It has long been recognized that vacuum tubes impart a unique ‘warmth’ and ‘musicality’ to an audio signal, but many of the ‘classic’ tube equalizers fall short of the technical performance demanded in today’s digital recording age. Designed to complement the widely acclaimed Drawmer 1960 Mic Pre-Amp Vacuum Tube Compressor, the 1961 Vacuum Tube Equalizer combines low noise circuitry with no fewer than twelve active tube stages to provide two channels of exceptional equalization possessing unique ‘personality’. Rather than employ a continuously variable resistor as a means of frequency control, the 1961 utilizes the same rotary ‘step’ switching system used in vintage designs . This enables the component values for each frequency band to be optimized for uncompromising performance across the entire audio spectrum and also makes setting up more accurate, particularly when treating stereo signals.
The design of the 1961 allows the user to control the amount of ‘warmth’ by deciding how hard to drive the tubes giving a sound as ‘clean’ as the best discrete solid state designs or as ‘hot’ as the ‘hottest’ classic tube designs. The 1961 and 1960 Can be ‘interlinked’ to provide, in effect, a two channel vacuum tube mixing console, – the perfect mastering or post audio ‘sweetening’ tool.
A variable input level of -20dB to +20dB ensures compatibility with a wide range of input source material and enables the user to optimize signal level and drive the tubes ‘soft’ or ‘hot’ as required. LED bargraph displays give a clear indication of the input signal level.
High Pass Filter
A variable 12dB/Octave roll-off filter adjustable from – 15Hz to 500Hz section enables the user to remove unwanted low frequencies and sub-sonic noise.
Each channel of the 1961 has four main equalizer sections with six carefully chosen overlapping frequencies and a separate tube stage for increased harmonic clarity. Each section also includes variable band width from 0.3 Octave to 3 Octaves and +18dB of Cut and Boost. BASS frequencies (Hz) 20, 32, 50, 80, 125, 200. LO-MID frequencies (Hz) 100, 180, 250, 400, 650, 1K. HI-MID frequencies (kHz) 0.5, 0.8, 1.2, 2.0, 3.2, 5.0. TREBLE frequencies (kHz) 2.5, 4, 6,10,15, 25.
Low Pass Filter
A variable 12dB/Octave roll-off filter adjustable from 2.5kHz to 56kHz enables the user to remove high frequency interference or to band limit excessively high levels of high frequencies.
Two additional tube stages in the output section of each channel allow the user to achieve ‘soft clipping’ by adjusting the input level control whilst visually monitoring the effect upon the ‘Soft’ and ‘O/L’ (Overload) LED’s.
In addition to a master bypass switch, each of the parametric/shelving filters has its own separate bypass switch, making the 1961 very straight forward to set up. It allows instant A-B comparison and also enables the tube output stages to be used to add tube coloration without EQ simply by leaving each channel switched to ‘In’ and each individual EQ sections switched to ‘Out’. The master bypass switch for channel bypasses all the filter sections as well as the output stage vacuum tube circuitry.
Levels of -10dBu and +4dBu are selectable using a rear panel switch.
Insert point 1/4″ jack connectors on the rear panel enable direct connection to the Side chain or Insert points of the Drawmer 1960 Mic Pre-Amp/ Vacuum Tube Compressor. The 1961 and 1960, when ‘interlinked’, produce a powerful package for recording signals direct to tape; gain control, EQ & compression can be applied to mic/line level signals without having to go via a mixing console.
Inputs and outputs
The 1961 is provided with balanced inputs and outputs on XLR connections.
- Fast Reacting Stereo FET Design compressor with excellent Left/Right Tracking across the Full Range of compression and in a 1u rack mount housing
- Threshold, Ratio, Attack and Release controls and Gain Reduction Metering provide familiar and intuative control over the audio. Anyone that knows how to use a compressor can operate the 1961
- 4 character switches provide a multitude of compression flavour combinations that allow the 1961 to take on the characteristics of other compressors
- A Saturation knob allows you to dial in variable amounts of 2nd and 3rd harmonic distortion, and under complete control
- Comprehensive side chain EQ giving simultaneous control of frequency and level of filtering for the low and high bands This works in conjunction with the rear panel stereo insert points that provide even further control
- Variable Wet/Dry Mix plus Output Gain Knobs give a ‘Parallel Compression’ function without the need for external mixing devices, providing Complete and Effortless Control over the amount of compression used and Output Levels
- Two Analogue V.U. Meters with Switchable +10dB Meter Rescale Mode
- These have additional dual colour backlighting that act as a visual indication for the amount of saturation
- Time delay relays on outputs for clean power up/down
- Internal Low Hum Toroidal Linear Power Supply with Voltage Selector Switch
- Classic Drawmer Build Quality with Rugged Steel Chassis and Aluminium Front Panel
- Designed and manufactured by Drawmer in the UK
Mix Control – Pricisely Control the Amount of Compression Applied!
Incorporated into the 1961 is the ‘Mix’ Control. This acts like a ‘parallel compression’ effect that mixes the Wet (compressed) and Dry (original) signals to provide a simple and exact way of controlling the amount of compression used – all with the turn of a single knob.
With the extensive controls of the 1961, such as saturation and tonal shaping, it could be possible to take the effects too far and ruin a mix – this is easily prevented by the use of the Mix control just by mixing in less of the wet signal and more dry. By the same token, the mix control can add more compression and character simply by adding more of the wet signal. It’s that simple!