Buzz Audio req-2.2 User Manual

REQ-2.2 USERS MANUAL VERSION

-

2, MAY 2009

. CONTEN

TS COPYRIGHT BUZ

Z AUDIO LTD 2008

.

REQ-2.2 Resonance Equalizer

Users Manual

PO BOX 6677, TE ARO. WELLINGTON, NEW ZEALAND. PH. [phone]

www.buzzaudio.com email [e-mail]

Welcome…

Welcome…

Welcome…Welcome…

Thank you for choosing the Buzz Audio REQ-2.2 Resonance Equalizer. In this
manual you will find important information regarding the use of the REQ
and we suggest you do read it before using the unit to become familiar
with all the controls and their function.

If after unpacking the REQ you find any damage to the unit you should
contact your dealer or supplier immediately for advice on what to do.

We also suggest you retain the original packaging at least during the
warranty period in case you need to return the unit for service, however we
are confident this will not be necessary!

Contents…

Contents…

Contents…Contents…

Page

1] Installation Precautions....................................................... 3

2] The Mains Input .................................................................. 3

3] Audio Connections............................................................. 4

4] Overview ............................................................................ 5

5] Controls .............................................................................. 6

6] Specifications..................................................................... 8

7] Warranty/Service Information.............................................. 9

8] Recall Sheets ................................................................... 10

9] Graphs ............................................................................ 12

2

1] Installation

1] Installation Precautions

1] Installation1] Installation

The REQ-2.2 uses discrete Class A audio amplifiers and these along with the
power supply generate a fair amount of heat. Whilst the casing has many
ventilation holes, care should be taken to avoid racking the REQ along side
other units that run hot. If possible, allow ventilation space between the
REQ and other hot running boxes.

If the REQ becomes too hot, internal parameters may change and this may
show up as clicks when switching the EQ bands in and out.

The REQ also uses wound chokes (inductors) and because these are coils of
wire with many turns, they are prone to picking up mains hum and other
noise in the environs. The REQ chokes are contained within steel housings
to minimize hum induction, however avoid mounting the REQ next to
devices with large unshielded power transformers or switching power
supplies.

2222] Th

] The Mains Input

e Mains Input

] Th] Th

e Mains Inpute Mains Input

As a safety precaution your REQ maybe shipped without a mains fuse fitted.
Before use, you must select the correct mains voltage for your local supply
on the rear panel and fit the correct mains fuse type into the fuse draw for
that voltage.

The factory or your dealer may have already set all this up for you but it
pays to check it before powering up the REQ.

• Setting the Voltage Selector…

Setting the Voltage Selector…

Setting the Voltage Selector…Setting the Voltage Selector…

You will need a medium size flat blade screwdriver.

If your local mains voltage is 100V to 120V set the rear panel voltage
selector to 110V.
If your local mains voltage is 220V to 240V set the rear panel voltage
selector to 220V.

PLEASE

PLEASE NOTE

PLEASE PLEASE
MAY CAUSE SEVERE AND PERMANENT INTERNAL DAMAGE!

• Selecting

In the supplied accessories bag you will find;
2x 1 Amp slow blow fuses, FIT for 220V to 240V.
2x 2 Amp slow blow fuses, FIT for 110V to 120V.

NOTE - POWERING UP THE REQ WITH THE WRONG VOLTAGE SETTING

NOTENOTE

Selecting the Correct Fuse…

Selecting Selecting

the Correct Fuse…

the Correct Fuse…the Correct Fuse…

Precautions

Precautions Precautions

3

Slide out the fuse draw below the IEC power inlet using a small flat blade
screwdriver and insert the appropriate fuse into the carrier clip. Note there
is also a position in the carrier for a spare fuse (the square tube bit) and we
suggest you store the second supplied appropriate fuse here.

Fitting the wrong fuse may result in the fuse blowing on power up or
inadequate protection. Fitting a fast blow type fuse may also result in the
fuse blowing on power up.

3333]

] Audio

Audio Connections

] ]

Audio Audio

All the XLR connectors on the rear of the REQ-2.2 are balanced and wired
as follows;

Pin 1 = Chassis Ground
Pin 2 = Signal Hot (+)
Pin 3 = Signal Cold (-)

The REQ will accept both balanced and unbalanced inputs, however we
do recommend the use of balanced lines where ever possible. The REQ
has a “looping” input, allowing you to daisy chain it with another device. It
also has two output connectors (paralleled) enabling you to feed two
separate devices if desired.

The REQ output will drive both balanced and unbalanced loads due to our
unique BE44 Discrete Class A line driver module. If the load is unbalanced,
the BE44 will automatically detect this and adjust the output level
accordingly. We do recommend however that balanced loads are utilised
where ever possible for best sonic performance.

PLEASE

PLEASE NOTE

PLEASE PLEASE
OUTPUT XLR’S MAY CAUSE DAMAGE TO THE BE44 MODULE.

