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H A - 6 A B / H A - 6 A B E M a n u a l
ers, selected by pressing front panel pushbuttons. mic stand, providing two headphone jacks, each
Without the HA-6AB, a separate amplifier would with its own volume control. Up to twelve HR-2
be needed for the studio speakers. The HA-6AB boxes may be connected to a HA-6AB, employing
also features a convenient input level control on standard microphone cables (depending on the
the left side of the front panel. A pair of yellow impedance of the headphones used).
LED’s (one for each channel) light up whenever a
signal is present.Another pair of red LED’s shows
USES OF HA-6AB
an overload condition in either channel.
The HA-6AB may be used as a power ampli-
The Furman HA-6AB’s 20 watts-per-channel
fier to drive up to two pairs of speakers, or as a
make it ideal as a low distortion headphone driver
headphone amplifier for one to six pairs of head-
for the most critical listening situations. While
phones, or both. Additional headphones may be
most headphone amplifiers provide half a watt or
connected through use of HR-2 Remote Boxes.
less per headphone channel, the HA-6AB’s higher
power can drive headphones of any impedance RECORDING
to their full rated listening level, and do so with
In the recording studio, headphones are most
minimal noise and distortion. Its power capacity
often used in the overdubbing process, whereby
is also just right for the small near field monitors
new musical tracks are recorded in synchro-
used in most recording studios; as a comparison
nization with previously recorded tracks. The
with the main control room monitors, it can power
musicians doing the overdub hear the previously
them without overpowering them. On the studio
recorded tracks in their headphones, and play
floor, a set of small monitor speakers driven by
along with them. Synchronization is maintained
the HA-6AB can make a session progress more
because almost all multitrack recorders have the
efficiently by giving the musicians a chance to
capability of playing back through certain chan-
hear a playback without needing to disconnect
nels of the record head while recording through
themselves from their equipment and walk into
others. In this way, it is possible to build up a
the control room.Additionally, the HA-6AB is fully
complete recording of many tracks, adding one
protected against thermal overload, and it can
or more new tracks with each overdub.
withstand a short circuit on any or all outputs for
Headphones are much preferred to speakers for
an indefinite time without damage.
cueing the overdub, because of the presence of
open microphones which would pick up the cue
ACCESSORIES
tracks as well as the overdub.Any trace of the cue
tracks in the overdub tracks would degrade the
Model HR-2 Headphone Remote Station: A
tracks’ separation and make it difficult to achieve
compact, unobtrusive box that clamps to any
a good mix later on. In fact, even if headphones
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H A - 6 A B / H A - 6 A B E M a n u a l
are used, it is important that they clamp tightly to HA-6AB itself is installed in the control room. In
the musicians’ heads so that a minimal amount this arrangement, the Speaker buttons will be
of sound leaks out.
more easily accessible to the engineer, and each
musician’s volume control will be right on the mic
stand in front of him or her. And of course, if the
engineer or others in the control room want to
hear the cue mix, they can just plug headphones
into any of the HA-6AB’s front panel jacks. See
the section on “Use of the HR-2 Remote Stations”
for additional details.
The cue mix heard in the headphones is a com-
bination of the previously recorded tracks along
with the new sounds being added. It is generally
derived from a “Cue” or “Headphone” mixing buss
on the recording console, which is then routed to
the Left and Right Inputs on the HA-6AB’s rear
panel. If this mix is mono, connect it to the Left
Input. The HA-6AB will then automatically be in NOTE: For studios that require each tracking mu-
mono mode, so that the mix can be heard with sician to have their own personalized mix, the Fur-
both ears (and both speakers, if used).
man HDS-6/HR-6 or the HDS-16/HRM-16 may be
required as an alternative to the HA6-AB.
