Heritage Audio HA-609A User manual

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HA-609A QUICK START GUIDE
This is a quick start guide on using the HA-609A dual compressor/limiter unit.
For more info on it or more tips on how to use the unit, please check
www.heritageaudio.net often, and make sure to follow Heritage Audio on
Facebook, Instagram and You Tube.
Dec 2nd, 2019
Rev. 1.0.

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INSTALLING THE HA-609A
Thanks for purchasing the HA-609A stereo dual mono compressor/limiter.
Please make sure the following items are in the box when you open it.
• This manual.
• HA-609A main unit.
• 48v Power Supply.
• IEC Cable.
Depending on your system requirements, you will need four XLR cables to
hook up your system. Please check your input sources and output
destinations and purchase the correct cables.
The power supply is of the auto switching type so it works worldwide without
adjusting anything. In case your country uses a different mains cable other
than the one provided in the box, just get the correct one and you are done.
Basic audio connections are just balanced left and right input and output
connections by means of XLR connectors. Should you require to connect the
unit to unbalanced equipment, please do so by connecting pin 3 to ground.
The HA-609A is able to accept input levels in excess of those that any
interface can provide, so the chance that its input is overloaded is rare.
However, it is able to provide output levels in excess of those that most
interfaces can accept, so please keep this in mind.

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GENERAL DESCRIPTION
The Heritage Audio HA-609A DUAL MONO STEREO COMPRESSOR/LIMITER is
a professional diode bridge-based dynamics processor in a convenient 2RU
format. It features Carnhill/St Ives transformer balanced inputs and outputs,
and the outputs are driven by means of ´73 type Class A amplifiers. It also
features St. Ives interstage transformers to isolate the diode bridges in a fully
floating configuration. Therefore, there is a total of no less than 6 Carnhill/St
Ives transformers per unit, 3 per channel and tone for days.
Unlike vintage diode bridge designs, the HA-609A has dual attack times both
in the compressor and limiter sections and expanded threshold and limit
level ranges that easily accommodate the hotter modern input signals. Gone
is the classic problem of the unit always compressing even at the highest limit
level and compression threshold that used to drive crazy to the mixing and
mastering engineers.
Finally, the all discrete class A construction departs from other vintage and
current diode bridge units, (which still rely on class A/B amps), and reacts so
much better to compression, in a much more musical way.

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CONNECTION FEATURES
The HA-609A has the following connections:
• INPUT L: Transformer balanced, accessible on an XLR connector.
• INPUT R: Exactly as Input L.
• OUPUT L: Transformer balanced, ´73 type class A amp driven,
accessible on an XLR connector.
• OUTPUT R: Exactly as Output L
• POWER: Connects the external power supply by means of a barrel
type pin.
GETTING STARTED WITH THE UNIT
Once you have made the right connections for your application, please
POWER ON your unit and PRESS BOTH BYPASS buttons to make sure the
compressor is not activated. They are of the true bypass type, so audio
should pass directly from input connectors to output connectors and meter
lights should remain off. To start with, the slow attack and an AUTO release
setting are good options for both compression and limiting. Turn Threshold
to maximum and press COMPRESS IN. Set RATIO to 2:1. Fun begins.
The meter´s light should turn ON to advise that dynamics are working. Turn
Threshold control counter clock wise until you get the desired amount of
compression. Recover lost gain with the gain makeup control and you´re
done!

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For the limiting section, a similar approach should be made. Please keep in
mind that both compression and limiting sections actuate so the one making
the highest gain reduction at a given instant takes over. Please also keep in
mind that gain makeup is PRE-limiting section, therefore increasing gain
makeup with limiter ON will make the unit limit earlier and levels over the
limit one will not be possible.
AN APPROACH TO USING THE HA-609A
Using the HA-609A in the manner explained above will give you instant
gratification, however the unit is far more powerful.
Playing around with ATTACK and RELEASE settings will change the sound by A
LOT. Fast attack and releases will eat up transients more and may make your
sounds less punchy but thicker and more detailed at the same time, with
ambience and sustained passages being more noticeable. The best way to
learn is experiment!
LIST OF CONTROLS
The list of controls, from left to right, is as follows:
• LIMIT LEVEL: Sets the output level at which limiting occurs. Range is
from 0 to +20dBu on a high quality stepped potentiometer.
• LIMIT RELEASE TIME: On a 6-position rotary switch. From fast 50
milliseconds to 0.8 seconds and 2 automatic release times (fast on
peaks, slow on sustained program).
• LIMIT ATTACK TIME: 2 different times on a push button. Fast is with
button pressed.

