Origin Effects Cali76 User manual

Key Features:
• 100% Class-A discrete signal path
• Ultra-fast “FET” response
• Attack & Release presets
• Studio-grade “discrete” preamplifier
• Rugged VU-style meter
• Low-noise electronics
• Optimised for guitar but also great for
processing recorded instruments
• Selectable True, or Buffered, Bypass
• 50 hours life from single 9V / PP3 cell
• Optional external power (9-18V DC)
• Traditional Through-Hole PCB
The Cali76 is a premium-quality, 1960s-
style FET compressor, inspired by the
legendary Urei 1176. The idea behind this
design was to bring the sonic properties of
this revered studio-classic into the scope of
the average guitar-geek…
The topology of the design was kept true to
the original, whilst the actual circuitry was
carefully condensed. In this way it has been
possible to retain the much-loved dynamic-
response of the original, whilst at the same
time permitting a smaller, more stage-
friendly format!
Excluding the VU meter, the circuitry is
wholly transistor-based (otherwise known
as "discrete"). Well designed transistor-
circuits, in contrast to IC-based designs,
generate fewer harsh distortion artefacts.
In addition, subtle harmonics are created
which can positively-enhance tone.
Origin have also included a studio-grade
1960s-style discrete preamp, to work as an
interface between your guitar and the
compressor. The preamp provides gain and
also creates the optimum conditions for
signal transfer.
The pedal can be powered by a 9V battery
or from a 9V to 18V DC power supply. A
higher voltage supply will increase the
dynamic-range/headroom of the unit…
The Cali76 is a great performance tool, but
is by by no means limited to this task.
Recording guitarists will find the unit
highly useful for post-processing recorded
drums, bass and vocals. The Cali76 will
tame rogue dynamics and liven up flat-
sounding mixes... Best of all it will impart
a strong analogue footprint on otherwise
sterile, digitally-recorded tracks.
Example Settings for Electric Guitar
"FET" BASED STUDIO-STYLE LIMITING AMPLIFIER
INSTRUCTIONS / INFORMATION
Figure 1: Useful Settings: (a) subtle compression; (b) percussive compression; (c)
spongy compression (try "popping" strings when soloing).

Input/Comp Control
The Cali76 features a very nice studio-grade input
preamplifier. This works as an interface between the guitar
and the compressor sections. In exactly the same way a
studio-engineer will first amplify a dry guitar signal before
applying additional processing.
The "INPUT/COMP" control allows the user to vary the gain of
this preamplifier. Turning this control clockwise increases the
overall gain of the pedal. This also increases the amount of
compression. The guitar will become increasingly more touch-
sensitive. Too much gain and the preamplifier will clip and
distort.
Compression is greatly reduced at lower gain settings as much
of the signal entering the compressor section falls below the
compressor's internal threshold. Signal level must exceed this
threshold in order to initiate gain-reduction. In this scenario
only the signal-peaks are compressed.
Output
The Output control simply varies the level of signal present at
the pedal's output jack. This can be set in order to keep the
overall effected-level close to the, dry (bypass) signal.
Alternatively, the level can be increased to help project a
guitar solo.
Attack & Release
Attack & Release controls are all too often misunderstood,
which is unfortunate as they are instrumental in achieving a
usable sound. In most cases Attack & Release parameters
should be adjusted to optimise the compressor's dynamic
response to that of a particular instrument. However, they can
also be adjusted to create strong dynamic effects.
The Attack control determines the time taken for the
compressor to react to the presence of a signal, i.e. the delay
from the instant when you play the note, to the moment the
compressor actually reduces the gain. The longer the Attack-
time/delay, the more pronounced the beginning of each note
will sound.
In the context of the guitar - you may make the following
observations when adjusting Attack settings:
Increasing Attack-time highlights the percussive "snap" of
strongly picked notes.
Reducing Attack-time may impart a "spongy" feel to the
character of the compressor - especially when "digging-in" to
single notes!
Reducing the Attack-time to a very short time will result in
undesirable distortion being generated - this will be heard to a
greater extent when playing bass notes.
The Release control determines the duration of any gain
reduction. This would be measured from the time that
compression is triggered to the point that the compressor has
returned to its idle state. For maximum effect when processing
guitar, the Release must be set so that the compressor
responds fully to every note played. If so, the release time
must be short enough for the compressor to fully recover in the
short time between one note ending and the next note
beginning.
Ratio
The Ratio control allows the user to adjust the amount of gain
reduction applied for any given increase in guitar signal. At
the lowest ratio-setting, doubling the input signal (an increase
of 100%) will result in the output increasing by 19%. At the
highest ratio-setting, the output would rise by only 3.5%, for
the same increase in input signal. The latter case represents
"Limiting".
As was the case in the Urei 1176, changing the ratio setting
also varies the threshold level of the unit. This helps to keep
the output at a consistent level, regardless of settings.
Example Settings
Figure 1 presents some useful starting points, intended for use
with guitar. Figure 5 consists of some more examples for use
in processing various recorded instruments.
Bypass Mode (Internal Selection)
The bypass mode can be selected internally by changing the
positions of four internal jumper-connectors.
"True-Bypass" can be obtained with all four jumpers in the
lower-position.
A low impedance, or buffered-bypass, mode can be selected by
moving all four jumpers to the upper-position. In this mode,
the pedal will ensure that signal integrety is preserved even
when driving long cable runs.
Jumpers can be simply pulled away and pushed back into
place. Spare jumpers can be easily obtained if required.
Figure 2: J4, J5, J6, J7: Bypass Jumper-Connectors.
Figure 3: Changing the jumper position on J4.

