and EQ
TruetotheMusic ®
Radial Engineering Ltd.
2
The Equalizer
Afterthepreamp has amplifiedthemic signal itfeedsa traditional 3bandEQ for toneshaping.
This great sounding EQ lets you gently boost the top end for more clarity, add warmth to the
bottom end, or cut back the mids on an overly aggressive instrument.Afront panel switch lets
you bypass the EQ to compare the pre-post effect.
We chose to employ a traditional old-school 3 band EQ to perform the task. This type of EQ
is super fast to use, sounds musical and is not as cumbersome as a parametric. We carefully
selected the EQ frequencies to sound musical and work with today’s production styles.
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The high frequency control makes it simple to add extra sparkle to a 12-string acoustic guitar
or reduce the shrillness of a violin. The low frequency control can boost the bottom end of a
male voice or be used to fatten a bass guitar. Cutting some mid-range can pull a track back
into the mix, while boosting mid-range brings it forward.
This straight forward equalizer makes it easy to get great sounds up in your monitors quickly.
A handy EQ-IN bypass switch lets you compare the sound of the track between the pre and
post EQ settings.

Radial Engineering Ltd. PreMax™ Preamp and EQ
TruetotheMusic
®
3
FEATURE SET
1. GAIN: Used to set the gain of the mic
preamp. Accustate gain control sets the
input sensitivity and gain at the same
time to optimize signal to noise at all
settings.
2. LED METERING: Signal and peak LED
meter provide visual feedback of signal
status and max output level.
3. 180° REVERSE: Inverts the polarity to
help phase align two microphones when
recording in stereo.
4. HIGH-PASS FILTER: Gently rolls-off
low frequencies below 100Hz to reduce
rumble which can muddy up a recording.
5. 3-BAND EQ: Low, mid and high
frequency controls with +/-12dB of boost
or cut are used for tone shaping.
6. EQ IN/OUT: Bypass control lets you
compare the tone of the original signal
without the EQ and the tone created
when the EQ is inserted.
7. MIC/INST: Toggles the input from the
balanced XLR on the rear of the power
rack to the Omniport ¼” instrument input
on your Radial power rack.
8. 48V PHANTOM: Power for condenser
microphones. Switch is recessed to
prevent accidental use that could
damage vintage ribbon microphones
or cause loud pops. The LED indicator
illuminates when the phantom power is
active.
9. OMNIPORT: Rear mounted ¼”
connector designated as an instrument
input to allow guitar and bass to be
recorded direct. Available when used
with the Radial Workhorse.
1
23
4
5
6
7
8
9

PreMax™ Preamp and EQ
TruetotheMusic ®
Radial Engineering Ltd.
4
MAKING CONNECTIONS
As with all audio equipment, always ensure levels are turned down and equipment is turned
off before making any connections or inserting the PreMax into a 500 series power rack. This
common practice ensures turn-on transients will not damage more sensitive components such
as tweeters.
Slide your PreMax module into the 500 series power rack until the card-edge on the board is
firmly seated into the slot connector on the main board. Care should be taken when inserting
the module to maintain correct alignment of the card-edge with the connector. After inserting
the PreMax into your 500 series rack, secure it using the supplied machine screws to ensure it
does not accidentally become dislodged during use. To prevent damage to the power rack, do
not over-tighten the mounting screws.
Most 500 series racks are equipped with balanced XLR connectors. When you insert the
PreMax into your 500 series rack it will automatically route the rear panel XLR connections to
the module’s input and output. This is augmented with ¼” TRS connectors if using the PreMax
in a Radial Workhorse 500 series power rack.The PreMax follows theAES standard with pin-2
(+) hot, pin-3 (-) cold. Most devices are wired this way but older vintage equipment should be
checked to confirm compatibility withAES standards.
Connect a microphone or direct box to the PreMax input using a standard XLR patch cable. If
you are using a condenser microphone or active direct box, turn on the 48V phantom power.
The switch is recessed to prevent accidental turn on. Use a small screw driver or paper clip to
push in the switch. A red LED will illuminate when phantom power is active.
Rear panel mic input and line output.
Radial Workhorse 500 rack.
INPUT
OMNIPORT
FEED
LINK
1
OFF
OFF
CARD SLOT 1
OUTPUT
OUTPUT INPUT
Connect the line-level output of the PreMax to your audio system so that you can audition the
PreMax. We recommend that you first listen to the PreMax on its own before combining with
effects or other signal processors until you have had a chance to familiarize yourself with the
preamp and equalizer functions. Using your own voice to test is best, as it gives you a familiar
starting place.
gg