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• LIMIT IN: Activates the limiting section. If audio level is below the set
limit level, it does not actuate. If it exceeds the limit level, it is limited
at the limit level.
• COMPRESSION THRESHOLD: With an extended range from +20dBu
(all clockwise) to -20dBu (all counterclockwise) on a stepped
precision potentiometer.
• RATIO: From a very gentle 1.5:1 to a hard 6:1. On a 5-position rotary
switch.
• COMPRESSION RELEASE: On a 6-position rotary switch. From
medium-fast 100 milliseconds to pretty slow 1.5 seconds and 2
automatic release times (fast on peaks, slow on sustained program).
• GAIN MAKEUP: Allows for restoring the gain loss up to 2dB steps, on
a 41-step precision potentiometer.
• COMPRESSION ATTACK TIME: 2 different times on a push button.
Fast is with button pressed.
• COMPRESS IN: Activates the compression section. If audio level is
below threshold level, it does not actuate. If it exceeds the threshold
level, it is attenuated as per the ratio law.
• BYPASS 1 and 2: Of the true bypass, relay-based type, they
effectively bypass the whole unit.
• GAIN REDUCTION METER 1 and 2: Measures gain reduction in dB.
They are respectively illuminated when their BYPASS buttons are
disengaged.
• LINK: Engages the stereo mode. When both channels are linked, the
same control signal drives both channels. You need to manually
• POWER: Turns power ON.

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TECHNICAL SPECIFICATIONS
• Maximum input level: Over +22 dBu.
• Maximum output level: Over +26.5 dBu into 600 ohms.
• Self-Noise: Less than -75dBu 20Hz-20Khz. -80dBu A-weighted.
• THD+N (50Hz- 20Khz): not engaged, less than 0.07% at +20dBu.
• Frequency response, COMPRESS and LIMIT OUT, +- 0.5dB, 15Hz-
30Khz.
• Input impedance: 10Kohms, transformer balanced and floating.
• Output impedance: Less than 75 ohms, transformer balanced and
floating, Class A driven.
• Compressor characteristics: Threshold from –20 to +20 dBu on a 41-
step precision potentiometer. Ratio selectable on a rotary switch,
1.5:1, 2:1, 3:1, 4:1, 6:1. Release selectable on a rotary switch, 100,
400, 800, 1500 mS, A1 and A2 auto release times. A1 corresponds to
50mS on peaks and around 500mS on sustained program. A2 to 50mS
on peaks and 1.5 seconds on sustained program.
• Limiter characteristics: Limit level selectable from 0 to +20 dBu on a
41-step precision potentiometer. Release selectable on a rotary
switch, 50, 100, 200, 800 mS, A1 and A2 auto release times. A1
corresponds to 50mS on peaks and around 800mS on sustained
program. A2 to 50mS on peaks and 1.5 seconds on sustained
program.

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LIMITED 2 YEAR WARRANTY
Heritage Audio HA-609A is warranted by Heritage Audio SL to be free from
defects in materials and workmanship for the period of 2 years to the original
purchaser. In the event of such defects, the product will be repaired without
charge or, at our option, replaced with a new one if delivered to Heritage
Audio prepaid, together with a copy of the sales slip or other proof of
purchase date. The warranty excludes problems due to normal wear, abuse,
shipping damage or failure to use the product in accordance with the
specifications.
Heritage Audio shall not be liable for damages based upon inconvenience,
loss of use of the product, loss of time, interrupted operation or commercial
loss or any other damages, whether incidental, consequential or otherwise.
This warranty is not transferable.
Heritage Audio and the Heritage Audio “H” logos are registered Trademarks
owned and/or licensed by Heritage Audio.
www.heritageaudio.net
ALFONSO GOMEZ 38. 3C
28037 Madrid
Spain
[e-mail]