962 DIGITAL VACUUM TUBE PRE-AMP OPERATORS MANUAL i
TWELVE MONTHS LIMITED WARRANTY DRAWMER ELECTRONICS LTD., (HEREIN AFTER KNOWN AS THE MANUFACTURER) WARRANTS THIS AUDIO PRODUCT TO BE FREE FROM DEFECTS AND CONFORM SUBSTANTIALLY TO THE SPECIFICATIONS OF THIS MANUAL FOR A PERIOD OF TWELVE MONTHS FROM THE ORIGINAL DATE OF PURCHASE, WHEN USED IN ACCORDANCE WITH THE SPECIFICATIONS DETAILED IN THIS MANUAL. THIS WARRANTY IS NOT TRANSFERABLE. IT APPLIES ONLY TO THE ORIGINAL PURCHASER OF THE PRODUCT.
CONTENTS SAFETY CONSIDERATIONS page 1 INTRODUCTION page 2 APPLICATIONS page 3 INSTALLATION " Audio connections " Digital connections " Power connections page page page page 4 4 5 7 CONTROL DESCRIPTIONS: " Channel Input " Limit " Microphone Pre-amplifier " Auxiliary Input " Line Input " High and Low Pass Filters " Fine Tune EQ " Enhance " Tube Drive " Stereo Mix " Digital Section D62-T/-A (where fitted) " Stereo Link operation page page page page page page page page page page page page page 8 8 8
For the USA FEDERAL COMMUNICATIONS COMMISSION RADIO FREQUENCY INTERFERENCE STATEMENT This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation.
1 1962 OPERATORS’ MANUAL DRAWMER 1962 Digital Vacuum Tube Pre-Amp SAFETY CONSIDERATIONS CAUTION - MAINS FUSE TO REDUCE THE RISK OF FIRE REPLACE THE MAINS FUSE ONLY WITH A FUSE THAT CONFORMS TO IEC 127-2. 250 VOLT WORKING, TIME DELAY TYPE AND BODY SIZE OF 20mm x 5mm. THE MAINS INPUT FUSE MUST BE RATED AT 250mA WHERE THE MAINS INPUT VOLTAGE SWITCH IS SET TO 230 VOLTS AC. AND 500mA WHERE THE MAINS INPUT VOLTAGE IS 115 VOLTS AC.
2 1962 OPERATORS’ MANUAL INTRODUCTION The 1962 is a hybrid vacuum tube/semi-conductor, dual-channel pre-amplifier which features extremely low noise operation and the option of a 24-bit digital output. Balanced microphone and line inputs are included making the 1962 a powerful and versatile tool in all areas of audio, including studio recording, live sound, location recording, postproduction, mastering and as part of a musician's rack system.
3 1962 OPERATORS’ MANUAL APPLICATIONS Standalone microphone preamplifiers are generally associated with direct-to-stereo recording or with the purist recording approach by which the traditional console is bypassed wherever possible. Though ideally suited to these applications, and to applications where instrument level signals require to be DI'd, the 1962 is much more flexible than traditional preamplifiers, because of its variable Tube Drive control and its versatile equaliser/enhancer section.
4 1962 OPERATORS’ MANUAL INSTALLATION The 1962 is designed for standard 19" rack mounting and occupies 2U (88mm) of rack space. Avoid mounting the unit directly above power amplifiers or power supplies that radiate significant amounts of heat, or in poorly ventilated or unusually warm environments. We advise that a blank space above the unit with a ventilated rack blanking panel is fitted. Fibre or plastic washers may be used to prevent the front panel becoming marked by the mounting bolts.
5 1962 OPERATORS’ MANUAL outputs of the 1962 to the patchbay. If such measures are necessary, balanced operation is recommended. Various signal cable earthing options may have to be tried to achieve the most hum-free connection. STEREO MIX IN/OUT The Stereo Mix In/Out sockets are stereo TSR jack connections which simplify connection of other 1962 units, stereo sends from a mixer, or similar line level device(s). The wiring convention is: ring, right channel, tip, left channel and sleeve ground.
6 1962 OPERATORS’ MANUAL z The LED will illuminate brightly and steadily if a reliable and compatible clock source is recognised. The LED will blink when External Clock is selected on the front panel, but no external clock is detected. ' The LED will flicker dimly if the clock signal is inadequate due to problems such as level matching or signal corruption.
7 1962 OPERATORS’ MANUAL ADAT: (Where the D62-A is fitted). This is permanently enabled and presents the digital data to the standard Alesis™ format, where the stereo signal is available on all eight tracks for the operator to choose which tracks to record. If connection is to a Alesis™ ADAT it is suggested that professionally terminated optical cables are used.
8 1962 OPERATORS’ MANUAL CONTROL DESCRIPTION The 1962 comprises two independent audio channels plus a Stereo Mix section, and both channels may be operated independently or linked for stereo operation. When used in linked mode, the control-circuitry for both channels responds to the average of the two channel settings. It helps to avoid confusion if both sets of channel controls have similar, or, as near as possible, the same settings.
1962 OPERATORS’ MANUAL 9 MICROPHONE PRE-AMPLIFIER The microphone input stage is based around an advanced, discrete component design, characterised by extremely low levels of noise and distortion. The audio performance is significantly better than what is normally achieved by the input stage of a typical, high quality recording console.
