Tascam MH-8 User manual

MH-8
Headphone Amplifier
D01098720A
OWNER'S MANUAL
Contents
IMPORTANT SAFETY INSTRUCTIONS........2
1 − Introduction .........................................4
Features ........................................................... 4
Included items................................................. 4
About this manual .......................................... 4
Trademarks...................................................... 4
Precautions and notes for placement
and use ............................................................ 4
Cleaning the unit ............................................ 4
2 − Names and Functions of Parts ............5
Front panel...................................................... 5
Rear panel ....................................................... 6
3 – Troubleshooting ...................................7
4 – Specifications........................................8
Audio inputs and outputs .............................. 8
Audio performance ....................................... 8
Dimensional drawings .................................... 9
Block diagram ............................................... 10
Level diagram................................................ 11

2 TASCAM MH-8
The exclamation point within an equilateral triangle is intended to alert the user to
the presence of important operating and maintenance (servicing) instructions in the
literature accompanying the appliance.
The lightning flash with arrowhead symbol, within equilateral triangle, is intended
to alert the user to the presence of uninsulated “dangerous voltage” within the
product’s enclosure that may be of sufficient magnitude to constitute a risk of
electric shock to persons.
CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE
COVER (OR BACK). NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING
TO QUALIFIED SERVICE PERSONNEL.
WARNING: TO PREVENT FIRE OR
SHOCK HAZARD, DO NOT EXPOSE
THIS APPLIANCE TO RAIN OR
MOISTURE.
This appliance has a serial number located on the rear
panel. Please record the model number and serial
number and retain them for your records.
Model number
Serial number
In North America use only on 120V supply.
CE Marking Information
a) Applicable electromagnetic environment: E4
b) Peak inrush current: 9.124 A
TO THE USER
This equipment has been tested and found to comply
with the limits for a Class A digital device, pursuant to
Part 15 of the FCC Rules. These limits are designed
to provide reasonable protection against harmful
interference when the equipment is operated in a
commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and,
if not installed and used in accordance with the
instruction manual, may cause harmful interference to
radio communications.
Operation of this equipment in a residential area is
likely to cause harmful interference in which case the
user will be required to correct the interference at his
own expense.
CAUTION
Changes or modifications to this equipment not
expressly approved by TEAC CORPORATION for
compliance could void the user's authority to operate
this equipment.
For U.S.A.
IMPORTANT SAFETY INSTRUCTIONS
Norwegian:
Produkter med Klasse I konstruksjon er utstyrt
med en ekstern strømforsyning med en 3-pins
tilkoblingskontakt. Det er viktig at denne kontakten
tilkobles en jordet stikk-kontakt.
Swedish:
Produkter med Klass 1 konstruktion är utrustad
med strömförsörjning med jordad 3 stifts strömad-
apter. Sladdkontakt till denna måste kopplas till en
AC adapter med skyddande jord.
Finnish:
Tuotteen suojausluokka on I (suojamaadoitettu).
Tuote on kytkettävä suojamaadoitettuun pistora-
siaan.

