Apex Digital AHK1 Quick Start Manual

AHK1
Hum due to ground loops is a common occurrence in pro audio systems. The Apex
AHK1 Hum Killer transformer-isolates any two AC-powered devices' line-level inputs
(or outputs) from the AC ground reference that the devices have established (and thus
defeats the loop). The AHK1 is a passive device requiring neither batteries nor connec-
tion to the AC power.
Connect the AHK1 between any two line-level devices encountering ground loop hum.
For example:
1. Between the output of a synthesizer and the input of a mixer or keyboard amp.
2. Between the line output of an instrument amp and the mixer input.
3. Between the Send jack on an external effects unit (EQ, compressor / limiter etc)
and the Return jack on the mixer or instrument amp.
4. Use both channels to isolate stereo L / R outputs from stereo L / R inputs, or alter-
natively you may isolate one or two mono patches with the AHK1.
5. When connecting the AHK1, run a balanced (or unbalanced) patch cord from
the *line-level output of one device to INPUT 1 on the AHK1, then another from
OUTPUT 1, to the input of the next device or amplifier (i.e. always connect bal-
anced patch cables to the AHK1's OUTPUT jacks).
* DO NOT connect an AHK1 to the speaker output of any amplifier.
Frequency Response:
www.apexelectronics.com

Specifications

10 Hz – 50 kHz, +/- 0.5dB @ +4 dBu
THD: 0.01% Typical @ 1 kHz, +18 dBu,
<0.05% @ 100 Hz, +24 dBu
Insertion Loss: 0.4dB @ 100k ohm Load, 5.5dB
@ 600 ohm Load
Connections: ¼-inch TRS balanced / unbalanced jacks
(114 mm x 73 mm x 38 mm)
Weight: 0.9 lbs (0.4 kg)
Printed in China
mo-AHK1-1v1.pdf