Radial Engineering PowerPre User's Guide
®
PowerPre
Microphone Preamp
500 Series Module
True to the Music
™
500
User Guide
®
www.radialeng.com
Radial Engineering Ltd.
1588 Kebet Way, Port Coquitlam
British Columbia, Canada, V3C 5M5
tel: 604-942-1001 • fax: 604-942-1010
email: info@radialeng.com
True to the Music
www.radialeng.com
Radial® PowerPre™ 500 User Guide
Table of Contents ........................................................Page
Feature Set .................................................................... 1
Overview ........................................................................ 2
Getting Started ............................................................... 4
Specifi cations ................................................................. 8
Block Diagram ................................................................ 9
Warranty ........................................................... Back cover
Congratulations and thank you for purchasing the PowerPre™ 500 microphone amplifi er.
The PowerPre is a unique 500 series preamp module designed to deliver the warmth of fully
discrete, transformer coupled electronics with the lowest possible noise.
This manual describes installing and operating your PowerPre 500 in the Radial Workhorse
or other 500 series module power racks. To take full advantage of the unique features that
have been incorporated, please read through this manual before using it. This will give you
a broader sense of its capabilities. If you have questions that are not covered in this manual,
please visit the FAQ section on our website. This is where we post answers to questions from
users. If you cannot fi nd the answer to your question please feel free to send an email to
info@radialeng.com and we will do our very best to respond as quickly as possible.
The Radial PowerPre 500 is warm, accurate and noise free. Enjoy.
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 rack is powered on. Hot
swapping can cause connection sparks at the card-edge connector that could send
damaging transients to other equipment. This also greatly reduces the life span of the
contacts. Damage due to hot swapping is not covered under warranty. There are no
user serviceable parts inside.
True to the Music
FEATURE SET
1. GAIN VU - 10 Segment LED bar provides visual peak signal
status by simulating the natural ballistics of a VU meter. Single
fl oating LED with peak hold lowers power demand for greater
effi ciency.
2. -15dB PAD - Expands the PowerPre’s capabilities by allowing
ultra hot signals from devices such as digital keyboards or
electronic drums to be interfaced without distortion.
3. 180º - Polarity reverse used to phase-align two microphones or
as a creative element when recording.
4. FILTER - 100Hz high pass fi lter removes low frequencies to
help eliminate excessive bass that can cause rumble. This
also helps clean up the recorded track by reducing ‘mud’.
Particularly useful when layering acoustic instruments.
5. OUTPUT - Adjustable gain control features dual taper
Accustate™ drive circuit that keeps background noise down at
all levels. Up to 55dB of gain adapts to all types of microphones
including condenser, dynamic and low output ribbon.
6. VOX: 3-position voicing switch lets you change the tonal
character of the preamp to suit. The linear setting delivers ‘true
clinical’ response for classical instruments; the breath position
adds ‘air and clarity’ to help vocals cut through the mix; punch
adds warmth to the bottom end to fatten up a track.
7. 48V - Phantom power for condenser microphone is equipped
with power-on LED and recessed to prevent accidental use that
could damage ribbon microphones.
8. MIC INPUT - XLR female connector is conveniently located on
the front panel and placed at the bottom to keep the cable out
of the way. Wired pin-2 hot following AES standard.
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 Workhorse.
10. XLR Output - Equipped with Hammond broadcast transformer
for smooth, warm response while being able to handle extreme
transients without choking.
11. GROUND LIFT (access at rear of module) - Disconnects pin-1
ground on the XLR input to eliminate ground loops. This special
feature should only be used when interfacing the PowerPre
with electrically powered instruments like a keyboard.
®
1
2
3
4
5
6
7
8
Rear Panel
9
10
11
Rear Panel
GND
Important!: Phantom power will be interrupted if the ground lift switch is set to the “LIFT” position. If your
condenser mic is not working, check to make sure this switch is in it’s normal “GND” position (see photo).
Note that the front panel LED for 48V phantom power will still illuminate when set to “LIFT”.
Radial Engineering Ltd.
1
PowerPre 500 Module
®
12
True to the Music
OVERVIEW
The Radial PowerPre is a state of the art microphone preamp that is designed to make
exquisitely detailed recordings quick and easy. You plug your mic in, adjust the level, set the
voicing and hit record. Over 18 months in development and a multitude of revisions were
invested in making the PowerPre this simple to use. But don’t let the simplicity fool you… the
PowerPre will easily outperform others that can cost much more.
On fi rst view, you will note that the XLR connector is on the front panel. This was done so
that you can have your 500 series rack right next to you and can connect a mic without
having to reach in behind. As a safety measure, the 48V phantom power switch is recessed
so that you do not damage your favorite ribbon mic. You will also notice that the PowerPre
is equipped with a -15dB pad for high output instruments, a 180º polarity reverse that can be
helpful when recording in stereo and a 100Hz high pass fi lter to gently eliminate unwanted
low frequency resonance.
Where the PowerPre really differs is in the audio circuit. Unlike the ‘attenuator’ that is found on
other preamps, the Accustate™ level control delivers maximum signal-to-noise at all levels.
This means that you do not have to worry about background noise polluting your recording
or having to auto-gate the track to remove unwanted hiss. You plug in and immediately get
spectacular results. And with the Hammond broadcast transformer, you can hit the PowerPre
with extreme level and it will take it without fl inching.
To add even more character to our super-hero, the Vox switch lets you introduce a little extra
air at the top or a little extra beef at the bottom. In other words, the effect is not mild or only
noticeable by those with golden ears, nor is it exceedingly prominent. This is not a sledge
hammer. This modest yet effective tool is designed to quickly let you tailor the sound of the
mic so that you can capture what you want. Have fun!
Accustate™ Input Control
Most professional preamps employ a switch to adjust the ‘volume
level’. This is because ‘volume’ controls are in fact not volume
controls at all… they are attenuators that reduce the input sensitivity.
This poses several challenges:
MIN MAX
First, when a normal potentiometer is used, the control tends to be very uneven whereby very
little change occurs between 7 o’clock and 4 o’clock. Then all of a sudden, the last 10% of
the control dramatically goes from soft to extreme. There is no graduation. This makes fi ne
adjustments diffi cult. As a work-around, the circuit designer will often ‘spread out’ what little
control he has to a wider scale for more rotation so that the range is at least usable. The trade
off is that the volume control does not actually go off.
As a compromise, many preamps
employ a 12 position rotary switch.
So instead of a smooth continuous
level control, the circuit designer will
predetermine 12 graduated steps to
give the user a ‘sense’ of scale. Because
the range between switch settings
is so large, some manufacturers will
add a second ‘fi ne tune’ control as yet
another work-around.
Radial Engineering Ltd.
12 POS SWITCH
6
5
4
3
2
2
7
8
9
10
11
12
1
2
1
NOISE FLOOR
3
7
6
5
4
PowerPre 500 Module
11
10
9
8
SIGNAL
SIGNAL-TO-NOISE RATIO
NOISE
Loading...