In a small studio, if no more than six sets of head-
phones are needed, it may be most convenient to The HR-2 Remote Stations connect in “a daisy
locate the HA-6AB on the studio floor, and plug all chain” fashion to the Speaker B output on the
headphone sets directly into its front panel. You rear panel of the HA-6AB. This output is an XLR
may want to put a large, easily readable number connector, so that standard microphone cables
on each set so that each musician will be able to can be used. The HA-6AB connects to the first
locate his or her volume control, even if the cables HR-2 box; another mic cable connects the first
become tangled.
HR-2 box to the second HR-2 box; a third mic
cable connects the second HR-2 to the third
HR-2; and so forth. However, twelve HR-2 is the
recommended maximum.
In a larger studio, you may find it more practi-
cal to use several HR-2 Remote Stations at
strategic locations around the studio, while the
Daisy-chaining HR-2 Remote Stations to the HA-6AB
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H A - 6 A B / H A - 6 A B E M a n u a l
One or two sets of studio speakers may be con-
USE OF THE HR-2 REMOTE
nected to the HA-6AB. If two sets are needed,
the “B” pair must be connected to the XLR output
using a custom made cable. HR-2 Remote Sta-
tions cannot be used in this case.
STATIONS (SATELLITES)
The HR-2 Remote Stations may be used to
increase the number of headphones which can
be accommodated by an HA-6AB, and to place
a volume control within reach of each individual
needing it. They are compact boxes which eas-
ily attach with a thumbscrew to any microphone
stand. Each HR-2 has two stereo volume controls
and two headphone jacks. There are also two
XLR connectors, one male and one female. These
may be used to “daisy chain” HR-2 boxes together
with standard microphone cables. Begin the chain
at the SPEAKER B - SATELLITE/REMOTE con-
nector on the rear of the HA-6AB. The HA-6AB
connects to the first HR-2 box; another mic cable
connects the first HR-2 box to the second HR-2
box; a third mic cable connects the second HR-2
to the third HR-2; and so on. If low impedance
headphones are used, up to twelve HR-2’s may
be in the chain. If medium or high impedance
headphones are used, 25 or more Remote Sta-
tions may be chained. If desired, the clip on an
HR-2 box may be hung on a belt if no microphone
stand is convenient.
REHEARSAL
Headphones are used in rehearsal sessions
not only to avoid disturbing neighbors with loud
sounds, but also to provide each musician an
easily controlled mix of all the other tracks. Us-
ing headphones guarantees that each will hear a
balanced mix regardless of where they are posi-
tioned relative to various instruments or speakers
(a luxury not always available in performance).As
in recording, a mixing board must be used, whose
output will drive the HA-6AB either in mono (use
Left Input only) or stereo (use both inputs).
The main consideration in locating the HA-6AB is
whether each musician will need easy access to
his or her own volume control. If the musicians are
spread around a large room, the use of a chain of
HR-2 Remote Stations may be more convenient
than having each pair of headphones plug directly
into the HA-6AB.
LANGUAGE LABS
Language labs occasionally need to drive as
many as 50 headphone sets. If more than twenty
five sets are required, they must be high-imped-
ance types. HR-2 Remote Stations provide a
convenient way to place a volume control at
each listening position (two listeners can share
each box).
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H A - 6 A B / H A - 6 A B E M a n u a l
triggered, the lights will stay lit for a minimum of
FRONT PANEL
50 milliseconds so they can be easily seen, even
if the actual duration of the overload is much
shorter.
INPUT LEVEL: The Input Level control provides a
means of scaling the effect of the individual head-
phone volume controls. The Input Level should
be adjusted so that there is an adequate range
of volumes available at each listening position,
so that any listener can be accommodated, and
the average listener’s volume will be set at about
halfway. The Input Level control is stereo; it affects
both left and right channels simultaneously.
HEADPHONE JACKS / VOLUME CONTROLS:
Any type of headphones, wired with a standard
1/4” stereo phone plug, may be used success-
fully. All six outputs receive the same stereo
signal. They differ only in the individual volume
settings.
