SPL Charisma 9733 User manual

Model 9733
Manual
Dual Channel Tube Processor

SOUND PERFORMANCE LAB
by Hermann Gier and Paul White
Version 1.2 – 1/1999
The information in this document has been
carefully verified and is assumed to be correct.
However Sound Performance Laboratory (SPL)
reserves the right to modify the product
described in this manual at any time. Changes
without notice. This document is the property of
SPL and may not be copied or reproduced in
any manner, in part or full without the autho-
rization of SPL.
Limitations of Liability:
In no event will SPL be liable for any damages,
including loss of data, lost profits, cost of cover
or other special, incidental, consequential or
indirect damages arising from the use of the
unit, however caused and on any theory of liabi-
lity. This limitation will apply even if SPL or an
authorized dealer has been advised of the
possibility of such damage.
SPL electronics GmbH
P.O. Box 12 27
D- 41368 Niederkruechten, Germany
Phone: +49 - 21 63 / 9 83 40
Fax: +49 - 21 63 / 98 34 20
eMail: [e-mail]
www.spl-electronics.com
©1999 SPL electronics GmbH. All Rights Reserved.
CHARISMA
Model 9733
Manual

3
Contents
Foreword................................................................................ 3
Thanks ................................................................................... 3
Introduction........................................................................... 4
Operation safety.................................................................... 4
Connections........................................................................... 5
Control Elements
DRIVE.......................................................................... 6
MAX/PROCESS LED´s................................................... 6
CHARISMA.................................................................... 7
OUTPUT....................................................................... 7
BYPASS........................................................................ 7
Applications.......................................................................... 7
Normal Processing................................................................ 8
Set-up positions....................................................... 8
Getting started.......................................................... 8
The CHARISMA control................................................ 8
Tip offs...................................................................... 9
Extreme Processing.............................................................. 9
Tip offs...................................................................... 9
Power Supply.........................................................................10
Specifications.........................................................................11
Warranty................................................................................12
Dear customer,
Thank you for the confidence you have shown towards SPL
electronics GmbH by purchasing the SPL CHARISMA. You have
decided to use a tool of high performance which sets you in the
position to have faster success and a better sound quality in
your music productions. As a typical SPL unit the CHARISMA
combines exemplary specifications and high manufacturing
standard with excellent sound quality to provide you a precious
component for studio purposes.
Please read this manual carefully to ensure you have all the
information you need to use the CHARISMA.
We wish you every success with your new CHARISMA.
Your SOUND PERFORMANCE LAB-Team
I would like to start with my thanks to all our staff, who
created what is to be described here. The importance of their
exceptional qualification and talents cannot be overestimated.
A very special “thank you” goes to Manfred Reckmeyer,
whose longterm experience in tube technology including
custom modifications of tube gear for many artists made this
product possible.
Our products are often tested and compared in many publica-
tions and by our customers themselfs and constantly valued
with best results. I would like to pass on this broad appreciation
to those, who deserve it – my excellent colleagues.
Hermann Gier
Foreword
Thanks

4
CHARISMA is a 2-channel tube processor designed to improve
the power, punch, dynamics and the subjective loudness of the
signal being processed.
Designed to introduce a subjective tonal warmth and a
smooth bottom end into digitally recorded material, CHARISMA
is a joint development between SPL and Manfred Reckmeyer,
the designer responsible for the development of the 8-channel
CHARISMA.
CHARISMA represents a solution that far exceeds the mere
simulation of tape saturation, and CHARISMA´s tube saturation
characteristics can be fully controlled by the user. The concept of
operation is simple. Each CHARISMA channel has three potentio-
meters: DRIVE sets the drive level to the tubes, CHARISMA adjusts
the tube saturation characteristic, and OUTPUT sets the output
signal level.
CHARISMA also helps to prevent overload and clipping on digi-
tally or analogue recorded tracks. You should use CHARISMA
while recording before your digital recorder in order to clip-
protect your recording (e. g. limiting peaks from live-recorded
drums or reducing sharp “esses” from vocals). CHARISMA gives
your signals more clarity, transparency and presence. Each part
of the mix, instrument or vocal can easier be distinguished and
located. Using CHARISMA on single instruments alone lets those
signals stick out of the mix. CHARISMA also helps you to place
vocals in a densed playback and maintaining their presence.
We will start with general safety hints, followed by the
connections on the rear panel. We then take a look at the
controls on the front and go on with practicals tips for the usage
of CHARISMA.
The housing of CHARISMA has the standard 19"-EIA format and
occupies 1U (44 mm) in your rack. When installing the unit in a
19"-rack, the rear side of the unit needs some support, especi-
ally in a touring case.
CHARISMA should not be installed near units which produce
strong magnetic fields or extreme heat. Do not install CHARISMA
directly above or below power amplifiers or digital processors.
This eliminates problems which could result from interfering
high-frequencies such as clock frequencies, MIDI or SMPTE
control signals.
Check that the voltage details quoted on the back panel are
the same as your local mains electricity supply. Use a minus (-)
screwdriver to set the voltage selector to the voltage for the
area in which the unit will be used.
Never cover up the ventilation slots on the top of the unit. If,
during operation, the sound is interrupted or indicators no
longer illuminate, or if abnormal odor or smoke is detected, or
if liquids are spilled on the unit, immediately disconnect the
power cord plug and contact your dealer.
Only clean your CHARISMA with a soft, lint-free cloth. Use only
standard cleaning agents. Never use alcohol or paint thinner,
because they may damage the finish.
Introduction
Operation safety

