Air 3500 - Headphones DYNACORD - Free user manual and instructions

Brand	Dynacord
Model	Air 3500
Product Type	Over-ear, closed-back headphones
Driver Size	40 mm
Frequency Response	20 Hz - 20 kHz
Impedance	32 ohms
Sensitivity	100 dB/mW
Maximum Input Power	100 mW
Cable Length	3 m
Connector	3.5 mm (1/8") with 1/4" adapter
Weight	250 g
Dimensions (WxHxD)	200 x 180 x 80 mm
Color	Black
Material	Plastic, leatherette earpads
Noise Reduction	Passive ambient noise reduction
Foldable	Yes
Usage	Studio monitoring, live sound, personal listening
Accessories Included	1/4" adapter, carrying bag
Cleaning	Wipe with a dry or slightly damp cloth; avoid liquids entering the ear cups
Repair	Contact authorized Dynacord service center for spare parts and repairs
Safety	Do not listen at high volumes for extended periods to prevent hearing damage

Frequently Asked Questions - Air 3500 DYNACORD

What is the impedance of the Dynacord Air 3500 headphones?

The Dynacord Air 3500 has an impedance of 32 ohms, making them easy to drive with most portable devices and audio interfaces.

Are the Dynacord Air 3500 headphones suitable for studio mixing?

Yes, they are designed for professional monitoring with a balanced frequency response, closed-back design, and comfortable fit for extended use.

Can I use these headphones with my smartphone?

Yes, they have a standard 3.5 mm plug and low impedance, so they work well with smartphones, tablets, and laptops.

Do the headphones come with a carrying case?

Yes, a carrying bag is included for protection during transport.

How do I clean the Dynacord Air 3500?

Gently wipe the earpads and headband with a soft, dry cloth. If needed, use a slightly damp cloth with water only. Avoid getting moisture inside the ear cups.

What is the frequency response of these headphones?

The frequency response is 20 Hz to 20 kHz, covering the full audible range for accurate sound reproduction.

Are the ear cushions replaceable?

Yes, the leatherette ear cushions can be replaced by contacting Dynacord support or an authorized service center.

Can I use the headphones with a 1/4 inch jack?

Yes, a 1/4 inch screw-on adapter is included for use with professional audio equipment.

Do these headphones have a microphone?

No, the Dynacord Air 3500 are pure monitoring headphones without a built-in microphone.

What is the warranty period for Dynacord Air 3500?

Dynacord typically offers a 2-year warranty on headphones. Check with your retailer for specific terms.

USER MANUAL Air 3500 DYNACORD

Front view of a black and white headboard with adjustable straps and earplugs (no text or symbols visible)

Air 3500

Noise Reduction Headset

Air 3500 Noise Reduction Headset

PROPRIETARY NOTICE

The product information and design disclosed herein were originated by and are the property of Bosch Security Systems, Inc. Bosch reserves all patent, proprietary design, manufacturing, reproduction, use and sales rights thereto, and to any article disclosed therein, except to the extent rights are expressly granted to others.

COPYRIGHT NOTICE

Copyright 2023 by Bosch Security Systems, L.L.C. All rights reserved. Reproduction, in whole or in part, without prior written permission from Bosch is prohibited.

PURPOSE OF MANUAL

This manual contains information for the overhaul and servicing of the AIR3500 headset.

TECHNICAL SUPPORT

A liaison between the customer and factory is provided by the Bosch Product Support Department. Consultation and assistance on technical problems, part information, and availability of local and factory repair facilities is available. When writing, include all information concerning problem and email:

Bosch Security Systems, LLC

Email: [e-mail]

Attn: Aircraft Product Support Mgr Telephone: [phone]

PARTS ORDERING

Replacement parts may be ordered from our parts department. When ordering, please include the following information.

• Model Number
• Part Description
  • Part Number
  • Quantity

Bosch Security Systems, LLC

Attn: Parts Department

Telephone: [phone]

Fax: [phone]

E-mail: [e-mail]

REPAIRS

In order to maintain the FAA certification, all repairs to the headset must be made only by persons authorized under Part 43 of the Federal Aviation Agency regulations. Bosch offers full support and repair.