SPEAKER-A BUTTON: Depressing this but-
ton turns on the speakers connected to the
SPEAKER-Abanana jacks on the rear panel, and
simultaneously turns off the signal to all the front
panel headphone outputs.
SIGNALPRESENT LIGHTS: These yellow LED’s
turn on whenever a signal exceeding 125 mil-
livolts RMS (40 dB below full power) is present
at the HA-6AB’s input jack. They will increase in
brightness as the signal strength increases. This
feature is very useful and can provide a clue to
where the fault may lie if the expected program
is not heard at the listening stations.
SPEAKER-B BUTTON: Depressing this button
turns on whatever is plugged into the SPEAKER-
B SATELLITE/REMOTE XLR connector on the
rear panel. This will be either a pair of speakers
or a chain of HR-2 Remote Stations. Therefore,
leave this button depressed when using Remote
Stations. Depressing it does not turn off the front
panel headphone outputs. See the section on the
Rear Panel for speaker wiring.
OVERLOAD LIGHTS: These LED’s glow red to
indicate an overload in the HA-6AB. If the LED
lights up, either the drive level to the unit should
be reduced, or the setting of the Input Level con-
trol should be reduced until the LED remains off.
The lights turn on when the signal level at either
output approaches .5 to 1 dB of clipping. Once
POWER LIGHT: Glows red when unit is receiv-
ing power and the ON-OFF SWITCH is in the
ON position.
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H A - 6 A B / H A - 6 A B E M a n u a l
sis ground). The connection from pin 1 to the shell
REAR PANEL
is optional on all 3 pin connectors, and can be
removed if present, by opening up the connector
on the cable and disconnecting it.
ON-OFF SWITCH: This switch turns the HA-6AB
on and off. For convenience, it is recommended
that the HA-6AB and any other rack-mount
equipment be powered through a switchable
outlet box, such as the Furman Sound PL-8 or
PL-PLUS Power Conditioner and Light Module.
The PL Series provides an easy way to power up
the whole rack with one front-panel switch, and
provides discreet illumination on dark stages and
studios as well. If you do use a switchable outlet
box, leave the HA-6AB’s on-off switch in the ON
position at all times.
SPEAKER A OUTPUTS: These outputs should
be used when a pair of speakers is used as an
alternative to headphones, since the headphones
are switched off when the speakers are switched
on. The connections are 5-way binding posts,
which can accommodate dual banana plugs, bare
wires, or wires terminated in spade lugs.
SPEAKER B SATELLITE/REMOTE OUTPUT:
This output is a single male XLR connector con-
taining both the left and right channel outputs. It
is wired as follows: Pin 3-left (high); Pin 2-right
(high); and Pin 1-low, common to both channels.
This output should be used as the starting point
for a chain of HR-2 Remote Stations (satellites).
It will receive signal whenever the front panel
SPEAKER B button is depressed. If necessary,
it may also be used to connect a second set of
speakers. However, if it is used for speakers, note
that depressing the SPEAKER B button will not
switch off the front panel headphone jacks in the
way that the SPEAKER A button does.
GROUND LIFT SWITCH: In many installations,
hum-causing ground loops are formed by the
common connection of various pieces of equip-
ment to the power line ground, and by contact
between chassis, as in a rack with metal rails.
Sliding the Ground Lift switch up completely
isolates all signal grounds from the chassis,
breaking any ground loops. The chassis always
remains connected to the ground pin on the AC
cord for safety and to provide shielding against RF
interference. Try both positions of the Ground Lift
switch, and leave the switch in the position that
results in the least hum in your system.
INPUTS: Quarter-inch (mono) phone jacks are in-
tended for line level signals such as the outputs of
a mixer. Microphones and/or instrument pickups
may not have strong enough outputs to drive the
Note: The ground lift can be rendered ineffective
by 3 pin audio connectors that tie pin 1 (signal
ground) to the metal shell of the connector (chas-
GROUND
LIFT
SPEAKER A
SPEAKER B
CAUTION!