Radial Engineering Ltd. PreMax™ Preamp and EQ
TruetotheMusic
®
5
USING THE PREAMP
Once you have the PreMax safely mounted in your rack
and patched into your recording system, set the controls
on the front panel as shown here on the right. All four
buttons should be set to their outward position. This ‘start
position’ bypasses the equalizer from the signal chain to
enable you to first set the preamp to optimize signal-to-
noise.
Power on the audio system and turn up the volume on
your monitors. Plug in your mic and slowly turn up the
preamp gain control while observing the LED meter. The
bottom green LED illuminates when the output level is
above -40dB and indicates the PreMax is working. The
top red peak LED illuminates when the signal is near
clipping. If it flashes on peaks, turn the preamp gain
down by about 10% to ensure a strong signal level
without clipping. Always test at a low volume to ensure
the PreMax is patched in and working. If you do not hear
any sound, check that your 500 series rack is patched
correctly. If you are using a condenser microphone,
ensure the 48V phantom power is turned on by checking
the red LED at the bottom of the front panel.
Using The 180° Polarity Reverse
When recording an instrument you may want to use two
microphones and two PreMax preamps at the same time
to capture the sound. Together, the mics can create a
timbre that a single mic cannot. One may be positioned
near the instrument while the second may be set further
away to capture the room’s natural ambiance. Engaging
the 180º polarity reverse on one PreMax can sometimes
achieve a fuller sound by aligning the low frequency
phase response of the two mics. (Devices like the Radial
Phazer take this to another level by allowing you to
adjust the phase incrementally.)
The 180º polarity reverse can also be used to correct the phase of older vintage equipment
that may have been made before the AES standard was established. Most equipment today
employs the standard with pin-1 ground, pin-2 hot (+), and pin-3 cold (-). Depressing the
180º polarity reverse switch will toggle pins 2 and 3 at the XLR input to compensate for non-
standard or vintage equipment.
Using The High Pass Filter
Ahigh-pass filter (low cut) is generally used in
the studio to clean up excessive bottom end
that can render recordings muddy and cause
some instruments to become indistinct. Bass
frequencies are so much longer and more
powerful than highs, so controlling them
can often be very beneficial. Live sound
engineers will often reduce the low end from
acoustic instruments to reduce resonance
and prevent run-away feedback.
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High-pass filter response
Minimum
Off (out)
Off (out)
0dB
0dB
Mic (out)
Bypass (out)
0dB
STARTING POSITION

PreMax™ Preamp and EQ
TruetotheMusic ®
Radial Engineering Ltd.
6
USING THE EQUALIZER
Once you have the preamplifier working, activate the equalizer
using the EQ-IN switch and begin testing the three EQ bands.
Each of the three bands uses an active EQ control capable of
cutting, or boosting the amplitude within the band’s frequency
range. The center, 12 o’clock position, is the neutral point or
0dB. Rotating the control clockwise from center will boost
frequencies. Turning it counter clockwise from center cuts them.
Start your experimentation with the high and low shelving
filters set at the 12 o’clock position. These filters affect the
treble and bass frequencies and offer 12dB of cut or boost.
These ‘shelving’ filters gradually increase amplitude from a
fixed frequency to the limit of the audio spectrum.
Low frequency EQ Mid-range frequency EQ High frequency EQ
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The mid-range is a constant-Q filter that forms a bell-shaped curve centered around the
middle of the audio spectrum. As the amount of boost or cut is increased, a wider band of
frequencies are affected and the mid-range begins to overlap and interact with the high and
low bands.
You can take advantage of the interaction between bands to produce an EQ curve that a
single filter can not achieve on it’s own. For instance, boosting the mid-range while cutting
high band can produce a complex frequency response that accentuates the high-mids but
rolls-off the hiss. Likewise, cutting the bass and boosting the mids will accentuate low-mid
frequencies while also cutting out low frequency rumble. Taking this further, you can employ
the high-pass filter in the preamp section to cut deep bass.
The mid-range is superimposed over the high and
low filters to show the frequency overlap between bands.
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BOOSTCUT

Radial Engineering Ltd. PreMax™ Preamp and EQ
TruetotheMusic
®
Omniport™ instrument input
If you are inserting the PreMax into Radial 500 series power rack, you can use the Omniport
as a high impedance instrument input to record electric guitar, bass or keyboards. Simply
connect to the PreMax via the Omniport jack using a standard ¼” instrument cable. Set the
MIC/INST switch on the front panel to the inward position to activate the Omniport.Adjust the
preamp gain and equalizer tone to suit and record as normal.
7
INPUT
OMNIPORT
FEED
LINK
1
OFF
OFF
CARD SLOT 1
OUTPUT
OUTPUT INPUT
Omniport input on Radial 500 series racks.
The MIC/INST selects between the XLR mic
input and the Omniport instrument input.
INST (in)