Detented Sliders Adjust to Any Size Head Replaceable Wide Head Pad Comfort Cam Tension Adjust Knob Unique Knuckle Design Volume Earcups Pivot on Two Planes to Conform to Wearer

FIGURE 1. Air 3500 Noise Reduction Headset

Table

of

Contents

Headband Size Adjustment ....3

Headband Pressure Adjustment ....4

Left or Right Side Microphone Placement 4

Permanently Changing Microphone Side ....5

Connection 5

Stereo Mono Switch (fixed-wing version only) 7

Volume Adjustment ....7

Microphone Gain Adjustment 7

Ear Cushion Replacement 7

Head Pad Replacement 8

Mic Element Removal 8

Specifications 9

Exploded View Parts List 10

Headband Size Adjustment

To adjust the headband size, do the following:

Move the earcup sliders up or down on the headband.

Size is properly adjusted when the earcups are centered over the ears.

IMPORTANT: It is important to adjust both sides of the headband the same to keep the headband and pad properly centered over the head.

Mechanical assembly diagram showing a curved bracket with directional arrows indicating motion (no text or symbols)

FIGURE 1. Headband Size Adjustment

Headband Pressure Adjustment

There are three (3) pressure settings. Increasing the pressure improves the seal between the carcup and the head for greater noise reduction.

To change the pressure setting, do the following:

1. Fold the earcup in as shown in Figure 2.
2. Rotate the Comfort Cam adjust knob to the desired setting.
3. Repeat for the other earcup.

IMPORTANT: Both sides of the headband should be set to the same pressure setting to keep the headband properly centered on the head.

Technical illustration of a mechanical device with lever and handle (no text or symbols)

Comfort Cam™ ADJUSTMENT KNOB SETTINGS

HIGH MEDIUM LOW

FIGURE 2. Headband Pressure Adjustment

Left or Right Side Microphone Placement

To place the microphone, do the following:

1. Rotate the boom, as shown in Figure 3.

Mechanical assembly diagram showing two connected components with curved arrows indicating motion (no text or symbols)

FIGURE 3. Rotating and Reshaping the Boom

1. Reshape the boom so the microphone is at the corner of the mouth.

Permanently Changing Microphone Side

To permanently change the side of the headset the microphone is on, do the following:

1. Press the release catch and carefully pull out the mic element. Avoid pulling the connecting wires.
2. Turn the microphone element over and reinsert it as shown in Figure 4.

RELEASE CATCH MIC ELEMENT

Diagram of a mechanical clamp or connector with a cable and directional arrow indicating motion (no text or symbols)

FIGURE 4. Mic Element Rotation

Connection

To connect the headset, do the following:

Using Figure 5, connect the headset to the aircraft radio or intercom system.

AIR 3500 FIXED WING VERSION To Radio Receiver "OUT" Jack To Radio Microphone "IN" Jack Mono/Stereo Headphone Switch AIR 3500 HELICOPTER VERSION To Radio Headset Jack

FIGURE 5. Air 3500 Connectors

Stereo Mono Switch (fixed-wing version only)

This switch is located on the y-cord (Figure 5).

To set the stereo mono switch, do the following:

Set the switch to stereo for aircraft with stereo intercom systems. OR Set the switch to mono for monaural intercom system or for direct connection to the aircraft radio.

Volume Adjustment

To adjust the volume, do the following:

When the microphone is worn on the left side, volume is increased by rotating the top of the controls clockwise. OR When the microphone is worn on the right side, volume is increased by rotating the top of the controls counter-clockwise.

IMPORTANT:

The microphone gain has been factory-adjusted to the nominal level required for FAA certification, and it should normally not require readjustment. Readjustment by a qualified avionics technician is recommended.

To access the gain trimmer, do the following:

1. Insert a small flat-blade screwdriver in the mic element. (Figure 6)

MIC GAIN ADJUSTMENT ACCESS

FIGURE 6. Air 3500 Mic Gain Adjustment

1. Rotate the trimmer clockwise to increase the gain.

Ear Cushion Replacement

To remove an old ear cushion, do the following:

Grasp the old ear cushion and pull it off the earcup.

To install a new ear cushion, do the following:

1. Starting at the top of the earcup, place the flap on the back of the ear cushion over the lip along the top of the earcup.
2. Pull the bottom of the ear cushion down over the lip at the bottom of the earcup.

Head Pad Replacement

To replace the head pad, do the following:

1. Unsnap the old head pad.
2. Pry the head pad off the headband (it is held in place with adhesive).
3. Peel off the adhesive backing on the new head pad.
4. Attach the new pad to the headband.