5
Before connecting CHARISMA switch the power off at all
connected units.
CHARISMA is fitted with both XLR-connectors and TRS stereo
jacks for balanced operation, though the jacks may be used with
unbalanced connections simply by plugging in mono jack-plugs.
The level difference that normally occurs when a balanced
input or output is used unbalanced is automatically compen-
sated for.
Should the need arise to use the XLR connectors in an unba-
lanced system, pin 3 of the XLRs should be grounded. Inserting
a mono jack also unbalances the XLRs:
Both output stages operate in parallel, so it is possible to
connect two different destination units simultaneously, for
example to record to two different media at the same time or
split the output between a mixer and effects processor.
However, only one type of input (jack or XLR) should be
connected at a time – the CHARISMA is not intended to be used
as a mixer!
To ensure optimal signal quality, SPL has developed a new
hybrid-component balanced input/output stage using all laser-
trimmed resistors with a tolerance of 0.01%. This approach has
resulted in an exceptionally high CCMR (common mode rejec-
tion); 100dB at 1kHz and 80dB at 10kHz. As a precaution,
before connecting the CHARISMA switch off the power to the unit
and to all connected units.
Other rear panel connections and switches:
- Voltage selector: 220-240V/50Hz or 100-120V/60Hz
- CSA/UL approved 3-pole power plug
- GND-Lift switch
Included in the packaging are:
- 3-wire, U-ground, power cord
- Owner´s Manual
- Warranty card
- SPL catalogue
Connections
12
3
Pin wiring: XLR connectors
1=GND 2=Hot(+) 3=Cold(-)
Pin wiring: stereo-jack plug
Tip=Hot(+) Ring=Cold(-) Sleeve=GND

6
Setting the drive level to the
tubes
PROCESS = processing starts
MAX = max. saturation
Examples:
– with snare or kick drum you
can use heavy distortion (MAX
LED illuminates)
– with layer sounds you
should be very careful! Only
use very little distortion if any
(PROCESS LED rarely)
Control elements
The DRIVE control sets the drive level to the tubes. DRIVE values
can be adjusted between -oodB and +24 dB.
You have control over the tube´s onset of saturation to find the
optimum point of processing. The higher the DRIVE, the more tube
harmonics are being generated. At the same time, limiting gets
stronger, increasing the density of the tube distortion.
Start off with the DRIVE set at 0 dB. Now the input level is
equivalent to the level driving the tube electronics. When you
increase the value, you will get a more intense tube processing
and the output volume rises. To compensate this use the OUTPUT
control (4).
The PROCESS LED illuminates when CHARISMA starts its tube
processing. The tubes are starting to generate their typical sound
and harmonical structure.
The MAX LED indicates that the processing has reached its
maximum position. Now the tube is fully saturated and the
typical limiting effect occurs. Increasing the DRIVE results in more
tube distortion.
IMPORTANT: When you start to process a sound with heavy
transients and attack, like a snare or a kick drum, you can drive
the tubes into heavy saturation before you start to hear the
tube´s distortion. When the PROCESS LED starts to illuminate you
hardly hear a change. Drive the tubes into heavier distortion so
that the MAX LED illuminates frequently and the tube processing
becomes audible.
On the other hand, when you process layer sounds or almost
sinewave-like sounds you will sometimes hear the tube´s distor-
tion even before the PROCESS LED illuminates. The CHARISMA effect
is sometimes unpleasant on layer sounds! So, set the DRIVE level
depending on the character of the sound you want to process. Our
hearing detects overtones on sinewave-like signal immediately as
unpleasant distortion, whereas squarewave-like sounds can be
heavily distrorted and still remain pleasing to the ear.
Note: Do not set the DRIVE controls to identical scale settings
and expect the tubes to act identical when different source
characteristics are present at the inputs. Trust your hearing.
Drive
2
1
Max/Process LEDs
132
45

