Dimensions
Dimensions (H X W X D)
3.5 x 19 x 8 inches (88.9 x 482.6 x 203.2 mm)
Weight
Shipping Weight
11.0 lbs (5.0 kg)
Electrical
Mic Preamp Input Impedance
1.9 kΩ
Instrument Input Impedance
500 k Ω
Line Outputs (Preamp & Compressor/Limiter) Impedance
Balanced 30 Ω, unbalanced 15 Ω
Compressor Sidechain Insert Impedance
1 kΩ (output), 50 kΩ (input)
Vacuum Tube Grid Power Supply
+250V DC
Vacuum Tube Heater Power Supply
+12V DC
THD+N (Mic in to LIne Out)
0.25% typical at 0 dBu out, 1 kHz, 40 dB gain
THD+N (Instrument in to Line Out)
0.2% typical at 0 dBu out, 1kHz, unity gain
Operating Voltage
100 – 240 VAC, 50/60 Hz
Power Requirements
20 Watts
Audio
Frequency Response (Mic Input)
20 Hz to 50 kHz, +0/-1dB, 40 dB gain
Frequency Response (Instrument Input)
30 Hz to 70 kHz, +0/-1dB, unity gain
Preamp Function Switches/Controls: Gain Control Range
-∞ to +55 dB for Microphone Input; -∞ to +40 dB for Instrument Input
EQ Gain
(All Bands) Sweepable from –15 to +15 dB
Connectivity
Mic Preamp Connector
Female XLR Pin 2 Hot; Electronically balanced/unbalanced
Instrument Input Connector
Tip-Sleeve ¼” Jack
Input Type
(instrument) Unbalanced
Max Input
(instrument) +21dBu unbalanced
Preamp Insert Connector
Tip-Ring-Sleeve ¼”, RF filtered
Line Outputs (Preamp & Compressor/Limiter) Connector
Male XLR and Tip-Ring-Sleeve ¼” (Pin 2 and Tip hot)
Line Outputs (Preamp & Compressor/Limiter) Type
Servo-balanced/unbalanced
Line Outputs (Preamp & Compressor/Limiter) Maximum Output Level
> +21 dBm (into a 600 ohm load)
Compressor Sidechain Insert Connector
Tip-Ring-Sleeve ¼”, RF filtered
Compressor Output Level Control Range
-20 dB to +20 dB
Construction
Preamp Insert Type
Unbalanced, Tip = send, Ring = return
Compressor Sidechain Insert Type
Unbalanced, Ring = output, Tip = input
Included Items
676 Tube Microphone Preamp Channel Strip
1x
Shipping
Weight
8.1 lbs (3.7 kg)
General
Vacuum Tube Type
12AU7A / ECC82
Equivalent Noise Level
Typically > -123 dBu with a 150 Ω source load, 22 Hz to 22 kHz
Noise Floor
Mic Insert to Comp Output<-93 dBu, unity gain, EQ flat and no gain reduction
Preamp Function Switches/Controls
Instrument Input Selects between microphone XLR input and front panel ¼” instrument input
Preamp Function Switches/Controls
+48V Sends +48 VDC through 6.81 kΩ resistors to pins 2 and 3 of the microphone input
Preamp Function Switches/Controls
20dB Pad Attenuates the microphone input by 20 dB
Preamp Function Switches/Controls
Polarity Invert Reverses pins 2 and 3 of the microphone input XLR
Preamp Function Switches/Controls
80 Hz Low Cut: Enables an 80 Hz, 12 dB/octave high pass filter in the microphone and instrument signal path
Preamp Function Switches/Controls: Post Tube Attenuation
-∞ to 0 dB
Preamp Function Switches/Controls: Peak Indicator
Illuminates RED when the Preamp is within 3 dB of clipping
EQ Low Frequency
100 Hz, Low-pass shelving filter
EQ High Frequency
10 kHz, High-pass shelving filter
EQ Mid Frequency
Sweepable from 100 Hz to 8 kHz
EQ Function Switches/Controls: Narrow
Selects the “Q” of the MID Frequency EQ. “OUT” position Q = 0.9; “IN” position Q = 2.9
Compressor Threshold Range
-40 dBu to +20 dBu
Compressor Threshold Characteristic
Selectable OverEasy™ or Hard Knee
Compressor Ratio Variable
1:1 to ∞:1; 60 dB maximum Compression
Compressor Attack/Release Modes
Selectable Manual or Auto
Compressor Manual Attack Time
Scalable program-dependent; Typically 400 dB/msec to 1 dB/msec
Compressor Manual Release Time
Scalable program-dependent; Typically 4000 dB/sec to 10 dB/sec
Compressor Auto Attack Time
Program-dependent, typically 15 ms for 10 dB, 5 ms for 20 dB, 3 ms for 30 dB
Compressor Auto Release Time
Program-dependent, typically 120 dB/sec
Compressor Peak Indicator
Illuminates RED when the Compressor/Limiter is within 3 dB of clipping
Limiter Type
dbx PeakPlus™
Limiter Threshold Range
-4 dBu to + 22 dBu (off)
Limiter Ratio
∞:1
Limiter Attack and Release
Program-dependent
Power Supply
Universal switch-mode
Fuse
T2.5AL 250V
Turn-On Time
Approximately 2 seconds
Audio Performance
CMRR
>85 dB from 20 Hz to 3 kHz, >70 dB from 3 kHz to 20 kHz