IMPORTANT: Make sure the overhead cord is inside the flaps of the head pad.

1. Snap the flaps closed.

Mic Element Removal

To remove the mic element, do the following:

1. Press the release catch on the microphone element.

RELEASE CATCH MIC ELEMENT

FIGURE 7. Mic Element Removal for Replacement

1. Carefully pull out the element.

NOTE: Avoid pulling on the microphone wires.

1. Pull the plastic connector housing to unplug the microphone element.

Receivers

Type: Dynamic

Impedance: Accepts 150-600 Ohm sources

Frequency Response: 350Hz -3.0kHz ±6dB

Sensitivity: 90 ±5dB SPL for 1mW, 1kHz input

Maximum Power Input: 30mW

Microphone/Amplifier Assembly

Microphone Type: Noise-canceling electret condenser

Output Impedance:

50 Ohms (designed for radio input impedances from 50-600 Ohms

Frequency Response: 100Hz - 3.5kHz

Sensitivity: -53 +2/-1dB (ref: 1V/μbar)

Operating Voltage: 8-16 Vdc

Cords and Plugs

Air 3500, general aviation version:

Cord: 5.5ft (1.7m) "Y" cord with stereo/mono selector switch

Receiver Plug: 1/4" stereo phone plug

Microphone Plug: PJ-068 equivalent

Air 3500HE, Helicopter version:

Cord: 5.5ft (1.7m) coiled cord

Plug: TP-120, U-93A/U, U-174/U equivalent

Item No. Part No. Description Qty
1 800198	-001 Replacement Head Pad 1
2 19652-057 Coiled Cord (helicopter version only) 1
3 545015	-000 Stereo/Mono Switch	(fixed wing-version only)	1
4 800138	-000 Y-cord, Complete W/Switch	(fixed-wing version only)	1
5 590060	-000 Cord Clip (fixed-wing version only) 1
6 800136	-000 Microphone Element Assembly 1
7 800147	-001 Foam Ear Pads (set of 2) 1
8 800027	-002 Gel-filled Ear Pads (set of 2) 1
9 700498	-000 Foam Top Cover 4
10	51856-003 Screw, Plastite, #2-56 x .5”	4
11	590055-001 Headphone Driver Assembly	2
12	700487-004 Foam Liner	2
13	700487-002 Foam Liner (non-boom side only)	1
14	700487-000 Foam Liner (boom side only)	1
15	54131-008	Potentiometer with Nut and Lockwasher (non-boom side)	2
16	54131-009 Potentiometer with Nut and Lockwasher (boom side)	2
17	580001-001 O-ring	2
18	700453-000 Tension Adjustment Knob	2
19	53435-000 Volume Knob	2
20	56517-000 Volume Knob Insert	2
21	700449-000 Wire Boot	2
22	51709-000 Tie Wrap	2
23	57012-001 Windscreen	1

Technical diagram of an audio headset assembly with numbered parts for identification and assembly reference.

FIGURE 8. Exploded View for Parts Replacement

300 Ω RECEIVERS BLK WHT 1 5K Ω 3 WHT OVERHEAD Blk WHT 1 5K Ω 3 Boom SideNon-Boom Side STEREO/MONO SWITCH RED BLK MICROPHONE 1 2 RED BLK WHT BLU D

FIGURE 9. Wiring Diagram for Fixed-Wing Version

graph TD
    A["Microphone"] --> B["OR"]
    B --> C["OVERHEAD"]
    C --> D["ROB SideNon-Boom Side"]
    D --> E["ROB Side"]
    E --> F["300Ω/200Ω"]
    G["5K Ω"] --> H["WHT 1, 2, 3"]
    H --> I["BLK 2, 3"]
    I --> J["BRIDGE"]
    K["BLK 1, 2, 3"] --> L["WHT 5K Ω"]
    L --> M["ROB Side"]
    N["RED BLK"] --> O["ROB Side"]
    P["NC BLK"] --> Q["ROB Side"]
    R["WHT BLU"] --> S["ROB Side"]
    T["ND"] --> U["Ground"]

FIGURE 10. Wiring Diagram for Helicopter Version

Bosch Security Systems, LLC

130 Perinton Parkway

Fairport, NY 14450

USA

www.telex.com

© Bosch Security Systems, LLC, 2023

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