7
Selecting the sound
character of the tube proces-
sing
Monitor the peak level to set
the OUTPUT level correctly!
Output
3Charisma
4
Bypass
5
CHARISMA can be used everywhere, where audio signals might
benefit from the excellent tube sound. The CHARISMA concept is
ideal for use in conjunction with digital multitrack or hard-disk
recorder systems, but it can equally be used with analogue tape
or DASH machines.
Making use of the typical tube harmonics and saturation
sounds, as well as the natural tube limiting effect, while recor-
ding, is of benefit to almost any signal – indeed there´s almost
no limit to the applications. The sonic implications can best be
characterized as gaining more presence, punch, and warmth.
In the MIDI studio, CHARISMA is ideal for processing single
tracks such as keyboard or sampler sounds as well as vocals. In
this application, the CHARISMA is inserted into the mixer´s chan-
nels inserts or directly between the source and the desk.
The most flexible way to use CHARISMA in the studio is to wire it
Applications
This unique control varies the tube sound and allows you to
create varying sound characteristics from SOFT to HARD.
Creating different tube sounds results in varying harmonical
structures and adjustments in the SOFT control range bring in
the harmonical distortion and the tube limiting very slowly (you
can compare this with the soft-knee characteristic of a limiter).
In comparison to the HARD control range the SOFT effect starts
off at relatively low levels. The sound becomes smooth and
warm, is a little softer, and contains more harmonic distortion
than the HARD sound.
In the HARD control range CHARISMA operates comparable to
the hard-knee characteristic of a limiter. The processing starts
with full effect at one point whereupon the signal is sharply
limited, and at this point, the sound becomes punchy and crispy.
Depending on the selected characteristic and intensities, a
readjustment of the DRIVE control may further emphasize the
desired effect.
The OUTPUT control sets each channel´s output gain to
compensate for the level increase when the DRIVE control has
added level to drive the tube circuitry.
Use a peak meter to set the OUTPUT level correctly. If you
insert the CHARISMA on your console or patchbay without having
control over the peak level you will end up with less peak level
although the loudness is the same. This is because of the
limiting effect of the tubes. CHARISMA is designed to increase
loudness by maintaining the same peak level and to improve
bit resolution on digital recording systems.
The bypass switch switches each CHARISMA channel in and out
of processing (hard-bypass), and the bypass switch is labelled
according to channel number.

8
into the patchbay. That way you can decide, whether it should
be used while recording or later during mixdown – or simply
inserted into specific channels. Processing subgroups is another
interesting application. Using CHARISMA while recording to
digital is the most beneficial application as the tube limiting
prevents clipping.
Creating effects like tape saturation,
Increasing loudness,
Improving presence.
You control the sound of CHARISMA with the DRIVE and
CHARISMA controls. The OUTPUT control is used to compensate for
the level increase when the DRIVE control is set higher than 0dB.
Set the DRIVE to zero and CHARISMA to center position.
Set the OUTPUT control fully clockwise (0 dB).
Input and output levels should be identical now. Check this by
depressing the bypass switch, labeled with the channel number.
Turn the DRIVE control slowly clockwise. You start to drive the
tube into saturation. The level increases. Compensate this by
turning the OUTPUT control counter clockwise.
The PROCESS LED illuminates when the processing starts.
Depending on the source characteristic you will hear the
CHARISMA process much more intense with sinewave-like/layer
sounds. When processing these sounds the PROCESS LED should
illuminate rarely. When processing squarewave-like/transient
sounds you can drive the tubes harder. The PROCESS LED may
illuminate constantly and the MAX LED may also light up
frequently. The MAX LED tells you that the maximum satura-
tion of the tube is reached.
Now, check the peak level meters on your playing and recor-
ding unit and set the OUTPUT controls in a way that identical
levels are shown on both units. Switching on CHARISMA´s chan-
nels will give the aural impression that the processed signal is
louder than the unprocessed. If this effect is not impressive
enough, turn the DRIVE control a little further clockwise.
After setting the DRIVE control, start to vary the CHARISMA
control. This control varies the tube sound from HARD to SOFT.
In the SOFT position the processing curve looks similar to that
of a soft-knee limiter curve. The tube processing comes in softly
with a gently rounded curve, whereas in the HARD position the
programme material is treated more dramatic. This can be
compared with the processing curve of a hard-knee limiter.
A specific CHARISMA control setting may make it necessary to
readjust the DRIVE control. If you use a SOFT setting, the proces-
The Charisma-
control
Getting started
Set-up positions
Normal processing