120 VAC
50/60 Hz
130 Watts
RISK OF ELECTRIC SHOCK. DO NOT OPEN.
REFER SERVICING TO QUALIFIED SERVICE
PERSONNEL. TO REDUCE THE RISK OF FIRE
OR ELECTRIC SHOCK DO NOT EXPOSE THIS
EQUIPMENT TO RAIN AND MOISTURE.
ON
HEADPHONE/
MONITOR
®
®
LEFT
RIGHT
LISTED
7Z37
AVIS:
RISQUE DE CHOC
ELECTRIQUE -- NE PAS OUVRIR
PROFESSIONAL
AUDIO EQUIPMENT
OFF
AMPLIFIER
RIGHT INPUT
LEFT INPUT
SATELLITE / REMOTE
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H A - 6 A B / H A - 6 A B E M a n u a l
HA-6AB directly without first being preamplified. The input connectors are stereo 1/ 4” phone jacks.
The 1/4” phone inputs are stereo jacks (tip-ring- In the HA-6AB, these will be paralleled by XLR
sleeve) wired for a balanced input. If a mono connectors. If a mono plug is inserted, the ring
phone plug is inserted, the input will automatically connection will be grounded through the body of
be converted to unbalanced. If using a mono sig- the plug, converting the differential amplifier to a
nal plug into the left ¼” jack the HA-6AB will send noninverting amplifier. After the buffers, the left
signal to both left and right channels.
and right signals proceed to the two decks of the
The HA-6AB is also equipped with left and right stereo Input Level control.
balanced female XLR connectors in addition to
The HA-6AB’s power amplification is derived from
the standard 1/4” phone jacks. Balanced lines
offer the benefits of cancellation of hum, noise,
and RF interference which may be picked up in
the interconnecting cables. For balanced con-
nections, shielded twisted pair cable must be
used. The wiring is as follows: Pin 1-shield; Pin
2-signal positive; and Pin 3-signal negative. The
XLR inputs can not be used in mono like the ¼”
input jacks.
a pair of LM1875 integrated circuits, which have
internal short-circuit and thermal overload pro-
tection. They are set for a voltage gain of 26 dB.
The LM1875’s drive the speaker outputs directly.
The headphone outputs first pass through special
high-power pots wired as volume controls.
The HA-6AB’s power supply provides +/-24 volts
unregulated to the LM1875 stages, which may
drop to +/-20 volts under full load. A network of
dropping resistors and zener diodes provides ±15
volts to the rest of the circuit.
CIRCUIT DESCRIPTION
Both the Overload LED’s and the Signal Present
LED’s monitor signal levels at the output (before
the volume controls).
CAUTION! This section is intended to assist the
professional user with considerable experience
in electronics to achieve a better understand-
ing of the operation of the HA-6AB. Under no
circumstances should persons without electron-
ics troubleshooting experience and training un-
dertake repairs on their own. There are no user
serviceable parts inside the HA-6AB.All problems
should be referred to the factory or to other quali-
fied service personnel.
INSTALLATION
The HA-6AB is intended for mounting in
standard 19” equipment racks. Standard racks
come equipped with mounting rails with holes
tapped for 10-32 machine screws. Be sure to
use only 10-32 screws (in particular, avoid 10-
24 screws, which will fit if forced but will strip
the threads). To avoid marring the panel when
tightening the screws, use nylon washers under
the screw heads.
The inputs to the HA-6AB proceeds from the
input connectors to op-amplifier buffers wired as
differential (balanced) amplifiers.
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H A - 6 A B / H A - 6 A B E M a n u a l
For best results, the input cables plugged into
the HA-6AB should be shielded. Balanced
connections should use shielded, twisted-pair
cable. Headphone cables and speaker cables
do not need to be shielded, though no harm is
done if shielded cables (such as microphone
cables) are used.
warranty card or on-line website registration.