Input Sensitivity / Jumpers
The latest version of the Cali76 features a set of jumpers that
give the user control over the sensitivity of the unit.
Should you prefer to have the input/gain control set very low,
it could be worth experimenting with the jumper arrangement
shown in figure 4. This will almost certainly help users to
obtain more rotational resolution in a pro-audio set-up, where
signals are relatively large.
Moving the jumper progressively right will result in more
input attenuation and less sensitivity.
Battery & External Power
The internal 9V battery will provide good-quality operation for
approximately 50 hours. After this time the user may choose
to fit a fresh battery. This can be done easily by removing the
four screws from the base of the enclosure. From here the new
battery just clips into place. Be careful not to knock any of the
components on the circuit-board.
Alternatively, an external supply can be used. A high quality
regulated supply should be chosen to avoid damage from
voltage-surges and other over-voltage conditions. The
connector should be the 2.1mm type with the centre-pin
"Wired-Negative".
For best performance, the pedal should be powered from an
18V supply. This will increase the headroom, allowing cleaner
processing of conventional guitar signals. This will also permit
the use of hotter source signals, such as active guitar pickups.
It's unnecessary to remove the battery when using an external
supply. There is no risk of damage to either the battery,
supply or pedal. However, as is the case with all battery
powered goods, old batteries are prone to leaking and so
should not be left installed for prolonged periods of time.
About the Designer
"Origin" products are currently being developed by Simon
Keats, of UK-company, Keats Audio. Simon has worked for a
number of big-name "audio" companies, on a full-time basis
and as a design consultant.
Simon can be reached by email, telephone or by post, and will
be happy to help with any enquiries.
Email: [email protected]
Telephone: [phone]
International: [phone]
Address: Simon Keats
Origin Effects
First Floor Office
Unit C6 Station Yard
Thame
Oxfordshire
OX9 3UH, UK
Simon Keats/Origin Effects is not affiliated with Urei or Universal
Audio in any way. This product draws inspiration from the Urei "1176"
compressor, but does not feature any "like-for-like" circuitry!!!
Figure 5: Useful Settings: (a) vocals - subtle compression; (b)
vocals - limiting; (c) acoustic guitar / piano; (d) bass; (e) drums
- subtle compression (famous Dr.Pepper Setting); (f) drums -
"pumping" hard compression.
Note: All source signals normalised to -10dBV.
Figure 4: Input sensitivity jumpers on Cali76TX.