TASCAM MH-8 3
Do not expose this apparatus to drips or splashes.
•
Do not place any objects filled with liquids, such
•
as vases, on the apparatus.
Do not install this apparatus in a confined space
•
such as a book case or similar unit.
The apparatus draws nominal non-operating
•
power from the AC outlet with its POWER or
STANDBY/ON switch not in the ON position.
The apparatus should be located close enough
•
to the AC outlet so that you can easily grasp the
power cord plug at any time.
The mains plug is used as the disconnect device,
•
the di sc onne ct device sha ll remain readily
operable.
Products with Class I construction are equipped
•
with a power supply cord that has a 3-prong
grounding plug. The cord of such a product must
be plugged into an AC outlet that has a protective
grounding connection.
If the product uses batteries (including a battery
•
pack or installed batteries), they should not be
exposed to sunshine, fire or excessive heat.
CAUTION for products that use replaceable lithium
•
batteries: there is danger of explosion if a battery
is replaced with an incorrect type of battery.
Replace only with the same or equivalent type.
Caution should be taken when using earphones or
•
headphones with the product because excessive
sound pressure (volume) from earphones or head-
phones can cause hearing loss.
If you are experiencing problems with this product,
•
contact TEAC for a service referral. Do not use the
product until it has been repaired.
RACK-MOUNTING THE UNIT
ª
Use the supplied rack-mounting kit to mount the unit in a
standard 19-inch rack, as shown below.
Remove the feet of the unit before mounting.
NOTE
Leave 1U of space above the unit for ventilation.
•
Allow at least 10 cm (4 in) at the rear of the unit for
•
ventilation.
1 Read these instructions.
2 Keep these instructions.
3 Heed all warnings.
4 Follow all instructions.
5 Do not use this apparatus near water.
6 Clean only with dry cloth.
7 Do not block any ventilation openings. Install in
accordance with the manufacturer's instructions.
8 Do not install near any heat sources such
as radiators, heat registers, stoves, or other
apparatus (including amplifiers) that produce
heat.
9 Do not defeat the safety purpose of the polarized
or grounding-type plug. A polarized plug has two
blades with one wider than the other. A grounding
type plug has two blades and a third grounding
prong. The wide blade or the third prong are
provided for your safety. If the provided plug does
not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.
10 Protect the power cord from being walked on
or pinched particularly at plugs, convenience
receptacles, and the point where they exit from
the apparatus.
11 Only use attachments/accessories specified by
the manufacturer.
12 Use only with the cart, stand, tripod, bracket, or
table specified by the manufacturer, or sold with
the apparatus. When a cart is used, use caution
when moving the cart/apparatus combination to
avoid injury from tip-over.
13 Unplug this apparatus during lightning storms or
when unused for long periods of time.
14 Refer all servicing to qualified service personnel.
Servicing is required when the apparatus has
been damaged in any way, such as power-supply
cord or plug is damaged, liquid has been spilled
or objects have fallen into the apparatus, the
apparatus has been exposed to rain or moisture,
does not operate normally, or has been dropped.
IMPORTANT SAFETY INSTRUCTIONS

4 TASCAM MH-8
Thank you for your purchase of the TASCAM MH-8
Headphone Amplifier.
Before connecting and using the unit, please take time
to read this manual thoroughly to ensure you understand
how to properly set up and connect the unit, as well as the
operation of its many useful and convenient functions. After
you have finished reading this manual, please keep it in a
safe place for future reference.
You can also download the Owner's Manual from the
TASCAM web site (http://www.tascam.com).
Features
Rack-mountable 1U size
•
8 headphone outputs
•
Maximum output of 250 mW + 250 mW (at 32Ω)
•
2 pairs of inputs
•
INPUT 1 on XLR connectors or TRS phone jack inputs
•
INPUT 2 on XLR connectors or RCA pin jack inputs
•
Each headphone output channel also has direct inputs
•
Every input and output channel has an overload indica-
•
tor and a signal indicator
Ground lift switch allows signal grounding to be turned
•
ON or OFF for all channels at the same time
Included items
The included items are listed below.
Take care when opening the package not to damage the
items. Keep the package materials for transportation in the
future.
Please contact the store where you purchased this unit if
any of these items are missing or have been damaged dur-
ing transportation.
Main unit (MH-8)
•............................................................1
Power cord
•.......................................................................1
A rack-mounting screw kit
•..............................................1
A warranty card
•..............................................................1
Owner's manual (this manual)
•........................................1
About this manual
In this manual, we use the following conventions:
The names of keys and controls are given in the follow-
•
ing typeface: POWER.
Additional information is introduced in the styles below
•
when needed:
1 − Introduction
NOTE
Explanation of actions in special situation and
supplement.
CAUTION
Instructions that should be followed to avoid injury,
damage to the unit or other equipment.
Trademarks
TASCAM is a trademark of TEAC Corporation, regis-
•
tered in the U.S. and other countries.
Other company names, product names and logos in this•
document are the trademarks or registered trademarks of
their respective owners.
Precautions and notes for placement
and use
The operating temperature should be between 5°C and
•
35°C (41°F and 95°F).
Make sure that the unit is mounted in a level position for
•
correct operation.
Do not place any object on the unit for heat dissipation.
•
Avoid installing this unit on top of any heat-generating
•
electrical device such as a power amplifier.
Cleaning the unit
To clean the unit, wipe it gently with a soft dry cloth. Do
not wipe with chemical cleaning cloths, benzene, paint
thinner, ethyl alcohol or other chemical agents to clean the
unit as they could damage the surface.

