969 VACUUM TUBE COMPRESSOR OPERATORS MANUAL CONTENTS SAFETY CONSIDERATIONS page 1 INTRODUCTION page 2 APPLICATIONS page 2 INSTALLATION page 3 CONTROL DESCRIPTIONS: " Compressor " Microphone Pre-amplifier " Auxiliary Input page page page page QUICK SET-UP page 8 IF A FAULT DEVELOPS page 9 CONTACTING DRAWMER page 9 TECHNICAL SPECIFICATION page 10 BLOCK DIAGRAM page 11 i 5 5 7 7
COPYRIGHT This manual is copyrighted © 2008 by Drawmer Electronics, Ltd. With all rights reserved. Under copyright laws, this manual may not be duplicated in whole or in part without the written consent of Drawmer. ONE YEAR LIMITED WARRANTY Drawmer Electronics Ltd., warrants the Drawmer 1969 audio processor to conform substantially to the specifications of this manual for a period of one year from the original date of purchase when used in accordance with the specifications detailed in this manual.
1969 OPERATORS’ MANUAL 1 DRAWMER 1969 Dual Vacuum Tube Compressor 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 WITH A 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. THE REAR PANEL H.T.
2 1969 OPERATORS’ MANUAL INTRODUCTION The 1969 is a hybrid vacuum tube/semi-conductor, dual-channel compressor which has numerous applications in studio recording, live sound, location recording, postproduction and as part of a musician's rack system. The microphone input stages feature extremely low noise, balanced input circuitry with additional tube amplification, enabling modern microphones to take on the characteristics of older tube models.
1969 OPERATORS’ MANUAL 3 INSTALLATION The 1969 is designed for standard 19" rack mounting and occupies 2U of rack space. Avoid mounting the unit directly above power amplifiers or power supplies that radiate significant amounts of heat and always connect the mains earth to the unit. Fibre or plastic washers may be used to prevent the front panel becoming marked by the mounting bolts.
4 1969 OPERATORS’ MANUAL POWER CONNECTION The unit will have been supplied with a power cable suitable for domestic power outlets in your country. For your own safety it is important that you use this cable. The unit should always be connected to the mains supply earth using this cable. If for some reason the unit is to be used at a mains input operating voltage which is different to that as supplied, the following procedure must be carried out.
1969 OPERATORS’ MANUAL 5 CONTROL DESCRIPTION AND OPERATION With the exception of the Aux preamp section, both channels of the 1969 are identical and may be used independently or linked for stereo operation. In both the linked modes, only Channel 1 compressor controls are functional and serve as the stereo master. In Stereo Link mode, both channels track together to avoid the inevitable image shifting that would occur if the two channels of a stereo signal were treated independently.
6 1969 OPERATORS’ MANUAL Attack: Six switchable Attack settings are provided giving various settings. The actual attack time is further modified by the release setting chosen. Attack Times: 1 2 3 4 5 6 Release: There are three fixed Release times and a further three which are programme dependent.
1969 OPERATORS’ MANUAL 7 Stereo Link: This makes Channel 1 controls the stereo master and disables the compressor stage of channel 2 when the unit is used for processing a stereo signal. Since the same gain reduction is applied to both audio channels no image shifting can occur. Big Link: Makes the compressor side chain less sensitive to low bass frequencies, so reducing the ducking effect caused by bass energy and effectively boosting the bass output.
8 1969 OPERATORS’ MANUAL Bass EQ: Passive equaliser control, which can be set to provide up to 15dB of bass boost at 40Hz. Treble EQ: Passive equaliser control, which can be set to provide up to 18dB of treble boost at 16kHz. Gain: Provides up to 30dB of gain at the Low Gain switch setting or 40dB at the High Gain setting. Low/High: Sensitivity selector switch. Adds 10dB of gain in the High position.
1969 OPERATORS’ MANUAL 9 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.
10 1969 OPERATORS’ MANUAL TECHNICAL SPECIFICATIONS (All measurements taken at +4dBu operating level) INPUT IMPEDANCES LINE MIC AUX 20KÙ 150Ù to 600Ù 2M2Ù MAXIMUM INPUT LEVEL +20dBu OUTPUT IMPEDANCE 50 Ù MAXIMUM OUTPUT LEVEL +22dBm (balanced) BANDWIDTH <10Hz to 22KHz -1dB UNITY GAIN NOISE BYPASS LINE MIC (E.I.N) CROSSTALK (All Channels) !95dB !85dB !134.5dB shorted !130.5dB @ 150Ù !129.8dB @ 200Ù Better than 80dB DISTORTION (THD & Noise) 1KHz Line Input with BYPASS selected < 0.
1969 OPERATORS’ MANUAL 11 BLOCK DIAGRAM