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PRODUCT SHOWCASE
Luggable PA system from Altronics
There are many so-called portable public address
systems around, intended for schools, community
groups, sporting bodies and the like. Most of
these systems are, not to put too fine a point on
it, rubbish. So it’s very refreshing to find a system
which not only works but works well.
The system is the “Black Max”
Portable PA Unit from Altronic Distributors, in Perth. It is described as a
rugged, heavy duty self-contained PA
system and with that we cannot argue.
The first thing you notice about
the unit, even before taking it out of
its carton, is the weight: some 13kg!
That’s why we prefer to describe this
90 Silicon Chip
system as luggable, as distinct from
portable. True, it can be carried from
place to place. True, it doesn’t need
mains power with the optional field
battery pack. True, it is completely
self-contained. But just try carrying
it over any distance and you’ll agree;
it’s portable just like a suitcase full of
bricks is portable!
Not that we are trying to put this
Black Max down. Far from it: that
weight all comes because of the features and performance built in. And
if you want performance, weight is a
small consideration.
To be honest, we’re also speaking
from experience. This is not the first
time we have come across the Black
Max. Our first introduction to the unit
was when, in another life, we needed a
truly portable PA system for use at Surf
Carnivals. Like the man who was so
impressed with the shaver he bought
the company, we were so impressed
with the Black Max we purchased one.
That was over two years ago and until
now, it had done nothing to change
that first impression!
Now, having seen the new model,
we are envious. It’s not only more rugged but sports a range of new features
and even better performance. So what
do you get for your money?
We’ll start with the outside. The
Black Max measures 430mm high,
300mm wide and 210mm deep. It’s
made from heavy duty MDF covered
in a thick crinkle-finish black PVC.
All eight corners of the case are protected by heavy duty ribbed speaker
box corners, as in professional sound
systems, which also double as feet in
either vertical or horizontal direction.
There is an expanding carry handle
on top and a “top hat” mount let into
the base so that the unit can be used
directly with an optional tripod stand
or other mounting system.
Almost the entire front of the unit
is covered with acoustic foam, behind which (and hidden) is a grille
to prevent damage to the speaker.
The speaker itself is a 2-way 200mm
coaxial type.
Rear panel facilities
On the rear panel is the (optional)
logic controlled, auto reverse cassette
deck. While delightfully easy to use,
if we have one criticism of this deck it
is that it has no tape counter. Again,
from experience, using a cassette deck
without a counter in anything but
background music situations can be a
real drawback. Cuing is very difficult,
especially during “events” where various tapes are required.
Below the cassette is the inbuilt
mixer, offering two microphone
channels, both with balanced (XLR)
and unbalanced (6.5mm) sockets
(3mV sensitivity, 200-600 ohms) plus
left and right auxiliary (RCA) inputs
(250mV, 100k impedance), which are
of course summed to mono. Each input
channel has its own level control so
full mixing is available. Unfortunately, however, the auxiliary input level
control also doubles as the cassette
level control, so this can only be used
for one or the other.
The MIC 1 socket also has a switch
which can be set to “wireless mic”
where this option is fitted. The wireless microphone itself bears special
mention, being a fully professional
quality model with performance as
good as any we have used, even in
stage applications.
Unlike some “el cheapo” wireless
microphones which transmit in the
88-108MHz FM band, with obvious
consequences, these microphone use
the “professional” 200MHz band, with
a choice of two frequencies to avoid
other users in the same area. (We
have found the wireless microphone
reliable for up to about 100 metres or
more line-of-sight, but have experienced breakthrough from a club with
a mic on the same frequency almost
1km away!)
A 6.5mm socket is provided for an
extension speaker. There is a matching
speaker available as an option or, the
output can be used for other 8-ohm
speakers. Indeed, when we are using
our (older!) Black Max for beach use,
we usually plug in a low impedance
horn speaker for dramatically increased coverage.
Rounding out the “control panel”
is an IEC mains input socket and an
on/off master switch. Unfortunately,
there is no line level output on this
new model, which precludes one
of the features we have found most
useful on the older model: using it
to drive a larger PA system. We have
found that the older Black Max, with
a wireless microphone, makes a magnificent “front end” for our 350W
beach PA system which we use at
surf carnivals.
BassBox®
Design low frequency loudspeaker enclosures
fast and accurately with BassBox® software.
Uses both Thiele-Small and Electro-Mechanical
parameters with equal ease. Includes X. Over
2.03 passive crossover design program.
