The Avalon VT-737SP features a combination of TUBE preamplifiers, opto-compressor, sweep equalizer, output level and VU metering in a 2U space.
The VT-737SP has three input selections: 1. The VT-737SP features a higher-performance microphone input transformer with +48v phantom selection. 2. Instrument DI high source input with jack located on front panel. 3. Balanced line input, discrete high-level Class A. The Class A preamplifier utilizes two cascaded, dual vacuum tube triodes configured with minimum negative feedback. A high gain switch boosts the overall gain of the preamplifier. The four high quality tubes are configured as singled ended anode coupled followers. A passive-variable high pass filter and hard-wire relay bypass completes the input signal conditioning. The phase reverse relay is available on all three inputs.
The opto-compressor features a minimum signal path design with twin Class A vacuum tube triodes for gain matching. The optical attenuator acts as a simple passive level controller. Full dynamic control from soft compression to hard- knee limiting can be achieved with threshold, ratio-compression, attack and release controls plus gain reduction selection on the large VU meter. Special spectral control including de-ess is available with the dual sweep mid EQ to side-chain switch. The EQ section can be flipped pre or post the opto-compressor via a front panel switch for alternate effects and tone shaping. Two VT-737SPs can be linked via a rear panel link cable for stereo tracking. The compressor bypass is a sealed silver relay for the most direct signal path.
SWEEP-EQUALIZER AND OUTPUT LEVEL
The VT-737SP equalizer utilizes 100% discrete, Class A-high-voltage transistors for optimum sonic performance. The high and low frequency bands provide the smooth characteristics of an all passive design, while the dual mid bands include variable frequency and switched Q-width selection. The enhanced range of the mid bands is extended into the high and low bands by the use of X10 frequency multipliers. The bypass switch incorporates a sealed silver relay for the most direct signal path. When the EQ to side chain is engaged, the high-low EQ remains in the audio path for "tone enhancement". The output level control provides a variable control of the overall signal path. The output amplifier utilizes another dual triode vacuum tube driving a 100% discrete, Class A, high-current, balanced and DC coupled low noise output amplifier.
- Circuit topology: 4 dual triode vacuum tubes (Sovtek 6922),high-voltage discrete Class A
- Gain Range Microphone: Transformer balanced 850/2500 ohm,0dB to +58dB Instrument: Unbalanced 1 meg ohm, 0dB to +30dB
- Line: Balanced Class A 20k ohms, -27dB to 28dB
- Maximum input level and connector types:Microphone26dB@25Hz, +30dB@1kHz balanced XLR Instrument+30dBunbalanced front panel jack socket
- Line +36dB balanced XLR
- Maximum output level: +30dB balanced 600 ohms, DC coupled,discrete Class A
- Output type and gain: XLR connector, output trim gain -45dBto20dB
- Noise 20kHz unweighted: -92dB
- Noise microphone EIN: -116dB, 22Hz-22kHz unweighted
- Distortion THD, IMD: 0.5%
- Frequency response -2.5dB: 10Hz-120kHz input filter included
- Frequency response -3dB: 1Hz-200kHz line in-out
- VU meter and gain reduction: High quality illuminated OVU=+4dB and gain reduction to -20dB
- High cut filter: Variable 6dB per octave 30Hz-140Hz
- Compressor type: Optical passive attenuator incorporatingtwin vacuum tubes and stereo link
- Threshold - Ratio: Threshold variable -30dB to +20dB,ratio-compression variable 1:1 to 20:1
- Attack - Release: Attack variable 2mS to 200mS, releasevariable 100mS to 5 seconds
- Equalizer type: Discrete Class A, variable active andswitched passive design
- Frequency bands (4): Treble - switched 10kHz, 15kHz, 20kHz,32kHz, ﾱ20dB range, shelf High mid - variable200Hz-28kHz and 2kHz -28kHz, ﾱ6dB range, hi-lo Q Lowmid - variable 30Hz-450Hz and 300Hz-4k5Hz, ﾱ16dB range,hi-lo Q Bass - switched 15Hz, 30Hz, 60Hz, 150Hz, ﾱ24dBrange, shelf
- AC power: Internal toroidal 100v to 240v, 50-60Hzselectable, 75 watts maximum
- Dimensions: 19 x 12 x 3.5 in (482 x 305 x 89mm)
- Weight: 22lbs. (10kg)
JZ Microphones BH1
JZ Microphones engineers' and users' opinion is that any Black Hole Series microphone, which is a fantastic vocal mic, is great on every application it is used. Unbelievable clarity and definition, smoothness and feel full transparency is the way industry professionals describe their own thoughts after using the Black Hole Series microphones to record their music.
It is very handy and compact with absolutely originally looking design. It has new original stand holder system (damper) and patented variable sputtering of diaphragm, using specially mixed alloy for coating. The Black Hole is produced with three switchable polar patterns (Omni, Cardioid and Figure of 8). Designer of Black Hole is sure that the result will agreeably surprise every user.
- Transducer type: electrostatic
- Operating principal: pressure gradient
- Diaphragms active diameter: 2 x 27 mm
- Frequency range: 20 Hz to 20 kHz
- Polar pattern: Omni / Cardioid / Figure - 8
- Output impedance: 50 ohms
- Rated load impedance: >250 ohms
- Suggested load impedance: 1000 ohms
- Sensitivity at 1000 Hz into 1000 ohms load: 18 mV/Pa
- S/N Ratio CCIR 468-3 weighted: 75,5 dB
- S/N Ratio DIN/IEC 651 A-weighted: 86,5 db-A
- Equivalent noise level DIN/IEC A-weighted: 7,5 dB-A
- Maximum SPL for 0.5% THD at 1000 ohm load: 134,5 dB
- Dynamic range of the microphone preamplifier: 127 db
- Phantom powering voltage on pins 2 & 3 of XLR: +48 V (+/-4 V
- Current consumption: 1,5 mA
- Output connector: 3-pin XLR male, gold plated contacts
- Signal polarity: positive toward pressure on a frontal diaphragm produces positive polarity voltage on XLR pin #2 relatively to pin #3
- Dimensions: 203 x 51 x 28