TASCAM MH-8 5
POWER switch and indicator

Press to turn power ON or OFF. The indicator lights
when the power is ON.
Overload (OL) indicators

These light if the level input to this device is too high
(overloading with a clipping level of –3 dB or higher).
Signal (SIG) indicators

These light when a signal (–20 dBu or greater) is
detected at an input jack.
Input LEVEL knobs

Use to adjust the input levels.
INPUT 1 and 2 activation buttons

Select which of the two inputs (INPUT 1 or 2) to output
to the headphones.
Overload (OL) indicators

These light if the level input to the channel is too high
(overloading with a clipping level of –3 dB or higher).
Signal (SIG) indicators

These light when a signal (–20 dBu or greater) is
detected at a direct input for the channel.
DIR buttons

Press to output the signal from the corresponding
DIRECT INPUTS to the headphones.
MONO buttons

Make the headphone output function as a monaural
output.
PHONES jacks
Connect headphones.
PHONES knobs
Adjust the headphones output levels.
Front panel
2 − Names and Functions of Parts

6 TASCAM MH-8
Rear panel
DIRECT INPUT jacks
These direct input connectors provide direct line inputs
for each channel.
FOLDBACK output connectors
These output the input signals (INPUT 1 and 2)
unchanged.
NOTE
When input is through INPUT 2’s unbalanced RCA pin
jacks, the nominal output level is converted to balanced
+4 dBu.
INPUT 2 XLR connectors
These XLR connectors are balanced line inputs for
INPUT 2.
(1: GND, 2: HOT, 3: COLD)
INPUT 2 RCA jacks
These RCA pin jacks are unbalanced line inputs for
INPUT 2.
NOTE
Signals should not be input to both the XLR and the RCA
connectors at the same time. Use either the XLR or the
RCA connectors for input.
INPUT 1 XLR connectors
These XLR connectors are balanced line inputs for
INPUT 1.
INPUT 1 TRS jacks
These TRS jacks are balanced line inputs for INPUT 1.
NOTE
Signals should not be input to both the XLR and the TRS
connectors at the same time. Use either the XLR or the
TRS connectors for input.
Signal ground (SIGNAL GND) connector
Use a commercially available PVC-covered cord to
connect this connector to the signal ground. Note that
this is NOT an electrical safety ground (earth).
Power connector
Use the included power cord to connect the power
source.
CAUTION
When using this unit, always use the included power
cord. Moreover, do not use the included power cord
with any other equipment. Misuse of a power cord could
cause malfunction, fire or electric shock.
Ground lift (GND LIFT) switch
Even when the ground connector is used to ground the
unit, this ground connection can be interrupted (ground
lift) by setting the GND LIFT switch to the left.
2 − Names and Functions of Parts

TASCAM MH-8 7
If you are having trouble with the operation of this unit,
please try the following before seeking repair. If these
measures do not solve the problem, please contact the store
where you bought the unit or a TASCAM Service Center.
Power will not turn ON.
ª
Confirm that the power plug is securely inserted.
•
No sound is output.
ª
Are the headphones connected correctly?
•
Are the input sources connected correctly?
•
Are the input selections correct?
•
Are the input
•LEVEL knobs minimized?
Are the headphone output (
•PHONES) knobs minimized?
There is noise.
ª
Check the connecting cables for incomplete connec-
•
tions.
3 – Troubleshooting