$299.00
Plus $6.00 postage.
Pay by cheque, Bankcard, Mastercard, Visacard.
EARTHQUAKE AUDIO
PH: (02) 9948 3771 FAX: (02) 9948 8040
PO BOX 226 BALGOWLAH NSW 2093
STEPDOWN
TRANSFORMERS
60VA to 3kVA encased toroids
Field battery pack
Below all of the controls and inputs
is one of the Black Max’s main features:
a “field battery pack”. This option is
much more than a collection of cells.
Instead, it is a rechargeable pack which
automatically charges when ever the
mains is connected and can be left float
charging indefinitely.
It also contains a DC/DC inverter
so that completely portable operation
is at much the same output level as
mains powered. Charging time from
flat is approximately 10-12 hours and
gives up to eight hours continuous
operation.
The amplifier itself is naturally
hidden from view inside the case. It
is rated at 40W RMS, with a frequency
response of 50Hz to 20kHz and distortion of less than 0.07%.
In use
The most immediate reaction is the
quality of sound reproduction. For a
small “PA”, it’s almost “hifi”!
With 40 watts to play with (and a
genuine, measured 40 watts RMS, not
the figment of someone’s imagination
Harbuch Electronics Pty Ltd
9/40 Leighton Pl. HORNSBY 2077
Ph (02) 476-5854 Fx (02) 476-3231
in the back blocks of Taipei), the sound
level is more than adequate for a quite
large hall. We have used the system at
the local high school hall on a number
of occasions, with excellent results.
With the optional extension speaker
added on, the sound spread is, as one
would expect, even better.
It also performs more than acceptably outside, especially when the
unit is mounted a metre or so off the
ground. For this reason, we think that
the optional heavy-duty stand is a
must have item!
One thing we have found from
July 1996 91
experience, and many people have
commented on, is the lack of acoustic
feedback, even when working very
close up and at high levels. There is
nothing more annoying that being
subjected to a PA system either on
the verge of, or actually, breaking into
feedback. You really do have to put the
mic virtually in front of the speaker
to make this one misbehave! For this
alone the designers of the Black Max
must take top marks!
extension speaker, with 20-metre lead,
sells for $279; the heavy duty tripod
stand $140; and the field battery pack
$395
All items are available through Altronics Distributors in Perth (09) 328
2199 or their authorised distributors.
(R. T.)
Boundary mics for
permanent installation
How much
Performance of this type does not
come cheap. But, as the man says, “ya
gets what ya pays for”!
The Black Max standard system (ie,
unit with hard-wired microphone and
no cassette player) has a recommended
retail price of $595. With the wireless
microphone receiver it jumps to $849,
and with the cassette recorder as well
it retails for $1190.
Note that these prices do not include the wireless microphone itself:
the hand-held model (as reviewed)
sells for $335, guitar transmitters are
available for $269 and lavalier (clipon) mics are $379.
The other options mentioned: the
Amber Technology announces the
new Beyerdynamic MPC 22/23 Acoustic Boundary Microphones, designed
for permanent installation into table
tops or ceilings. With a diameter of
only 30mm, the microphones are
suitable for recording and sound
reinforcement applications requiring
high quality reproduction of speech,
including telephone and video conferencing systems, in board
rooms,
courtrooms and churches.
KITS-R-US
PO Box 314 Blackwood SA 5051 Ph 018 806794
TRANSMITTER KITS
•• FMTX1
$49: a simple to build 2.5 watt free running CD level input, FM band runs from 12-24VDC.
FMTX2B $49: the best transmitter on the market, FM-Band XTAL locked on 100MHz. CD level input 3
stage design, very stable up to 30mW RF output.
•• FMTX2A
$49: a universal digital stereo encoder for use on either of our transmitters. XTAL locked.
FMTX5 $99: both FMTX2A & FMTX2B on one PCB.
•connector
FMTX10 $599: a complete FMTX5 built and tested, enclosed in a quality case with plugpack, DIN input
for audio and a 1/2mtr internal antenna, also available in 1U rack mount with balanced cannon
input sockets, dual VU meter and BNC RF $1299. Ideal for cable FM or broadcast transmission over
distances of up to 300 mtrs, i.e. drive-in theatres, sports arenas, football grounds up to 50mW RF out.
FMTX10B $2599: same as rack mount version but also includes dual SCA coder with 67 & 92kHz subcarriers.
