Iron Age Audioworks EQ H9 User manual
©2019 by IronAgeAudioworks
Mic Preamp / EQ H9
©2021 by IronAgeAudioworks 1
Thank you for your purchase of an Iron Age H9 500 series module. Iron Age Audioworks is a
small team of engineers and designers and we truly appreciate your business. We hope you
enjoy using this as much as we enjoyed making it.
Safety
Safety with audio equipment is normally a matter of common sense, but we want to make sure
you get the best use out of your equipment. So please, use common sense including...
●Use typical practices for using electrical and audio equipment.
●
●Any ventilation openings in the case need to remain open.
●
● or use a ground-lift device that does.
●
stepped on.
●
Power
The unit is powered by the 500 series chassis it is mounted in, and uses an onboard voltage
regulator. It complies with VPR standards.
©2021 by IronAgeAudioworks 2
Overview
The Iron Age 500 series H9 module was designed as a tribute to famous British consoles of the
early 70s. The mic preamp and EQ combine for an instantly recognizable character, and are all
around useful tools in tracking or mixdown.
Each H9 features a discrete class A mic pre that offers 0 to 70 dB of gain in 10 dB steps. In mic
mode the signal starts with a Jensen input transformer. In line, a true-to-history unbalanced
input is available at +10, 0 and -10 dB gain. The preamp stage feeds a discrete high pass filter
set for 80Hz, followed by the classic three band passive EQ. A second gain stage acts as
makeup gain for the EQ, and a discrete class A buffer drives the line out. 48V phantom power
is available in mic mode only.
As with all Iron Age products, the H9 is as discrete as possible, designed and made in the USA.
Block Diagram
©2021 by IronAgeAudioworks 3
Controls
The GAIN knob adjusts the gain of the preamplifier. In the first
three positions, it is in line input mode, which bypasses the mic
input transformer and engages a pad. Line mode also
disconnects phantom power from the input. In the final seven
modes, the net gain is adjusted to the amount indicated. A pad is
automatically engaged in the first two positions.
The +48 switch provides phantom power to the microphone. This
only works in mic gain points.
The HPF switch engages an active 80 Hz high pass filter.
The EQ switch engages the passive EQ.
The high band is shelf, where each step adjusts the frequency
response at 10 kHz by 2 dB from -10 to +10.
The mid band is an inductor peaking band with eleven selectable
frequencies. The cut or boost function of the mid band is set by
the boost/cut switch. The amount of gain or cut is set by the gain
knob. Fully clockwise is +15 dB, counterclockwise is 0 dB. A
feature of the passive inductor EQ is that the cut behavior is
narrower than the boost.
The low band switch has two functions. Counterclockwise from
center a 50 Hz shelf is engaged in 3 dB increments up to -15 dB.
Clockwise from center selects the boost frequency and engages
the boost control knob. The boost control knob can be rotated to
a fully clockwise position to turn the low frequency band off. This
ensures a flat frequency response.
©2021 by IronAgeAudioworks 4
Inputs and Outputs
The input uses a Jensen mic input transformer to receive a nominal -66 dBu balanced input in
mic mode or +4 dBu in line mode via the 500 series pinout.
The output is a nominal +4 dBu impedance balanced line output via the 500 series pinout.
Chassis
The Iron Age H9 is a VPR compliant 500 series module.
©2021 by IronAgeAudioworks 5
Technical Specifications
Gain Range
Mic 0 - 70 dB
Line -10 - +10 dB
Maximum Input Level
Mic -2.5 dBu
Line +25 dBu
Maximum Output Level +15 dBu
Input Impedance
Mic 1500 Ohms, transformer balanced
Line 10 kOhms, unbalanced
Output Impedance 47 Ohms, impedance balanced
Frequency Response +/- 1 dB 20Hz-20kHz
Actual Measured Noise better than -90 dBA
THD @ +15 dBu output <1%
Power Consumption <120 mA
©2021 by IronAgeAudioworks 6
Warranty
We warrant this product to be free from defects of materials and workmanship for a period of
one (1) year from the date of purchase. We will remedy any defect identified within this period
by repairing or replacing the product at our option. It will be your responsibility to pay for
shipping the product to us, and if the product is determined to be defective, our responsibility to
pay for shipping the product back to you.
LIMITATIONS AND EXCLUSIONS. This warranty, and any other express or implied warranty,
does not apply to any product which has been improperly installed, subjected to usage for which
the product was not designed, misused or abused, damaged during shipping, or which has been
altered or modified in any way. This warranty is extended to the original purchaser only. THIS
EXPRESS, LIMITED WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR
IMPLIED, TO THE EXTENT ALLOWED UNDER APPLICABLE STATE LAW. IN NO EVENT
SHALL IRON AGE AUDIOWORKS BE LIABLE FOR ANY SPECIAL, INCIDENTAL, OR
CONSEQUENTIAL DAMAGES RESULTING FROM THE USE OF THIS PRODUCT.
If you suspect a defect in this product, please contact us to discuss the problem (it is possible
that a suspected defect could be quickly remedied or due to improper usage).
want you to love it too.
contact@ironageaudioworks.com
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