NOTE: A LONG TERM SHORT CIRCUIT BETWEEN PIN 2 AND PIN 3 OF THE

NOTENOTE

Connections

ConnectionsConnections

4

4444]

] Overview

Overview

] ]

OverviewOverview

The REQ-2.2 is a stereo audio equalizer with four “eq” bands per channel
plus a high pass filter and unique “saturation” module. Front panel controls
allow you to adjust each eq band centre frequency, filter bandwidth (or Q)
and the amount of cut/boost. Each element has it’s own on/off switch
which removes it from the signal path when off.

The high and low bands can be switched from a bell filter to a shelving
filter, and the bandwidth control reverts to a shelf slope control when in
shelf mode. The mid bands can be switched between two frequency
ranges as indicated on the front panel.

There are two versions of the REQ, the standard version and a mastering
version. The differences between the two versions are the high pass filter
turn over frequencies (see graphs at the end of this manual), and the
cut/boost controls. The mastering version utilizes a 23 position stepped
attenuator (+/-8dB range) for the cut/boost control, whilst the standard
version offers a continuously variable +/-16dB range with centre detent.

The REQ uses real chokes and capacitors in a parallel resonant circuit
configuration to generate the eq shapes, and this is why it is called the
Resonance Equaliser. Whilst difficult to implement with adjustable
bandwidth, the sound of these passive resonate circuits is far superior to
that of electronically simulated filters.

Unique to the REQ-2.2 is the saturation module which when engaged, adds
subtle amounts of harmonic distortion to the signal and also alters the low
frequency response (see graphs for detail). The saturation module utilizes a
steel core transformer driven by a “single ended” amplifier to achieve this
effect, and is useful in creating a more “vintage” sound. The effect of the
saturation is dynamic in that the higher the signal level, the greater the
effect will be.

5

5555]

] Controls

Controls

] ]

ControlsControls

EQ Band Controls

EQ Band Controls

EQ Band ControlsEQ Band Controls

FREQUENCY

FREQUENCY – each band has a 12 position frequency control which sets

FREQUENCYFREQUENCY
the centre frequency of the filter. The two mid bands have two ranges of
frequency, and the blue lettering applies when the FREQ x2.5
illuminated.

BANDWIDTH

BANDWIDTH (low mid and high mid) – a 12 position switch to set the width of

BANDWIDTHBANDWIDTH
the bell filters ranging from 2 octaves to 0.25 octaves wide. See the graphs
at the end of this manual for more detail.

BANDWIDTH/

BANDWIDTH/SLOPE

BANDWIDTH/BANDWIDTH/
switched into shelf mode (BELL/SHELF
control reverts to a shelf slope control in this mode. Position 2 is a steep
slope whilst position 13 is a more gentle curve. See the graphs at the end
of this manual for more detail.

6

SLOPE (low and high bands) – the low and high bands can be

SLOPESLOPE

BELL/SHELF switch illuminated), and the bandwidth

BELL/SHELFBELL/SHELF

FREQ x2.5 switch is

FREQ x2.5FREQ x2.5

CUT/BOOST

CUT/BOOST – adjusts the amount of eq applied to the signal. The above

CUT/BOOSTCUT/BOOST
drawing shows the standard version with +/-16dB range. The mastering
version of the REQ has a stepped +/-8dB range.

ON

ON – when this switch is illuminated, the associated eq band is engaged

ONON
into the signal path. When switched off, the eq band is completely
removed from the signal path.

PEAK

PEAK – this red LED will illuminate when levels within the REQ circuitry

PEAKPEAK
approach +22dBu warning of possible internal overload. Levels are
monitored at critical points throughout the REQ signal path.

Master Section Controls

Master Section Controls

Master Section ControlsMaster Section Controls

HHHHIGH PASS FILTER

IGH PASS FILTER – a 6 position switch to select roll off frequency of the high

IGH PASS FILTERIGH PASS FILTER

pass filter (HPF). The associated ON

ON switches engages the filter when

ONON

illuminated. The drawing above shows the HPF frequency choices for the

7

standard version. The mastering version has a different set of frequencies
optimized for stereo program equalisation. See the graphs at the end of
this manual for more detail.

SYSTEM

SYSTEM – these switches are used to completely bypass the REQ. When not

SYSTEMSYSTEM
illuminated, the REQ input XLR connectors are directly connected to the
output XLR connectors providing a hard wire bypass. Note that the REQ still
does receive signal at it’s input when bypassed.

SATURATION

SATURATION – this 6 position switch selects the type of saturation applied to

SATURATIONSATURATION
signal. The associated ON

ON switches engages the saturation circuit when

ONON
illuminated. The saturation control changes the low frequency response of
the REQ as well as introducing low frequency harmonics generated by the
steel audio transformer. See the graph at the end of the manual for detail
on the frequency response changes for each switch position. The
harmonic distortion generated by the saturation circuit is given in the
specifications section.