8 TASCAM MH-8
Audio inputs and outputs
INPUT 1 and 2
Connector XLR-3-31
(1: GND, 2: HOT, 3: COLD)
Input impedance 56 kΩ
Nominal input level +4 dBu (1.23 V)
Maximum input level +24 dBu (12.3 V)
INPUT 1
Connectors 6.3 mm (1/4”) TRS Standard
phone jacks
(Tip: HOT, Ring: COLD, Sleeve:
GND)
Input impedance 56 kΩ
Nominal input level +4 dBu (1.23 V)
Maximum input level +24 dBu (12.3 V)
INPUT 2
Connectors RCA pin jacks
Input impedance 22 kΩ
Nominal input level –10 dBV (0.3 V)
Maximum input level +10 dBV (3.16 V)
DIRECT INPUT
Connectors 6.3 mm (1/4”) TRS Standard
phone jacks
(Tip: HOT, Ring: COLD, Sleeve:
GND)
Input impedance 56 kΩ
Nominal input level +4 dBu (1.23 V)
Maximum input level +24 dBu (12.3 V)
FOLDBACK outputs
Connectors 6.3 mm (1/4”) TRS Standard
phone jacks
(Tip: HOT, Ring: COLD, Sleeve:
GND)
Output impedance 94Ω
Nominal output level +4 dBu (1.23 V)
Maximum output level +24 dBu (12.3 V)
PHONES outputs
Connectors 6.3 mm (1/4”) Standard
stereo phone jacks
Maximum output 250 mW + 250 mW (32Ω)
Audio performance
Frequency response 20 Hz - 50 kHz/100 mW 32Ω,
±3 dB (PHONES outputs)
10 Hz - 100 kHz, ±3 dB
(FOLDBACK outputs)
S/N ratio 85 dB or greater (PHONES
outputs, A-WTD, 20 kHz LPF)
90 dB or greater (FOLDBACK
outputs, A-WTD, 20 kHz LPF)
THD 0.05% or less (PHONES outputs,
when outputting 100 mW + 100
mW (32 Ω), 20Hz HPF and 20
kHz LPF)
0.007% or less (FOLDBACK
outputs, 20 Hz HPF and 20 kHz
LPF)
Channel separation 50 dB or greater (Within a
channel, PHONES outputs,
A-WTD, 20 kHz LPF,1 kHz
nominal input, 32Ω termination)
90 dB or greater (FOLDBACK
outputs, A-WTD, 20 kHz LPF,
1 kHz nominal input, 600Ω
termination)
Crosstalk 65 dB or greater (PHONES
outputs, A-WTD, 20 kHz LPF,
1 kHz nominal input, 32Ω
termination)
Power AC 100-240V, 50-60 Hz
Power consumption 36 W
Dimensions (mm) 482 (width) x 44 (height) x 280
(depth)
Weight 3.8 kg
4 – Specifications

TASCAM MH-8 9
Dimensional drawings
10.5 mm 280 mm 14 mm 31.8 mm
432.6 mm 41.1 mm
0.9 mm
44 mm
434.2 mm
482.6 mm
465 mm
Illustrations and other depictions may differ in part from the actual product.•
Specifications and external appearance may be changed without notification to improve the product.•
4 – Specifications

10 TASCAM MH-8
Block diagram
-2dBu+4dBu
-10dBv -2dBu
MAX +8dBu
MAX +8dBu
+4dBu
-2dBu
INPUTS 2 INPUTS 1 FOLDBACK 1 FOLDBACK 2
GND LIFT
CIRCUIT GROUND CHASSIS GROUND
TRS-L(MONO)
TRS-R
INPUT 1 DIR 1 INPUT 2
DIRECT INPUTS 1
TRS-L(MONO)
TRS-R
INPUT 1 DIR 8 INPUT 2
DIRECT INPUTS 8
. . . . . .
INPUTS 1 L
INPUTS 1 R
INPUTS 2 L
INPUTS 2 R
INPUTS 1 L
INPUTS 1 R
INPUTS 2 L
INPUTS 2 R
DIRECT INPUTS 2 - 7
R L
L
R
XLR - L
TRS-L(MONO)
1/2
U107
TRS - R XLR - R
1/2 1/2 1/2
1/2 1/2
U101
U101
U107
U108
U108
U103
U104
INPUT 1 LED
OL
SIG
1/21/2
COMPARATOR
U105U106
LOGARITHMIC
AMP.
LEVEL - L LEVEL - R
1/2 1/2
INPUT 1 INPUT 1
U102
U102
INPUT 2 LED
OL
SIG
1/21/2
COMPARATOR
U105U106
LOGARITHMIC
AMP.
RCA - L
1/2
U201
1/2 1/2
1/2 1/2
U201 U208
U208
LEVEL - L LEVEL - R
1/2 1/2
INPUT 2 INPUT 2
U203
U203
1/2
U202
RCA - R
1/21/2
U202
U204 U205
1/2
1/2 1/2 1/2
LEVEL - L
PHONES 1
LEVEL - R
OL
SIG
1/21/2
LOGARITHMIC
COMPARATOR
1/2 1/2
1/2 1/2
PHONES 1
PHONES 1
U303
U303
U301
U301
U304
U305
AMP.
Max +22dBu
Max 250mW@32 OHM
LEVEL - L
PHONES 8
LEVEL - R
OL
SIG
1/21/2
LOGARITHMIC
COMPARATOR
1/2 1/2
1/2 1/2
PHONES 8
PHONES 8
U904
U905
AMP.
Max +22dBu
Max 250mW@32 OHM
U003
U003
U001
U001
J101
J102
J103
J104
J105 J106
J204 J205
J303
J001
J301
J302
J003
J002
U302
U302
U002
U002
PHONES 1 LED
PHONES 8 LED
J205
J204
J203
XLR - L XLR - R
. . . . . .
PHONES 2 - 7
4 – Specifications

