Serpent SB4001 User manual
SB4001
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SB4001 STEREO COMPRESSOR
Thank you for your purchase of the Serpent Audio SB4001. This unit is proudly 100%
designed and built in the USA. You, as an owner of a High Quality Serpent Audio piece
of gear you can expect years of great use and customer service from us and our
equipment. This is possible through our dedication to solid design, high-end
components, and research from our industry pros.
THANK YOU
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TABLE OF CONTENTS:
DESCRIPTION / OVERVIEW
3
SPECIFICATIONS
3
FRONT PANEL CONTROLS
4
INSTALLATION
7
MAINTENANCE AND
CLEANING
7
WARRA
NTY
8
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1. DESCRIPTION / OVERVIEW:
The SB4001 is a Quad VCA based compressor, and can be used for either stereo or
mono applications. The VCA is used for the gain reduction and is a very accurate and
powerful design, perfect for a number of signal types and musical applications. VCA’s
have historically been used in a large number of classic compressors. While the
SB4001 is not directly based off of any of these classic compressors the nature of the
VCA lends itself to share some of the sonic characteristics. We have taken these sonic
qualities and have done our best to improve and augment them by carefully tuning our
circuit and features to take full advantage of what can be done with these VCA’s. We
hope you enjoy it as much as we do.
2. SPECIFICATIONS:
Input: 22KHz Input Impedance, Electronically Balanced (Accepts Balanced or
Unbalanced Signals)
Output: <100 Ohm Output Impedance, Transformer-like Floating Output, Electronically
Balanced (Accepts Balanced or Unbalanced Signals)
External In: 22KHz Input Impedance, Electronically Balanced (TRS), (Accepts
Balanced or Unbalanced Signals)
Maximum Input Level: +21dbu
Maximum Output Level: +21dbu
Maximum Output Load: 600 Ohm
Gain: 24db (+/-1dbu) [-6 to +18]
Gain Reduction Element: Quad VCA
Frequency Response: (20Hz-20KHz) +/-0.11dB
THD+N: (20Hz-20KHz) Typically 0.008%
Noise Floor: -100dbu
Dynamic Range: >119db
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3. FRONT PANEL CONTROLS:
Comp In:
This is a true hardwire relay bypass.
Note: Use this to quickly and easily hear what the SB4001 is doing to your
audio. Also use this to help balance and adjust unity gain through the unit.
Threshold:
[The threshold is defined as the point in which compression takes place. The threshold
point of the SB4001 is approximately +8dbu.]
A fully adjustable rotary potentiometer, the threshold knob will lower the threshold point
as it is turned. Unlike a traditional “compress” knob, the threshold knob will induce the
least amount of compression when it is turned fully clockwise, and will increase
compression as it is turned counterclockwise (which lowers the threshold point).
Gain:
A fully adjustable rotary potentiometer, the gain knob allows a total gain range of 24dbu
(+/-1dbu), from -6db of attenuation to +18dbu of gain.
Ratio:
The Ratio is defined as the amount of compression that takes place after the signal has
crossed the threshold point. The higher the ratio, the more the signal that crosses the
threshold will be compressed. Ratios of 10:1 or higher are generally considered
“limiting”, rather than compression.
For example: With a 10:1 ratio, for every 10db of signal above the threshold, the output
will be only 1db louder.
The SB4001 has stepped ratio times of: 1.5:1, 2:1, 4:1, 6:1, 8:1, 10:1.
Note: You may find that you get a more transparent sound to the GR with higher
ratios and more density and hold from lower ratios. Experiment with the ratio
setting and adjust the threshold along with the ratio until you have the sound you
desire.
Attack:
The Attack time is defined as the amount of time the compressor takes to respond once
the signal has crossed the threshold.
The SB4001 has stepped attack times of (In Milliseconds): 0.1mS, 0.3mS, 1mS, 3mS,
5mS, 10mS, 15mS, 20mS, 25mS, 30mS, 40mS, 50mS.
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Release (Stepped):
The release time is defined as the amount of time it takes the compressor to return to
63% of the original signal level once the signal has passed above the threshold point.
-Classic Predefined stepped release times of (In Seconds): 0.3Sec, 0.6Sec, 1.2Sec.
-A1 (Classic Auto Release) – Classic Autorelease time, which results in a fast release
time on fast transients, and a slow release time on long, quiet passages.
-A2 (Alternate Auto Release) – A faster responding, more dynamic Autorelease,
unique to the SB4001.
Variable Release:
A fully adjustable rotary potentiometer, the Variable Release control is engaged by the
“Var” position on the Stepped Release switch. It allows for any release time from 0.1
Seconds to 1.2 Seconds (+/-10%).
Note: Use the variable release to dial in the speed / tempo of the song. This
allows you to dial in the perfect release of the compression to help lock in to the
groove.
Blend:
A fully adjustable rotary potentiometer, the Blend knob enables blending between the
dry (uncompressed) signal and wet (compressed) signal, allowing parallel compression
completely within the box, with zero phase shift and zero additional routing required.
