Hafler IRIS User Manual
Hafler Iris Preamplifier
It is a good habit to turn down BOTH remote and main
panel volume controls upon system shut-down. This
will avoid possible sudden and unexpected changes in
volume when system is re-activated.
TABLE OF CONTENTS
Introduction
installation
Operation
IRIS Block Diagram
Using the IRIS Remote System
Introduction
Operation
Specifications
Warranty
INTRODUCTION
Your IRIS preamplifier combines superb, all-discrete, J-FET
amplification stages with unique control methods allowing
unprecedented flexibility and convenience. In this manual,
beyond telling you how to use IRIS, we will try to convey the
spirit and method of how this unusual combination was achieved.
The J-FET devices share many technical and sonic charac-
teristics with the best of vacuum triodes. They also allow things
vacuum tubes
low noise.
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don't
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5
INSTALLATION
The gloss black insert on the face-plate of your new Hafler
Equipment has been packaged with a removable protective
coating. Please peel off this protective coating following in-
stallation.
When cleaning the face-plate, we advise a soft cotton cloth with
a non-abrasive cleaner that is safe for lexan and painted
surfaces. DO NOT use paper towels or any coarse material to
clean the face-plate as these materials may scratch the insert.
IRIS is shipped with styled end caps on its front panel.
mounting ears are available from the factory for standard
wide racks.
In locating IRIS, keep these factors in mind:
1) All preamplifiers with high-gain moving-coil phono circuitry
can be susceptible to pickup of hum from strong external
magnetic fields. Such fields are usually strongest from power
amplifiers, but can also come from other equipment. When
stacking or racking your equipment, you may have to do so as
to minimize this potential problem.
IR
2) The
the dark red screen above the Record 1 switch. The IRIS
remote system combines a powerful transmitter and very
sensitive receiver, resulting in highly reliable communication
under conditions where many remotes will not work. However,
best operation usually results if the preamplifier is located AT or
ABOVE the height at which you will typically use the transmitter.
3) It is also desirable that the IR “eye” not have to look directly
at extremely bright light sources, particularly those of fluorescent nature. Such conditions can impede communication reliability.
(infrared) “eye” for the IRIS remote system is behind
Rack-
19”-
2
Power IRIS is internally connectable for virtually all AC line-power
Connections systems. Units not marked otherwise, on the rear panel, are
connected for 120 Vofts, 50-60 Hz.
Two SWITCHED outlets and one UNSWITCHED outlet (U.S.
120 Volt standards) are provided on the rear panel. The
UNSWITCHED outlet is provided for powering certain mechanical equipment, if so recommended by its manufacturer.
The SWITCHED
a total (for
outlets
all
outlets) of 580 Watts (continuous-rating).
can be used for all other devices up to
The IRIS power switch is very rugged and can sustain the
on surge of large amplifiers. However, some audio purists
prefer to connect large power amplifiers through alternate
supply arrangements to minimize any added magnetic fields in
the low-signal environment of their preamplifier.
Input IRIS employs a very low-noise, high-gain,
Connections
symmetry phono circuit of selectable gain, derived from our
and Selection U.S. patent
(Phono)
the PHONOKEY and then, processed the same as other HIGH
LEVEL inputs.
The phono inputs (gold jacks) are compatible with normal
MOVING-MAGNET and HIGH-OUTPUT MOVING-COIL
cartridges (typically 2-5
COIL cartridges (typically
ohms, except when optional cartridge loading is employed.
This is discussed at the end of this manual.
The rear-panel (MM/MC) switch (next to the phono jacks), when
depressed, increases phono-stage gain by 20dB for
OUTPUT MOVING-COIL cartridges.
4,496,910.
turnline-
complementary-
The phono stage output is selected by
mV),
and LOW-OUTPUT
0.2-0.5 mV).
Input impedance is 47k
MOVING-
LOW-
CAUTION:
Never operate this switch, either way, unless the VOLUME
control is turned full down, as the very high gain present can
result in switching transients able to blow fuses in amplifiers or
loudspeakers, or damage some types of loudspeakers.
3
The usual ground thumbscrew is provided for turntable-frame
grounding via the extra ground wire provided on most turntables.
High Level
Inputs
IRIS has seven pairs of main HIGH LEVEL inputs, selected by
the seven (oval) KEYS to the right of the phono KEY. All of these
(Oval Key inputs proceed at unity gain to the attenuator/line-amplifier
selected) system, which has a maximum gain of 20dB.
All of these basically identical inputs are selectable by the input
KEY switches. The KEY switches activate a digital system
which effects audio-signal selection by FET switches, followed
by matched J-FET buffers.
Excepting phono, all input impedances, for the entire preamplifier, are in the 15-28k ohms range.
To get you to the basic operation of IRIS as quickly as possible,
we have deferred the discussion of EPL and TAPE loops to a
later section.
Main Outputs The MAIN output jacks are used to feed the power amplifier.
and
Mono switch
Their low output impedance of 316 ohms allows driving long
cables if necessary.
The MONO switch effects a passive combining of the stereo
channels into monaural, fed through the attenuator system to
both line amplifiers. Although rarely used today, this switch is
provided for the optimum reproduction of treasured mono
recordings, and can be employed to check for exact system
balance.
It is highly recommended that where you may have a constant
monaural source, such as a mono TV, that you secure a
“Y”
splitter from an electronics store and feed both preamp channels in parallel. This makes remote operation easier, and
avoids accidentally leaving MONO engaged when you switch
back to a stereo source.
OPERATION
CAUTION:
later, are often the cause of an apparently “dead” system, when
they have accidentally been left engaged. Always check them
first if a system is found “dead” on turn-on. For now, make sure
that all six of the group of round-button switches are in theirOUT
position.
The EPL switch and the tape MONITOR switches, explained
Turn-On/Off
logic
Muting System
When IRIS is powered-up, the MUTE legend will light alone,
along with a small GREEN indicator, between the knobs, called
the VOLUME/BALANCE (V/B) indicator. The V/B indicator
shows that the IRIS panel knobs are determining VOLUME and
BALANCE. Its operation is explained in the remote section.
During this period, none of your KEY inputs will be accepted into
memory. This period is about five seconds, during which the
MAIN outputs of the preamplifier are muted.
At the end of this turn-on safety period, the MUTE indicator will
go out and the TUNER legend will light. TUNER mode is
designed as a reset state to facilitate easiest turn-on for
background music etc. Any of the other seven inputs may now
be selected by their appropriate KEY.
The MUTE KEY causes the MUTE light to illuminate, and the
preamp to fade down approximately 20dB. This mode is used
for phono cueing and at any other convenient time, such as
answering a phone etc. Depressing the
normal level. The two-key format is used so that you always
know whether you are muting or de-muting.
NORMal
KEY restores
Volume/
Balance System
The level-control system in IRIS is unusual and uniquely suited
to our goal of combining superb sound with high convenience.
It is an indirect type in which no audio signals are passed
through the panel controls.
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