Hafler HA75 User Manual

HA75

Tube Head
Headphone Amp

User Guide

Haer is a division of Radial Engineering Ltd.
1588 Kebet Way, Port Coquitlam
BC, Canada V3C 5M5
[phone] info@haer.com

www.haer.com

HA75 'TUBE HEAD' HEADPHONE AMP

USER GUIDE

Table of Contents Page

Overview ................................................................................ 1

Features ................................................................................. 2

Connect .................................................................................. 4

Testing Your Connections ....................................................... 6

AB Switch ............................................................................... 6

Feedback Control ................................................................... 7

Understanding the Focus Control ........................................... 8

Understanding the VOX Control ............................................. 9

Warranty .................................................................Back Cover

Thank you for purchasing the Haer HA75 Tube Head. This
warm sounding tube headphone amplier is designed to be

easy to use while providing the user with many customizable
features to further enhance enjoyment. This manual has been
written in order to provide you with all of the details so that you
may take full advantage of these extra features. As such, we

ask that you take a few minutes to read it. If you nd yourself
looking for more information, please visit the HA75 FAQ page on
the Haer web site. This is where we post answers to questions

from users that are often helpful. Then, if you are still missing

something, feel free to send us an email at info@haer.com and

we will do our best to reply in short order.

CAUTION

HIGH VOLTAGE

There are high voltages inside the HA75. Before opening the unit - It

must be unplugged from the power supply and allowed to discharge
for at least 30 minutes. Touching the wrong place can cause a severe
shock. High voltages present at the tube socket will remain present for

some time after switching the HA75 off. There are no user serviceable

parts inside. Only use indoors in a dry space. Do not open unless you

are a qualied technician or have experience with tubes.

OVERVIEW

The Haer HA75 uses a 12AX7 tube as part of the signal amplication.

Tubes are preferred by audio enthusiasts and recording engineers for

their smooth, natural sound. The HA75 tube sound will reduce ear fatigue
compared to typical solid-state counterparts.

The HA75 is also able to generate tons of power. Unfortunately, this

opens the door to potential risks that you must be aware of. The high

output tube amplier is intended for use by recording professionals to

enable them to monitor dynamics without constraint when using a wide

range of headphones of varying impedances. This means that non-

professional home users must take special care to prevent excessive
exposure over a long period of time. You should therefore consult your
local health authority for details on allowable exposure limits in order to
prevent damage to your hearing. This is particularly important when using

ear-buds as these are designed to accommodate low output ampliers,

which means they can be very loud with very little output power.

WARNING

HIGH POWER AMPLIFIER

The powerful amplier inside the HA75 is designed to accommodate
all types of headphones from 8Ω to 400Ω. As we have no way of
determining the headphone impedance, the amplier is very loud.

Exposure to high sound pressure levels for an extended period of
time can cause irreparable ear damage. Please consult your local
health authority to ensure you do not expose yourself beyond
recommended limits. Radial shall not be held responsible for

using the HA75 without due care or beyond recommended legal

limits imposed by your local government. Use by children is not
recommended and therefore must be carefully monitored by parents
or guardians.

Haer

HA75 'TUBE HEAD' HEADPHONE AMP

1

FEATURES

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1. ON: Activates the HA75. It is recommended to warm up the tube for
15 minutes to achieve thermal stability.

2. SELECT: From the front panel you can select between two different
inputs designated as A (balanced/unbalanced) and B (unbalanced).

3. FEEDBACK: Controls the amount of negative feedback that is
being introduced back into the circuit.

4. GAIN: Used to adjust the volume for headphones.

5. FOCUS: Active matrix lets you control the width of the stereo image

to replicate listening to loudspeakers in a room.

6. VOX: Three position switch lets you enhance low
frequencies to suit the listening level and program material.

7. HEADPHONE OUTPUTS: Dual ¼” TRS outputs to enjoy the
listening experience with a friend or client. For best results use two
matched headphones as the impedance determines the loudness.

VOX Switch
A - Bass enhancer
Ø - Bypass / O
B - Loudness

Haer

HA75 'TUBE HEAD' HEADPHONE AMP

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