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1、RadioFans.CN 收音机爱 好者资料库 Home | R.47 | Audio Demo | Technical & Historical | News | Contact | Terms We are not accepting orders for the R.47 MkII at this time Revolution Recording Equipment R.47 MkII The Classic British Vacuum-Tube Microphone Amplifier The Revolution Recording Equipment Microphone Am
2、plifier Type: R.47 is a single channel microphone and line valve amplifier based on a true classic. The Class A circuitry utilizes a pentode to triode configuration that provides up to 46dB of effective gain between an incoming signal and the balanced line level output. While derived from a vintage
3、design, many refinements have been employed which take advantage of contemporary electronic technology. The signal-to-noise ratio is extremely good, and the equivalent hum and noise can be taken as equal to or better than 130 dBu referred to the input when the amplifier is set for maximum gain. The
4、unit is capable of an output level of +23 dBu on overload peaks before severe audible distortion becomes apparent. The vacuum-tube circuitry adds warmth and colour to the bass and the low-mid range of the frequency spectrum, resulting in a distinct richness to vocals, drums and bass. The frequency r
5、esponse is relatively flat through the upper end of the audio spectrum, with a wonderfully ethereal and open high end not typically associated with valve designs. The amplifier circuitry has a very fast response that captures every delicate dynamic nuance of vocals and instrument transients. What tr
6、uly distinguishes the R.47 is the way signals acquire a clarity and presence that floats them to the front of the mix, this characteristic is consistent through a wide range of sources, from inexpensive dynamic microphones to classic valve types. John Hinson, acclaimed for his achievements with Univ
7、ersal Audio, is the engineer behind the Revolution equipment design and development. For this very special endeavor, John embraced two important principles in his design philosophy: simplicity and uncompromising standards. The signal path requires only the essentials, especially for the active ampli
8、fication circuitry. The audio signal path uses only the highest quality commercial components, and custom transformers that meet rigorous standards. The painted steel chassis and engraved front panel complement the sturdy selectors and switches, and the solid construction is built to service studios
9、 for decades to come. Partial List Of Users Abbey Road Studios Brian Kehew (Recording The Beatles) East West Studios (Formerly Cello) Billy Corgan (Smashing Pumpkins) Marc Streitenfeld (Film Composer) Steve Kempster (Film Score Engineer/Mixer) 05/03/2009Revolution Recording Equipment R.4 RadioFans.C
10、N 收音机爱 好者资料库 Features Hand assembled using only the finest components (Hovland, Caddock, Mills) Selected New Old Stock (NOS) vacuum tubes Custom made gold plated switches (ELMA) Massive, custom-wound input and output transformers Fully regulated, over-designed H.T. & L.T. power supplies Switched gai
11、n and attenuator controls for repeatability Cardas and Kimber chassis wiring No silk-screen! - front panels are engraved and painted Thick, welded steel chassis for extreme durability Specifications Source Impedance: 200ohms Input Loading Impedance: 2K ohms (attenuator off) Maximum Input Level 20 Hz
12、: +7dBu (attenuator & pad off) Minimum Gain: -4dB Maximum Gain: +46dB Frequency Response: +/- 0.25dB 20Hz to 20kHz (high end -3dB point 48 kHz) Signal to Noise Ratio: 80dB Equivalent Input Noise: -130dB Internal Output Impedance: 50 ohms Suggested Minimum Load: 450 ohms Maximum Output Level: +23 dBu
13、 Power Requirements: 120 or 240 VAC, 50/60 Hz Dimensions: 19 W, 3.5 H, 7 D Weight: 19lbs Details Standard Single Channel R.47 MSRP: $3000.00 USD Custom Matched R.47 Units: Please Inquire The R.47 Microphone Amplifier is available only by special order at this time Delivery Time: Please Inquire R.47
14、SIGNAL DIAGRAM 05/03/2009Revolution Recording Equipment R.4 RadioFans.CN 收音机爱 好者资料库 MIC. INPUTBalanced Microphone Input. Pin 2 + with switchable Phantom Power. 200 ohm Impedance. MIC. ATTEN.Eleven Position Input Attenuator Network (Pad) with a range from -20dB to 0dB in 2dB increments. The Microphon
15、e Attenuator is a Pad network that will change the impedance of the input load. Subsequently, the increased impedance will change the character of the microphone response changing the colour of the signal. 10dB PADOn/Off Switch for fixed 10 dB input pad. BASS LIFTA unique passive filter circuit to c
16、ompensate for a loss in low frequencies when using microphones with a figure-of-eight pick-up pattern. AMPLIFIERThe amplifier consists of two valve stages, resistance-capacitance coupled with two loops of negative feedback. In the block diagram, the input and output transformers are nested in the am
17、plifier section. GAIN CONTROLS Four Position Rotary Selector to control amplifier gain (frequency compensated) fixed at 34dB, 40dB, and 46dB. The optimal setting for the Gain control is 40dB. Not only does this conform to the original specifications, but it has the best colour for general purposes f
18、rom vocal to instrument recording. POLARITYThe Polarity reverse switch reverses the output phase from Pin 2 + to Pin 3 + OUTPUTFloating Balanced Line Level output. Pin 2 + R.47 CONTROLS 1. MIC. ATTEN. (dB)Eleven Position Input Attenuator Network (Pad) with a range from -20dB to 0dB in 2dB increments
19、. 2. 10dB PADOn/Off Switch for fixed 10 dB input pad. 3. GAINFour Position Rotary Selector to control amplifier gain (frequency compensated) fixed at 34dB, 40dB, and 46dB. 4. POLARITYOn/Off Switch for polarity (phase) reversal of the output signal. 5. +48VOn/Off Switch for supplying phantom power (4
20、8V) to non-valve condenser microphones. 6. BASS LIFTOn/Off Switch for a unique passive filter circuit to compensate for a loss in low frequencies when using microphones with a figure of 8 pick-up pattern. 7. GAIN TRIMLocked fine gain adjustment control for balancing gains of matched pairs of R.47 am
21、plifiers. The range of adjustment depends on the setting of the main gain control (# 3 above) but is approx. +/- 1 dB. 05/03/2009Revolution Recording Equipment R.4 8. STUDIO REGISTRATION Custom units require component and tube matching. These are issued with the Studio Name and Serial Number engraved on the front panel. 9. POWEROn/Off switch for main AC power. 05/03/2009Revolution Recording Equipment R.4 05/03/2009 19:22:55 05/03/2009 19:22:32
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