TASCAM MH-8 11
Level diagram
-2dBu
-2dBu -2dBu
MAX +8dBu
MAX +8dBu
+4dBu
+4dBu
-2dBu
-2dBu
+4dBu
-10dBv
XLR - L TRS - L
INPUT 1 LED
INPUT 1
LEVEL - L
PHONE 1-8
LEVEL - L
FOLDBACK - L
INPUTS1/2
(250mW@32 OHM)
INPUTS 1 XLR (+4dBu)
INPUTS 2 RCA
(-10dBv)
INPUTS 1 TRS INPUTS 2 XLR FOLDBACK 1 FOLDBACK 2
PHONES 1-8
(-2dBu) (-2dBu)
DIRECT INPUT 1-8
INPUTS1/2
DIRECT INPUT 1-8
(+4dBu)
OL SIG
1/2 1/2
COMPARATOR
1/2
U107
(dBv)
+5
0
-5
-10 -20
NOTE: 0dBv=2.218dBu
LEVEL - R LEVEL - L LEVEL - R
INPUT 2 LED
OL SIG
1/2 1/2
COMPARATOR
1/2
U201
1/2
U302/U402/U502/U602
INPUT 2
DIR
LEVEL - R
TRS - R XLR - R
FOLDBACK - R
INPUTS 1
DIRECT INPUTS
1 - 8
RCA - L
XLR - L
FOLDBACK - L
XLR - R RCA - R
FOLDBACK - R
INPUTS 2
OL
SIG
1/21/2
LOGARITHMIC
COMPARATOR
1/2 1/2 1/2
1/2 1/2
1/2 1/2 1/2 1/2
1/2 1/2 1/2 1/2 1/2 1/2
1/2 1/2
1/2 1/2
PHONES 1-8
PHONES 1-8
INPUT 1 INPUT 1
INPUT 2
INPUT 1
U101
U202
U107
U108
U108
U103 U104
U202
U202
U201
U204 U205
U702/U802/U902/U002
U303/U403/U503/U603 U703/U803/U903/U003
U303/U403/U503/U603 U703/U803/U903/U003
U102
U102 U203
U203
U301/U401/U501/U601 U701/U801/U901/U001
U301/U401/U501/U601 U701/U801/U901/U001
U105 U106
U105 U106
U304 U504 U704 U904
U305 U505 U705 U905
AMP.
LOGARITHMIC
AMP.
LOGARITHMIC
AMP.
Max +22dBu
Max 250mW@32 OHM
U206
U206
TRS - R TRS - L
PHONES 1-8 LED
(-8dBu)
(-12dBu)
4 – Specifications

MH-8
TEAC CORPORATION www.tascam.jp
Phone: [phone]
1-47 Ochiai, Tama-shi, Tokyo 206-8530, Japan
TEAC AMERICA, INC. www.tascam.com
Phone: [phone]
7733 Telegraph Road, Montebello, California 90640 USA
TEAC CANADA LTD. www.tascam.com
Phone: [phone] Facsimile: [phone]
5939 Wallace Street, Mississauga, Ontario L4Z 1Z8, Canada
TEAC MEXICO, S.A. de C.V. www.teacmexico.net
Phone: [phone]
Río Churubusco 364, Colonia Del Carmen, Delegación Coyoacán, CP 04100, México DF, México
TEAC UK LIMITED www.tascam.co.uk
Phone: [phone]
Suites 19 & 20, Building 6, Croxley Green Business Park, Hatters Lane, Watford, Hertfordshire, WD18 8TE, UK
TEAC EUROPE GmbH www.tascam.de
Phone: [phone]
Bahnstrasse 12, 65205 Wiesbaden-Erbenheim, Germany
Printed in China