Shipping charges to the Furman factory or to an
authorized repair location must be prepaid by the
Purchaser of the product. Manufacturer shall, at
its own expense, furnish a replacement Product
or, at Manufacturer’s option, repair the defective
Product. Return shipping charges back to Pur-
chaser will be paid by Manufacturer.
THREE YEAR LIMITED
WARRANTY
Furman Sound, Inc., having its principal place
of business at 1997 South McDowell Blvd.,
Petaluma, CA 94954 (“Manufacturer”) warrants
its HA-6AB (the “Product”) as follows:
THE FOREGOING IS IN LIEU OF ALL
OTHER WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE IM-
PLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FORAPARTICULAR PURPOSE.
Manufacturer does not warrant against damages
or defects arising out of improper or abnormal
use of handling of the Product; against defects
or damages arising from improper installation,
against defects in products or components not
manufactured by Manufacturer, or against dam-
ages resulting from such non-Manufacturer made
products or components. This warranty shall be
cancelable by Manufacturer at its sole discre-
tion if the product is modified in any way without
written authorization from Furman Sound. This
warranty also does not apply to Products upon
which repairs have been affected or attempted by
persons other than pursuant to written authoriza-
tion by Manufacturer.
Manufacturer warrants to the original
Purchaser of the Product that the Product sold
hereunder will be free from defects in material and
workmanship for a period of three years from the
date of purchase. The Purchaser of the product
is allowed fifteen days from the date of purchase
to complete warranty registration by mail or on-
line at the Furman website. If the Product does
not conform to this Limited Warranty during the
warranty period (as herein above specified),
Purchaser shall notify Manufacturer in writing of
the claimed defects. If the defects are of such
type and nature as to be covered by this war-
ranty, Manufacturer shall authorize Purchaser
to return the Product to the Furman factory or to
an authorized Furman repair location. Warranty
claims should be accompanied by a copy of the
original purchase invoice showing the purchase
date; this is not necessary if the Warranty Reg-
istration was completed either via the mailed in
THIS WARRANTY IS EXCLUSIVE. The
sole and exclusive obligation of Manufacturer
shall be to repair or replace the defective Prod-
uct in the manner and for the period provided
above. Manufacturer shall not have any other
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H A - 6 A B / H A - 6 A B E M a n u a l
obligation with respect to the Products or any
part thereof, whether based on contract, tort,
strict liability or otherwise. Under no circum-
stances, whether based on this Limited Warranty
or otherwise, shall Manufacturer be liable for
incidental, special, or consequential damages.
Manufacturer’s employees or representatives’
ORALOR OTHER WRITTEN STATEMENTS DO
NOT CONSTITUTE WARRANTIES, shall not be
relied upon by Purchaser, and are not a part of
the contract for sale or this limited warranty. This
Limited Warranty states the entire obligation of
Manufacturer with respect to the Product. If any
part of this Limited Warranty is determined to be
void or illegal, the remainder shall remain in full
force and effect.
SERVICE
Before returning any equipment for repair, please
be sure that it is adequately packed and cush-
ioned against damage in shipment, and that it is
insured. We suggest that you save the original
packaging and use it to ship the product for ser-
vicing. Also, please enclose a note giving your
name, address, phone number and a description
of the problem.
NOTE: All equipment being returned for repair
must have a Return Authorization (RA) Number.
To get an RA Number, please call the Furman
Service Department, (707) 763-1010, Ext. 120 or
121, between 8 am and 5 pm U.S. Pacific Time.
Please display your RA Number prominently on
the front of all packages.
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Furman Sound, Inc.
1997 South McDowell Blvd.
Petaluma, California 94954-6919 USA
Phone: 707-763-1010
Fax: 707-763-1310
E-mail: [email protected]
081403-B
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