Sound Performance Lab . Qure . in detail

Qure
Model 9738

In D e t a i l

Concept

The Qure is a fully parametric equaliser designed to meet the most demanding studio applications. It is a 3-band, two-channel system with input and output gain controls, high-cut and low-cut filters as well as the new QURE control for the enhancing presence and room imaging of vocals, instruments and complex stereo material. The effect of the Qure control can be use to place signal in front of the mix very effectively.
Both balanced XLR and balanced stereo jacks are provided for signal connections to and from the Qure.
The proportional-Q principle provides precise control over a frequency range, from 15Hz to 21kHz, while the low noise level of -99dB (A-weighted) and the enormous dynamic range of 113dB ensure excellent audio qualities.

The QURE control

The Qure circuitry gives the name for the unit and also represents a new technology which employs coil filters to influence presence and spatial imaging. At the same time it is ideally suited to "cure" recordings, e .g. from digital harshness.
The signal runs through a tube circuitry featuring an 12AX7-LPS double triode tube in a mixed current/voltage coupling mode. This stage is extremely clip-resistant and produces a pleasant and musical sounding tube-THD spectrum. The Qure On switch puts a coil/condenser/resistor filter network (LCR) into the tube output stage. This network is integrated into the coupling path of the tube and reacts on the dynamic response of the input signal by influencing THD spectra and phase response. The Qure potentiometer changes the frequency response and produces a fresh and silky top-end and a mid-range free of sharpness and harshness. For example, vocals can be "placed" in the front of a mix without having to provide more "space", also background or layer sounds can gain improved spatial depth.

Proportional Q

Unlike most other equalisers which use constant-Q filters, the Qure adopts the proportional-Q principle to realise maximum musicality. Conventional constant-Q designs keep the amplitude constant, regardless of the adjusted bandwidth (Q). The disadvantage of constant Qs insound creation: frequencies above and below the centre frequency are often boosted so intensely that musicality is lost. With proportional-Q it is quite different; the amplitude of the processed frequency band is reduced as the bandwidth broadens. Adjusting the bandwidth back to a narrow bandwidth (high Q) will increase the amplitude of the centre frequency to its former level. Furthermore, with proportional-Q, there is no need to constantly readjust the boost/cut control when varying the bandwidth.

The Frequency Bands

The Qure is configured as a two-channel, 3-band equaliser with a separate hard-bypass switch for each band. The filters are connected in series. The three filters bands cover a frequency range from 15Hz to 21kHz. In addition each channel features high- and low-cut filters. The perfectly linear phase response of the Qure circuitry, combined with its wide bandwidth, contributes to the sonic excellence of this esoteric equaliser. The mid-band features the "non-reciprocal response of the Boost/Cut control which qualifies this band to operate as a notch filte, too. Cutting is allowed to -36dB at high Q (Q5) whereas the low and high band offer cutting of -15dB. The sonic advantage of the "non-reciprocal response design is the vast dynamic response making the filter sound very open and clear.

General Features

To allow easy recall of all control settings the Qure is equipped with stepped potentiometers throughout. The number of steps is optimised to the control function: 11 steps for bandwidth, 31 steps for frequency and boost/cut, and 41 steps for input gain, HF/LF Cut filters, and Qure control. Each band can individually be switched in and out of the signal path making comparison easy. Each filter is mounted on a separate printboard featuring a central ground shielding layout for maximum rejection of interfering frequencies. Single op-amps are used throughout to minimize noise and THD. Custom made condensers and frequency controls are featuring a control characteristic for gentle frequency sweeps with perfectly musical balance.

Specifications

Input & Output

Instrumentation amplifier, electronically balanced (differential), transformerless
Nominal input level +6dB
Input impedance = 22 kOhms
Output impedance < 600 Ohms
Max. input level +14dBu
Max. output level +20dBu
Minimum load ohms 600 Ohms
Relay Hard Bypass
Power Fail Safety

Measurements

Frequency response:10Hz 100kHz(100kHz = -3dB)
EQ frequency range: 15Hz 21kHz
CCMR: > -80 dB @ 1 kHz
THD & N: 0,01855% @ 1kHz
S/N CCIR 468-3: -85dBu
S/N A-weighted: -99dBu

Power Supply

Toroidal transformer 35 VA
Fuse (primary) 500 mA (230V/50Hz), 1000 mA (115V/60Hz)
Ground-Lift switch, Voltage selector 115V/230V

Dimensions

Housing Standard EIA 19"/2U, 482 x 88 x 237mm
Weight 4,9 kg
Note: 0dBu = 0.775 V

Subject to change without notice.