a designs ventura se front

Ventura SE Mic/Instrument Preamp and EQ


The Ventura SE is a world-class mic preamp, instrument preamp, and 3-band EQ

all housed in a single 1U rack space


Hand-built in the USA, the Ventura SE features three discrete inputs – microphone, instrument and EQ/insert – which may be used together or independently. The product is also equipped with a highly musical three-band parametric EQ and high/low filters, as well as three discrete outputs for each section.

The heart of the Ventura SE is its C12X discrete transistor operational amplifier designed by Carl Johnson that operates on ±30 VDC rails. The C12X is a high-gain, fast-slew, stable audio block with virtually no DC offset over the audio spectrum and is capable of driving a 50 ohm load at 50 Hz with very little current draw. It is used in the microphone preamp, instrument input amp and main output/EQ output stages.


Microphone Preamp

The Ventura microphone preamp features a balanced single-stage discrete opamp, transformer coupled design.  Running at normal levels, the discrete analog preamp sounds very clear and transparent with extended bass.  When pushed, the preamp will saturate providing more color while still retaining clarity.  This section feeds the EQ and preamp outputs simultaneously and includes phase reverse, -20 dB pad, +48V phantom power with LED indicator and gain control knob.  With the front panel “source switch” set to mic, the signal is fed to both EQ/Main and transformer outputs simultaneously.  Having two separate outputs at one time can be useful for feeding signal to FOH and/or external effects, power amps, etc.


3-Band Parametric EQ

Styled after the Quad Eight EQ, the Ventura SE 3-band parametric EQ features 33 frequencies.  The 3 bands have overlapping ranges from 50Hz to 15 KHz.  Both frequency and boost/cut controls are stepped for precise settings and easy recall.  Each band has its own 3 position Q switch for Sharp, Wide, and Narrow settings.  The high and low bands are peak/dip type with switches to change them to a shelf type.  The shelving switches disable the Q feature on high/low bands only.

The EQ Input/Insert Return jack provides a direct balanced input to the EQ, bypassing the mic and instrument preamps.  This allows for use of external FX to be directly added to the signal through the EQ for added flexibility.


Instrument Input Preamp

The Ventura SE can also eliminate the need for a Direct Box/DI with its high-impedance unbalanced preamplifier designed for guitar/bass and keyboards.  The instrument preamp section uses a single-stage discrete opamp, independent from the mic pre.  The front panel features a 1/4″ TS Switchcraft input jack with gain control and Hi/Low gain switch at the rear.  With the source switch set to instrument the input is fed to both the EQ/Main out and Multi out providing 2 simultaneous outputs.  The Ventura SE also features a separate unbalanced instrument direct output on the rear panel. In use, this output breaks signal feed to the multi and EQ output sections allowing the instrument section to be truly independent.


High and Low Pass Filters

The high and low pass filters are a fixed second order 12dB per octave type with the knees at 9 kHz and 150 Hz. Both filter switches work whether the EQ switch is in or out and are post the EQ which affects the Main/EQ Output only.


Images (click to expand)


Single 1U Rack Space Steel Chassis
Cinemag Output Transformers
Jensen Input Transformer
Three Specially Designed Discrete Operational Amplifier
Solid State Design
Neutrik XLR Input and Output Connectors
NEW - Individual Input and Output for Each Section: Mic, Instrument and EQ
Separate Gain Controls for Mic and Instrument Input Sections
NEW - Output Gain Switch for the Instrument Section
-20dB Mic Pad Switch
+48Vdc Phantom Mic Power
Phase Switch for the Mic
Blue LED Power Indicator
Toroidal Power Transformer
Discrete Mic Preamplifier with 72dB of Gain
Discrete Instrument Input Preamplifier
Red LED Phantom Indicator
True Three Band Parametric Equalizer
2 Filters - High Pass / Low Pass
TRS Balanced Insert Return / EQ Input
Silver Contact High Durability Toggle Switches
Input Impedances: Microphone - 1.4k ohms; Instrument - 20Meg ohms nominal; Insert / EQ Input - 15K ohm
Gain Input Ranges: Microphone -62dbv to +30dbv; Instrument - 70db; Insert / EQ - 0dbv to +26dbv
Noise (EIN): -120dbm
Phantom Power: +48VDC
Balanced XLR Outputs: 600 ohms nominal
Distortion: 0.01%
Power Requirements: 120 / 230 VAC - 23 Watts
Dimensions: 19" x 1.75" x 10"
Weight: 14lbs. - 16.5lbs shipping weight