10 1962 OPERATORS’ MANUAL Gain: When depressed, provides an additional 20dB of gain to the auxiliary input. A Yellow status LED will illuminate. Bright: Switches in a 'presence' peak of around 10dB at 2KHz to simulate the voicing of a typical guitar amplifier. Because nearly all guitar amplifiers are voiced differently, it is likely that additional EQ will be required to achieve the desired sound.
1962 OPERATORS’ MANUAL 11 HIGH & LOW PASS The high and low pass filters are included to allow the user to attenuate undesirable sounds at the extremes of the audio spectrum, such as rumble, hum or hiss. They may also be used for creative applications, either on their own or in combination with conventional EQ. In order to make these filters effective in a variety of situations, they have been designed with fixed slopes and variable frequencies.
12 1962 OPERATORS’ MANUAL Low Fine Tune: Continually variable 6dB per octave shelving filter, providing up to 12dB of cut or boost. This control may be used to add 'warmth' to the signal being processed or to moderate excessive low frequency content. Mid Fine Tune: Continually variable 6dB per octave bandpass control providing up to 12dB of cut or boost. The centre frequency of 1KHz has been chosen to emphasise 'bite' or presence.
13 1962 OPERATORS’ MANUAL occur, but as the signal level falls below 0dB, low level, low frequency transients will be enhanced proportionally. High Enhance: This continually variable control applies enhancement by increasing the amount of harmonic energy already present in high-frequency, transient signals. The control should be adjusted until the LED above illuminates periodically.
14 1962 OPERATORS’ MANUAL 2) There is a greater chance of a digital overload, undoing the control and safety feature of the limiter. 3) Any digital output level will be un-calibrated, unless the control is set to the +20dB position. Clarification of this routing can be made using the block diagram at the rear of this manual. For details of how to modify these jumpers, see Configuration Jumpers on page 19.
62 OPERATORS’ MANUAL 15 DIGITAL (when D62 module is fitted) The D62 module is a very high resolution analogue to digital converter utilising proprietary Drawmer technology. It has a selection of sophisticated dither options. There is a proprietary system enabling up to 23-bit wordlength recordings to be made across three tracks of a digital multitrack where the multitrack machine is less than 24-bit resolution.
16 1962 OPERATORS’ MANUAL 1962 FRONT PANEL DIGITAL CONTROLS: Sample Rate: This switch selects 48.0KHz, 44.1KHz and EXTernal clock for synchronising to other digital devices. Any external clock input is ‘cleaned’ by the D62 PLL and output at the rear panel BNC connector marked WORD SYNC Out.
1962 OPERATORS’ MANUAL 17 Dither (cont.): REPLAY A, B, C, D: The four positions A, B, C and D (in yellow) are used for playback from a digital multitrack recorder to the AES/EBU and SPDIF outputs, 16bit or High resolution mode will be automatically selected. Which specific tracks are replayed are detailed at the bottom of the table on the following page. If high resolution tracks are replayed with any of the tracks missing audible distortion will be heard.
18 1962 OPERATORS’ MANUAL DITHER SELECTOR OPTIONS Position Dither and Noise Shaping 1 Positions the noise shaped dither to the very top of the audio spectrum at a level of +30dB above the quantise noise floor. Because the ears are very insensitive at this frequency, the noise is inaudible, resulting in a subjectively clean signal with a wide dynamic range. Adding extreme HF EQ boost at a later stage is not recommended. 2 The same frequency as 1 (above) with only +20dB of boost.
19 1962 OPERATORS’ MANUAL STEREO LINK Stereo Link: Averages the left and right channel signals to provide the same degree of gain reduction to both limiters and balance any low / high dynamic enhance. This prevents any image shifting which could occur whenever the left and right signal dynamics varied from each other by any significant degree. Stereo link is enabled when the LED is lit. If in stereo linked mode, then each processing module such as EQ, Tube Drive, etc.
20 1962 OPERATORS’ MANUAL IF A FAULT DEVELOPS For warranty service please call Drawmer Electronics Ltd. Or their nearest authorised service facility, giving full details of the difficulty. On receipt of this information, service or shipping instructions will be forwarded to you. No equipment should be returned under the warranty without prior consent from Drawmer or their authorised representative. For service claims under the warranty agreement a service Returns Authorisation (RA) number will be given.
21 1962 OPERATORS’ MANUAL TECHNICAL SPECIFICATIONS (All measurements taken at 0dBu operating level) MIC INPUT NOISE 20KΩ 150Ω to 600Ω 470KΩ -128.5dB (@ +60dB gain) MAXIMUM INPUT LEVEL OUTPUT IMPEDANCE MAXIMUM OUTPUT LEVEL ANALOG BANDWIDTH +28dBu 50Ω +22dBu (balanced) 15Hz to 22KHz -1dB INPUT IMPEDANCES LINE MIC AUX ANALOGUE DISTORTION (THD +n) ref. 1KHz Percentage Mic and Line input at unity gain 0.01% Line Input at 0dBu 0.025% Mic Input at 0dBu < 0.
22 BLOCK DIAGRAM 1962 OPERATORS’ MANUAL
