Crest Audio SmarTube ST2 User manual

SERIES
Features Description
• Two separate full channel strips in a single rack-space unit
• Front panel mic/line jacks
• Separate insert send and return jacks
• Solid-state, tube-sound processor (SmarTube™)
• Expandability – daisy-chaining of multiple units
• Superior coating and finishing technology
• Affordability
• Multicolor 10-segment LED meters
• Full parametric EQ (low-mid and high-mid)
• Low and high shelving controls
• 24dB/oct LCF (low cut filter)
• "Sizzle" control
• Balanced and unbalanced I/O
Applications
•Broadcasting
•Installations
•Live sound
•Recording
•Anywhere a high quality mic preamp is needed
The ST2 is a two-channel, single-rack-space voice proces-
sor/channel strip. Each of the two channels consists of four
functional sections: microphone and line preamplifier, 4-
band parametric equalizer, output level/pan/meter/sum, and
SmarTube tube-sound processor. A variety of inputs, out-
puts and insertion points allow each of these sections to be
used separately or together. With its versatility, comprehen-
sive features set and expandability, the ST2 is intended to be
used for both recording and live performance applications.
Each of the two channels provides an XLR low-impedance
microphone input and a high-impedance 1/4" line/instru-
ment (DI) input with jacks conveniently located on the front
panel and duplicated on the rear panel. Both inputs have
separate gain controls. The balanced XLR mic input has
a –20dB Pad, Phase-reverse (polarity), a +48V phantom
power switch with LED, and a switchable, fourth-order
high-pass filter. An insert unbalanced I/O with separate
1/4" send and return jacks is provided on the back panel.
Equalization consists of a low and high shelving section
and two fully adjustable Low-Mid and High-Mid parametric
filters. There is a level, pan and SmarTube blend control
with bicolor LED, mono/stereo, sizzle and mute (with LED)
switches and post-level, pre-pan unbalanced direct output.
Metering comprises of a 10-segment multiple color LED
bar graph array that indicates the level on the direct output
and a separate signal-presence LED.
The two channels can also be assigned independently to
either the A/B stereo bus or only A or B bus via the
stereo/mono switch. In stereo position the channel 1 signal is
panned between the A and B bus. In mono position the chan-
nel 1 signal is sent only to the A bus, bypassing the Pan pot.
In stereo position the channel 2 signal is panned between the
A and B bus. In Mono position the channel 2 signal is sent
only to the B bus, bypassing the pan pot. unbalanced (0dBu-
1/4") and balanced (+4dBu-XLR) outputs are provided on
each of the A and B summing buses. A pair of additional, bal-
anced (+4dBu-1/4") I/Os enable the expansion capabilities of
the ST2. Several units can be daisy-chained, each next
becoming a master for the preceding ones.
The ST2 has a built-in power supply and the line connec-
tion is through an IEC connector on the back panel. A mas-
ter power switch with on/off LED indicator is located on the
right side of the front panel.
ST2TM Dual Ch. Mic
SmarTubeTM Preamp

Specifications ST2TM Dual Channel SmarTubeTM Mic Preamp
Crest Audio Inc.
16-00 Pollitt Dr. Fair Lawn, NJ 07410 USA
TEL: [phone] FAX: [phone]
www.crestaudio.com
*A4500015*
Crest Audio reserves the right to make improvements in manufacturing or design which may affect specifications.
9/4/01
v.1.5
Architects’ & Engineers’ Specifications:
Each of the two input channels 1 and 2 has an
XLR low impedance (2.2k Ohm) microphone
and a high impedance (200k Ohm) 1/4"
Line/Instrument(DI) inputs with jacks conve-
niently located on the front panel and duplicat-
ed on the rear panel. Both inputs have sepa-
rate gain controls with wide gain range
(Microphone: 0-60dB and Line: OFF to +10
dB). The mic input has a –20 dB pad switch; a
phase-reverse (polarity) switch; a +48V
Phantom power switch with LED; and a switch-
able, fourth-order high-pass filter with 24
dB/oct slop and 75 Hz corner frequency. An
insert unbalanced I/O with separate 1/4" send
and return jacks is provided on the back panel.
Equalization consists of a shelving low and
high section and two fully adjustable paramet-
ric filters. The low and high shelving is a
Baxandall type EQ with 80 Hz and 12 kHz cor-
ner frequencies. The low-mid parametric sec-
tion is a symmetrical, bell-shaped type and
provides a +/-15 dB boost/cut within the fre-
quency range 100 Hz ~ 3 kHz and bandwidth
range 2 ~ 1/5 octaves. The high-mid EQ sec-
tions has the identical characteristics with the
exception of the frequency range, which in this
case is 500 Hz ~ 15kHz. The Level control
ranges from OFF to +6dB. The pan control
directs the signal between A and B summing
bus when the stereo/mono switch is disen-
gaged. The SmarTube™control blends the sig-
nal between the main channel with the signal
after the tube-sound processor circuit and
ranges from clean to all-tube sound. The pur-
pose of the tube-sound circuit is to replicate
the characteristics and the sound quality of a
microphone tube amplifier, by introducing the
harmonics structure typical for a tube stage.
This circuit utilizes solid-state technology. A
bicolor LED is provided to indicate that the
tube-sound processor is active (green) or over-
driven (red) to maintain a balanced sound
quality. The Sizzle switch introduces a slight (3
~ 4 dB), broadband boost within the high fre-
quency range. The mute (red LED) switch
mutes all channel outputs and the meter. The
output channel signal is monitored via 10-seg-
ment, multiple color LED array with –21 dB to
clip (2 dB before clipping) range. A separate,
green signal LED indicates the presence of a
signal (-20 dBu) through the channel, regard-
less of the mute switch position.
Gain:
Equalization:
Low Shelf:
Low-Mid Parametric:
High-Mid Parametric:
High Shelf:
Low Cut Filter (Mic input only):
THD:
Frequency Response:
Hum & Noise:
LED Indicators:
Phantom Power:
Power Requirements:
Dimensions (H x W x D):
Weight:
Mic: 0dB to +60dB (low Z)
Line: OFF to +12dB (high Z)
Level: OFF to +6dB
\Boost/Cut: +/-15dB, Frequency: 80Hz
Boost/Cut: +/-15dB, Frequency: 100Hz to 3,000Hz, Bandwidth: 2 to 1/5 octaves
Boost/Cut: +/-15dB, Frequency: 500Hz to 15,000Hz, Bandwidth: 2 to 1/5 octaves
Boost/Cut: +/-15dB, Frequency: 12,500Hz
Frequency: 75Hz, Slope: 24dB/octave
<0.005%@1kHz (22Hz –80kHz BW)
+0dB/-1dB, 20Hz –20kHz (Mic @ max gain, EQ flat)
(22Hz –22kHz BW) EIN (Mic 150 Ohm): -129dBu
Direct Output: -97dB, all controls OFF, -86dB, nominal settings, gains minimum
Switch closure indicators, 10-segment multicolor LED ladder indicates output level
(0dB = 0dBu unbalanced outputs and =+4dBu @ XLR balanced outputs)
+48V (Microphone XLR Inputs only)
Dom: 120VAC 60 Hz 15W, Exp: 230VAC 50/60 Hz 15W
1.75" x 19" x 10.5"
(4.44 cm x 48.26 cm x 26.7 cm)
8.2 lbs. (3.7 kg)