•
AUDIO
•soldDIGI-125
Audio Power Amp: this has been the most popular kit of all time with some 24,000 PCBs being
since 1987. Easy to build, small in size, high power, clever design, uses KISS principle. Manufacturing
rights available with full technical support and PCB CAD artwork available to companies for a small royalty.
200 Watt Kit $29, PCB only $4.95.
AEM 35 Watt Single Chip Audio Power Amp $19.95: this is an ideal amp for the beginner to construct;
uses an LM1875 chip and a few parts on a 1 inch square PCB.
Low Distortion Balanced Line Audio Oscillator Kit $69: designed to pump out line up tone around studio
complexes at 400Hz or any other audio frequency you wish to us. Maximum output +21dBm.
MONO Audio DA Amp Kit, 15 splits: $69.
Universal BALUN Balanced Line Converter Kit $69: converts what you have to what you want, unbalanced
to balanced or vice versa. Adjustable gain. Stereo.
•
•
••
COMPUTERS
•to Max
I/O Card for PCs Kit $169: originally published in Silicon Chip, this is a real low cost way to interface
the outside world from your PC, 7 relays, 8 TTL inputs, ADC & DAC, stepper motor drive/open collector
1 amp outputs. Sample software in basic supplied on disk.
•onlyIBM3 chips
PC 8255 24 Line I/O Card Kit $69, PCB $39: described in ETI, this board is easy to construct with
and a double sided plated through hole PCB. Any of the 24 lines can be used as an input or
output. Good value.
•• Professional
19" Rack Mount PC Case: $999.
All-In-One 486SLC-33 CPU Board $799: includes dual serial, games, printer floppy & IDE hard disk drive
interface, up to 4Mb RAM 1/2 size card.
•PC104
PC104 486SLC CPU Board with 2Mb RAM included: 2 serial, printer, floppy & IDE hard disk $999; VGA
card $399.
KIT WARRANTY – CHECK THIS OUT!!!
If your kit does not work, provided good workmanship has been applied in assembly and all original parts
have been correctly assembled, we will repair your kit FREE if returned within 14 days of purchase. Your
only cost is postage both ways. Now, that’s a WARRANTY!
KITS-R-US sell the entire range of designs by Graham Dicker. The designer has not extended his agreement
with the previous distributor, PC Computers, in Adelaide. All products can be purchased with Visa/Bankcard
by phone and shipped overnight via Australia EXPRESS POST for $6.80 per order. You can speak to the
designer Mon-Fri direct from 6-7pm or place orders 24 hours a day on: PH 018 80 6794; FAX 08 270 3175.
92 Silicon Chip
Beyer claim the MPC 22 and 23
produce higher gain before feedback
than typical boundary microphone
designs. The MPC 22’s semi-cardioid
response makes it suitable for multiple microphone installations while
its integral low-cut filter eliminates
low frequency rumble and unwanted
surface-bound noise. The MPC 23’s
half-spherical polar pattern offers a
uniform pickup pattern and is ideal
in single microphone installations.
Both models feature an M20 x 1.5
threaded body with mating nut for
direct installation into material to a
maximum thickness of 57mm and are
supplied complete with elastic bearing
rings for mechanical isolation from
the mounting surface. Termination of
the microphones is via a male 3-pin
XLR connector fitted in its base. Both
models may be run with universal
8-52VDC phantom powering.
Beyer MPC 22/23 microphones are
available in white or black finish and
have a recommended retail price of
$375.00.
For further information, contact
Amber Technology, Unit B, 5 Skyline
Place, Frenchs Forest 2086. Phone (02)
9975 1211; fax (02) 9975 1368.
Flatbed printer has automatic
head gap adjustment
The new C-650 flat
bed printer from C.
Itoh is able to identify
the thick
n ess of the
paper being used and
adjust the print head
gap automatically, providing consistent print
quality on all types of
stationery. Friction feed and push tractors provide
accurate feeding of both cut sheet and continuous
paper. Unusual paper thickness (from 0.05-2mm)
and different sizes can be handled.
The C-650 paper feed is suited to special stationery such as multiple forms, labels, prescriptions and passbooks, and is capable of handling
stationery sizes ranging from cheque cards to A4
landscape. Paper path handling is straight-through
under software control or by 1-key touch operation.
Both Centronics parallel and RS232 serial interfaces are standard and an optional serial interface
with current loop and RS422 is also available, as is
an auto sheet feeder.
For further information, contact Anitech, 52/2
Railway Parade, Lidcombe, NSW 2141. Phone (02)
749 1244.
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