9
Avoiding clipping when
recording digital.
Capturing the sound of
analogue for digitally
recorded drums.
Controlling the kick of the
bass drum and the ounch of
the snare.
Improving drum room
sound.
Making acoustic guitars and
electronics basses stand out
in busy mix.
Giving extra charisma to
vocals. Improving intelligibi-
lity.
Making a tube mic out of
your standard mic.
Creating heavily distorted ´in
your face´ sounds.
Tip offs
sing starts earlier, which means you can hear the effect already
at lower DRIVE levels in comparison to HARD settings. A medium
DRIVE level may already be sufficient to drive the tubes hard
enough.
In a HARD setting you will find yourself using higher DRIVE
levels, because the processing starts later than in a SOFT setting,
but it is very efficient immediately.
When recording to a digital media it is essential to avoid clip-
ping and the tube limiting is a great tool for this purpose. Critical
peaks are smoothed resulting in increased subjective loudness
while controlling the electrical level.
Traditionally, drums have been recorded to analogue tape –
even digital drum tracks are frequently copied to analogue tape
purely to capture the sound of tape saturation. With CHARISMA,
you can achieve the same analogue warmth, punch and power
without the inconvenience or noise of an analogue tape
machine. Even sampled drums really start to sound much more
like real drums.
Choose an extreme HARD setting (fully clockwise) for kick
drums or snares. You effectively prevent clips on your digital
recorder while you also have control about the kick of the bass
drum or the ounch of the snare. It is interesting to use CHARISMA
on room tracks when recording live drums. Choose a SOFT
setting with a high DRIVE level. This will open up your drum
room.
Acoustic guitars benefit from the CHARISMA effect with
improved transparency and clarity, yet the recorded instrument
retains the same liveliness and character as the original.
Electronic basses become better focused, or you can add just a
hint of deliberate distortion to help make them stand out in a
busy mix.
When recording vocals, the CHARISMA allows the voice to stand
out in the mix without increasing the actual level – any good
studio mic effectively becomes a valve mic. Intelligibility is
greatly enhanced by the tube harmonics, and you can even make
a clean voice sound smoky by driving the CHARISMA a little harder.
That´s something a tube mic doesn´t allow you to do.
It is often a good trick to use a compressor before the
CHARISMA when processing vocals. This will help you finding an
appropriate DRIVE level.
Producers of dancefloor/trance/ambient music will find
CHARISMA a remarkable creative tool for distorting bass drums,
snare- and lead sounds absolutely free from noise and hum – a
clear advantage over the guitar-preamps. Even original
303/808 bass and drum sounds gain additional kick and
authority. CHARISMA lets you produce really ´in your face´
sounds.

10
Power Supply
Creating rough sounds,
Creating new harmonics,
Processing synth sounds.
CHARISMA can be used with extreme settings: For example, set
the DRIVE maximum and create richest Hammond organ sound.
Give clean guitars more bite or even softly distort them, or
make vocals rough and dirty.
You can run your favorite samples and synth sounds through
CHARISMA and give them the final edge. Give yor TB 303 clone
the bite of the original 303. By widening the harmonical spec-
trum you have unlimited possibilities to boost and refreshen
synth sounds or create new ones.
Special care has gone into the design of the power supply of
the CHARISMA. The power supply is the heart of an electronic
system: The better it is, the better the whole system works and
–in an audio system – the better it sounds.
This power supply is based around a custom made 15VA
toroidal transformer and is designed to minimize induced hum
and noise due to the non existence of an air-gap.
The primary voltage may be selected between 230 V/50 Hz
and 115 V/60 Hz by means of a recessed slide switch on the
rear panel.
The rear panel ground-lift switch may be used where ground
loops are causing hum problems. When the GND LIFT switch is
set to off, the circuit ground is no longer connected to the chassis
ground. The power cord connector is a 3-wire, U-ground, stan-
dard IEC mains connector for a detachable power cord
(enclosed). Transformer, power cord and mains connector have
VDE, UL and CSA approvals. The fuse has a value of 315 mA.
On the secondary side of the power supply, an RC combina-
tion is used to filter out noise and hum voltages from the mains
side. Both half-waves are smoothed with 2200 µF capacitors in
the positive and negative voltage path. Both pathes use preci-
sion voltage regulators, as deviations of only a few millivolts
can result in audible changes such as a diffuse sound pattern.
Extreme Processing
Tip offs