6666] Specifications

] Specifications

] Specifications] Specifications

Frequency Response

Frequency Response

Frequency ResponseFrequency Response

Measured with all eq bands ON set flat, Saturation and HPF OFF........5Hz to 125kHz +0.2/-3dB

See graphs for typical eq and HPF frequency response measurements.

Harmonic Distortion

Harmonic Distortion

Harmonic DistortionHarmonic Distortion

At +10dBu, Saturation OFF .......100Hz 0.007%...1kHz 0.004%...10kHz 0.007%...100kHz 0.013%

Saturation ON POS-1 ........................................20Hz 1.5%...100Hz 0.07%...1kHz and up 0.01%

Saturation ON POS-2 ........................................20Hz 1.5%...100Hz 0.14%...1kHz and up 0.01%

Saturation ON POS-3 ........................................20Hz 1.5%...100Hz 0.16%...1kHz and up 0.01%

Saturation ON POS-4 ........................................20Hz 1.6%...100Hz 0.17%...1kHz and up 0.01%

Saturation ON POS-5 ........................................20Hz 1.7%...100Hz 0.18%...1kHz and up 0.01%

Saturation ON POS-6 ........................................20Hz 2.0%...100Hz 0.22%...1kHz and up 0.01%

Maximum Input Level

Maximum Input Level.....................................................................................................+25dBu

Maximum Input LevelMaximum Input Level
Input Impedance

Input Impedance ........................................................................................... approx 20k ohms

Input ImpedanceInput Impedance

Maximum Output Level

Maximum Output Level ............................................+32dBu balanced…+26dBu unbalanced

Maximum Output LevelMaximum Output Level
Output Impedance

Output Impedance...........................................................................................approx 70 ohms

Output ImpedanceOutput Impedance

In

Input Common Mode Rejection

put Common Mode Rejection (ref 0dBu) ................. 100Hz -65dB…1kHz -65dB…10kHz -60dB

InIn

put Common Mode Rejectionput Common Mode Rejection

Noise

Noise all bands ON set flat........................................-110dB below max input level A weighted

Noise Noise

General

General

GeneralGeneral

Power requirements .......................................................... 115V/230V selectable on rear panel

Dimensions................................................................................... 4U rack mount, 300mm deep

0dBu = 0.775V RMS in these specifications. Specifications are typical of a production unit, and subject to change if
we improve something.

8

7777]

REQ-2.2 USERS MANUAL VERSION

-

2, MAY 2009

. CONTEN

TS COPYRIGHT BUZZ AUDIO LTD 2008

.

] Service Information

Service Information

] ]

Service InformationService Information

We are confident that you will receive many years of trouble free operation
from your unit. If however you experience any technical problem with your
REQ, contact your dealer or Buzz Audio for recommendations on what to
do. The modular nature of the REQ construction means most electronic
faults can be easily repaired by swapping out the circuit boards.

For on line support visit our web site; www.buzzaudio.com

Buzz Audio, PO Box 6677, Wellington 6141, New Zealand.
Phone +64+4+472-3084. Email; [e-mail]

Product Warranty

Product Warranty

Product WarrantyProduct Warranty

• Disclaimer

Disclaimer

DisclaimerDisclaimer

Buzz Audio is not liable for any damage to microphones, amplifiers,
consoles, speakers or any other equipment and/or electric shock to
humans that is caused by negligence or improper installation and/or use of
the REQ-2.2 Resonance Equalizer.

• Standard Product Warranty

Standard Product Warranty

Standard Product WarrantyStandard Product Warranty
Buzz Audio guarantees the REQ-2.2 Resonance Equalizer to be free of
defective materials and/or workmanship for a period of 1 year (12 months)
from the date of sale, and will replace defective parts and repair
malfunctioning products under this warranty when the defect occurs under
normal installation and use – provided the unit is returned to our factory (or
duly authorised service centre) via prepaid transportation with a copy of
the proof of purchase, ie, sales receipt. This warranty provides that
examination of the returned product must indicate, in our judgement, a
manufacturing defect. This warranty does not extend to any product that
has been subjected to misuse, neglect, accident, improper installation, or
where the date code has been removed or defaced. The standard
warranty is NOT transferable.

• Product Warranty Extension

Product Warranty Extension

Product Warranty ExtensionProduct Warranty Extension
The above Warranty may be extended to a period of 2 years (24 months)
from date of sale provided the enclosed Warranty Registration card is
completed and returned to the office of Buzz Audio within 4 weeks (28
days) from purchase date. Alternatively, you may Register your purchase
on-line at our web-site www.buzzaudio.com. The Extended Warranty is
transferable.

PO BOX 6677, TE ARO. WELLINGTON, NEW ZEALAND. PH. +64+4+472-3084.

www.buzzaudio.com email [e-mail]

9

10

11

9] Graphs

12

9] Graphs

9] Graphs9] Graphs

12

13

14

15

16

17