ISP Technologies Hum Extractor + Decimator G

Line frequency hum has heavy harmonic content above the line frequency, which occurs at every
interval of the line frequency. The Decimator technology has provided excellent ability to eliminate
this for high gain applications by attenuating the output signal when the guitar notes decay but even
the Decimator cannot remove the hum components that occur at clean or low gain settings since
there is no masking of the noise at these settings. Once there is a guitar signal, the Decimator will
come up to unity gain and at lower gain settings the hum will become audible. As all players know,
the severity of the hum varies from venue to venue but it can destroy an otherwise great
performance when severe. No other option exists that can offer the transparency to eliminate the
hum while preserving the tone and sonic quality of the original signal. The HUM EXTRACTOR does
the impossible and removes the hum without altering the tone of the instrument.

The position of the HUM EXTRACTOR can be selected to operate in either Channel 1 or Channel 2
based on the users preference and rig configuration. The HUM EXTRACTOR + DECIMATOR G is a high
performance two channel DSP processor with three noise reduction operations in one unit. The
HUM EXTRACTOR, typically in channel 1, is inserted between the guitar output and the input of the
guitar rig. Channel 2 is then inserted after the gain or preamplifier in the rig and provides Decimator
Noise reduction with the newest patent pending Decimator X technology for the ultimate adaptive
release. The Decimator level detection is derived from the direct guitar input signal after removal of
the hum components providing perfect tracking of the Decimator functions without the hum
components. This allows greater precision for the Decimator to remove gain noise and gain hiss.

The DSP based Decimator also includes a third noise reduction function, high frequency sliding
filtering, which is found in our high performance ProRack G rack-mount processors. The sliding filter
tracks the high frequency content in the input signal and will adaptively operate to eliminate high

frequency noise from the output signal. The HUM EXTRACTOR + DECMIATOR is dynamic in operation
with a separate threshold level adjustment for both HUM EXTRACTOR and DECIMATOR Noise
Reduction. Once the threshold of the Decimator is set, the user selects the FILTER TRACKING button
to adjust the relative operating point for the Dynamic Filter via the Decimator Threshold control.
Once set, the Decimator threshold will then adjust both the Threshold of the Decimator downward
expander and the Dynamic High Frequency sliding filter. The Dynamic sliding filter will open to allow
the high frequency content in the input signal but will adaptively track this HF content and
effectively eliminate high frequency HISS even when playing low frequency bass notes. The
combined operation of HUM EXTRACTOR, Decimator Downward Expansion and Decimator Adaptive
Sliding Filtering offer a level of real time noise reduction never before available. High quality A/D and
D/A converters along with 32 bit floating point DSP processing means state of the art signal path
audio quality if provided with zero digital aliasing.

Features

• HUM EXTRACTOR + DECIMATOR with zero digital aliasing
• DECIMATOR downward Expander plus DECIMATOR DYNAMIC FILTERING both with
• DECIMATOR X technology
• HUM EXTRACTOR with totally transparent operation
• 2 Channel system allows DECIMATOR to be inserted after gain noise with direct guitar tracking
• Selectable location for HUM EXTRACTOR block
• State of the art signal processing with super low noise signal path
• 50Hz / 60Hz operation
• Greater that 80dB effective noise reduction

Specs
INPUT IMPEDANCE : 470K OHM
INPUT LEVEL TRIM : 21.5db / input level -8dbu to +13.5dbu
MAXIMUM INPUT SIGNAL : +13.5dbu
NOISE FLOOR : - 104dbu A WTD
DYNAMIC RANGE : 117db A WTD
DECIMATOR / MAX NOISE RED : 80db
FREQUENCY RESPONSE : 20Hz – 20KHz = +0 / -.5db
OUTPUTS : Max Level +13.5dbu
DIMENSIONS : 7.15” W x 1.85” H x 4.5” D
WEIGHT : 1.2 lbs

POWER : 9VAC RMS / 1.5 AMPS
NOTE:0dbu = .775 VRMS