Note: One of our favorite ways to use this feature is to set the Blend to 100%
Wet. Adjust the other settings on the compressor so that you can clearly hear
the style and characteristic of compression until you have the desired sound of
the gain reduction. At this point you may have too much of a good thing. Simply
turn the Wet signal down until you have blended in the desired amount of Dry
signal. Listen for overall amount of dynamics and control. You should be able to
dial in quickly and easily just the right amount for detail and density, squeeze and
sustain.
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Filters (Sidechain):
The “Filter” control affects the frequencies going to the internal sidechain (In any
compressor, the internal sidechain is what controls the compression taking place).
Please note, this control does not filter the audio frequencies themselves, but rather the
frequencies that are being compressed.
High pass: 60Hz, 90Hz, 120Hz
Note: Use the HPF to tailor the amount of low frequency triggering the sidechain
detector. The filters for instance can drastically change the kick drum on a drum
subgroup or the 2 buss. Just twist until you have the desired amount of low end
control.
“Boost” & “Slope” both induce very useful predefined eq curves onto the sidechain
material, both essentially over compressing the high end, while under compressing the
low end. “Boost” offers more mid band compression than “Slope”.
Boost: Induces a 1K high shelf boost and a gentle 60Hz roll off onto the internal
sidechain
Slope: Induces a sloped filter curve with a crossover at 1Khz on the internal
sidechain.
External “Key” Input:
The SB4001 allows the use of an external signal to trigger the compressor’s internal
sidechain, a feature not commonly found in a 500 format module. This makes for an
endless array of possibilities, limited only by one’s imagination (duck the bass guitar
when the kick drum hits! Compress the snare out of the overheads, etc).
The external signal is sent to the mono balanced front panel TRS connection, which is
engaged by the “Ext In” pushbutton switch. Some examples of usage are:
Ducking: By sending an external trigger track (i.e. kick drum or snare) the main
audio signal will only compress when the trigger track hits.
De-Essing: By sending the main audio signal to an external EQ (by use of a “Y”
splitter or other means), and then sending the eq’d signal to the “External In” TRS
connector, the SB4001 can instantly be transformed into the ultimate de-esser as well.
Stereo Mix: By branching off the Left and Right input signals to the compressor
(by use of a “Y” splitter or other means) summing these two signals through an external
means (ie via your DAW or Mixer), and then sending the summed signal to an eq and
lastly, to the “External In” TRS connector, SB4001’s compression response of a Stereo
Mix can be fully manipulated via the external eq.
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Grind:
Grind mode induces a tube style harmonic overdrive onto the content material, resulting
in asymmetrical distortion. The level of distortion is signal dependent, so higher levels
of distortion can be achieved by driving the input signal louder. Grind affects the final
output stage of the compressor, so it will affect both wet and dry signals alike, and can
be used simply for sonic color of the dry signal even if no compression is desired.
Note: Switch the Grind in and out. Listen to what it is doing to the tone of the
audio. Listen to things like the snare and kick. Grind can help add density and
glue to the tones with in a mix. Its not a subtle effect and is great for Rock and
Pop mixes. Many of our users just leave it in all the time. It is sonically like a
second compressor all together. For classical and some acoustic music, or if you
want transparent dynamic control, you may prefer to leave it out.
4. INSTALLATION:
The SB4001 is a 500 series compressor. It requires two channels in a 500 series
compatible rack. Just be sure to safely and securely seat the edge cards of the SB4001
into the edge connectors of your 500 rack.
Note: The SB4001 can also be used in a 51x rack. If you do we suggest that you
place a small piece of card board into the bottom 2 fingers of the 51x edge
connectors in to insure that you have the SB4001 in the proper alignment to be
compliant with the standard VPR alliance.
5. MAINTENANCE AND CLEANING:
Normal cleaning and maintenance practices should be followed with the SB4001 as all
of your other studio gear. The SB4001 uses high quality components, and sealed pro-
audio switches and pots, so the switches and pots do not require any regular cleaning.
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6. WARRANTY:
The SB4001 is covered under a limited warranty from manufacturer defect for a period
of 1 year from date of purchase by the original owner, subject to factory inspection.
Warranties are tracked by serial number. Warranties are non-transferrable.
Warranty does not cover loss or theft, nor does coverage extend to damage caused by
misuse, abuse, neglect, unauthorized modification or tampering, improper storage
conditions, power surges, lightening, or other natural disasters. Warranty does not
cover wear and tear items (such as pots and switches) or cosmetic wear. Shipping and
transport damages are not covered under warranty.
In the event of required maintenance within the warranty period, unit should be returned
to Serpent Audio (or authorized repair facility). Inbound freight charges are the
responsibility of the end user. Warranty does not cover return overnight or express
shipping charges.
Serpent Audio does not authorize field repairs. Any modifications/attempted repairs by
unauthorized personnel or tampering/ removal of the warranty seal or serial number
label will void the warranty. Repairs outside of the warranty period will be subject to
parts and labor charges determined at the time of repair.
Serpent Audio reserves the right to alter the hardware, software, documents, and
design of its products without notice.
Email: info@serpentaudio.com
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