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美国DWFearn VT-2话筒放大器8 B) S; z0 `* j( f7 A1 r/ r# K- Y, V
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. G: w. r: T& p2 `: W在设计VT前置放大器时,不允许在声音质量,可靠性或坚固性方面做出任何妥协。与20世纪50年代和60年代的电子管设备一样,VT前置放大器采用重型铝制机箱,采用点对点布线。选择每个真空管以获得***小的噪音和微音,以及的声音清晰度。前面板开关控制密封的金触点精密继电器,用于所有音频切换,消除了脏接触降低声音和***小化内部音频路径的可能性。每个通道中的四个A类三极管放大器部分(在两个管中)包括整个有源电路。这个令人惊讶的简单电路,以及高品质的元件和精心的设计优化,带来了VT前置放大器的声音优势。
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Features
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& e, c& f" e. v9 t! yAll vacuum-tube design
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Lo-Z input position for superior performance with transformerless mics
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& c* M) s. A* A# tPhase (polarity) reverse switch
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7 q2 |2 d8 d0 \+48 volt phantom power (completely disconnected when off)
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Custom-design Jensen input and output transformers
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2 m( r$ H. R1 f+ J, Q$ ^; r20 dB input pad (switchable)
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5 d2 R: N; p K+ ^" L& T+ K% `- wTrue VU meters (amplifier isolated)9 p; F. a/ A* i: v5 s" v0 _& y- w& [. f
4 g/ K# d6 h- h$ BAll point-to-point audio wiring. f' X/ h5 j8 }* ^7 M( l5 u
9 W' z9 X( r% I. H. dGold input and output XLR connectors
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Polypropylene and polystyrene coupling capacitors! y: n" ~7 V) X; s9 H% y; O0 ?: N
4 `) d( y# x, q) t t. x: PAll audio switching through gold-contact, sealed precision relays
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International operation on 100, 120, or 220 VAC, 50/60 Hz
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" I8 _8 p h* j! s$ `1 YCE certified, RoHS-compliant/ A6 M- g b8 {9 z) E% q
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" W" I! U- h* |1 Z4 d% FConservatively rated precision components and rugged construction for stability and long life1 P) N5 h3 m) `/ i( ~. j7 ]# r f
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Specifications
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Input 150 ohms9 z0 x" z3 F. s& l' t
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Input Load Impedance 1.5k ohms
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Minimum Input Level -65 dBm nominal' G4 U3 ]7 J- y" F* I
3 {9 p- K2 q( IMaximum Input Level @ 20 cps -30 dBm without pad, -5 dBm with 20 dB pad7 `9 X; G& ~: d1 }+ N6 n
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Gain 53 dB
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9 b: v7 M5 n: `" w( ~7 }- h3 l2 [% IFrequency Response +/-0.25 dB 20 cps to 20 kc; -3 dB @ 0.5 cps and 55 kc
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THD+Noise less than 0.25% 20 cps to 20 kc# N) c2 v# D1 W$ v7 x
1 ?- X& m3 e( v& i; {Intermodulation Distortion SMPTE less than 0.02%! _8 x$ A4 [, K
! v' ~9 P" V: F, b' _Signal to Noise Ratio 74 dB minimum
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Equivalent Input Noise -124 dBm maximum+ f. Y0 l `' m
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Output low-Z, transformer-balanced7 v5 ^0 D6 D4 i, r/ ?/ j7 W) d
! r/ U5 L* P& fMaximum Output Level +22 dBm, 20k ohm load! n( U# c6 k0 Y. m! f+ g
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Power Requirements 100, 120, or 220 VAC, 50/60 Hz( u1 s: I. {" y, Z3 n
/ \. q' Q% w: l+ K/ T3 d0 mDimensions 19” (48.26cm) W, 5.25” (13.34cm) H, 14” (35.56cm) D4 ~3 V" g/ K$ T' ^
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