Mark Levinson 20-6 Owners Manual

Operating Manual

Mark Levinson

Nº20.6

Monaural Reference Amplifier

Madrigal Audio Laboratories, Inc.

Important safety instructions

Read all instructions and precautions carefully and completely before operating your Nº20.6 Monaural Reference Amplifier.

1. ALWAYS disconnect your entire system from the AC mains before connecting or disconnecting

any cables, or when cleaning any component.

2. This product is equipped with a three-conductor AC mains power cord which includes an earth

ground connection. To prevent shock hazard, all three connections must ALWAYS be used. If your electrical outlets will not accept this type of plug, an adapter may be purchased. If an adapter is necessary, be sure it is an approved type and is used properly, supplying an earth ground. If you are not sure of the integrity of your home electrical system, contact a licensed electrician for assistance.

3. AC extension cords are not recommended for use with this product. If an extension cord must be used, be sure it is an approved type and has sufficient current-carrying capacity to power this product.

4. NEVER use flammable or combustible chemicals for cleaning audio components.

5. NEVER operate this product with any covers removed.

6. NEVER wet the inside of this product with any liquid.

7. NEVER pour or spill liquids directly onto this unit.

8. NEVER block air flow through ventilation slots or heatsinks.

9. NEVER bypass any fuse.

10. NEVER replace any fuse with a value or type other than those specified.

11. NEVER attempt to repair this product. If a problem occurs, contact your Mark Levinson® dealer.

12. NEVER expose this product to extremely high or low temperatures.

13. NEVER operate this product in an explosive atmosphere.

14. ALWAYS keep electrical equipment out of the reach of children.

Thank you for choosing the Mark Levinson® Nº20.6 Monaural Reference Amplifier.

A great deal of effort went into the design and construction of this precision device. Used properly, it will give you many years of enjoyment.

Table of contents

Unpacking and placement .......................................................................1

Unpacking .............................................................................................. 1

Placement ............................................................................................. 1

Ventilation ..............................................................................................1

Custom installations .............................................................................. 1

Voltage selection ........................................................................................ 2

Figure 1: Rear panel .......................................................................

Signal connection .......................................................................................3

Connectors ............................................................................................ 3

Cables .................................................................................................... 3

Connection methods and operating modes .................................... 3

Single-ended normal (non-inverting) operation ............................... 3

Figure 2: Connections for single-ended normal (non-inverting)

operation ..................................................................................

Single-ended inverting operation ....................................................... 4

Figure 3: Connections for single-ended inverting operation .....

Balanced normal (non-inverting) operation...................................... 4

Figure 4: Female input connector ................................................

Figure 5: Connections for balanced normal (non-inverting)

operation ..................................................................................

Speaker connections .................................................................................6

Assembling the speaker connectors .................................................. 6

Figure 6: Line-mount speaker connector assembly....................

Connecting the speakers ..................................................................... 7

Chassis ground ...................................................................................... 7

Power connection ....................................................................................... 8

Connecting the AC power cord ......................................................... 8

Figure 7: AC power cord polarity .................................................

Performance tips ................................................................................... 8

Protection circuitry ................................................................................ 8

Bridged operation .......................................................................................9

Connections for balanced bridged operation ................................. 9

Figure 8: Connections for balanced bridged operation ...........

Figure 9: Balanced bridging cable .............................................

Connections for single-ended bridged operation .......................... 10

Figure 10: Connections for single-ended bridged operation..

Care and Maintenance............................................................................12

Cleaning ............................................................................................... 12

Fuses...................................................................................................... 12

Specifications ............................................................................................13

Dimensions.................................................................................................14

Figure 11A: Dimensions, Nº20.6, top view ..................................

Figure 11B: Dimensions, Nº20.6, side view ..................................

14 14

Unpacking and placement

Unpacking

Placement

Ventilation

Unpack your Nº20.6 Monaural Reference Amplifier and keep all packing materials for future transport. Because of the weight of the unit, handles are provided front and rear so two people may lift and carry the amplifier comfortably and without risk of injury.

Carefully inspect the product for damage and flaws. If you discover any, contact your Mark Levinson dealer immediately.

To get the best performance from the Nº20.6, speaker cables should be as short as possible. Place the Nº20.6 as close to the loudspeakers as is practical.

Place the Nº20.6 at least three feet away from the turntable and preamplifier; otherwise, the Nº20.6 may induce hum in these sensitive components.

The Nº20.6 may be placed in a cabinet or on a shelf, but adequate ventilation must be provided to prevent overheating. The clearance provided by the unit’s feet must be maintained to ensure unrestricted air flow through the heatsinks and vents in the bottom of the chassis. (Placing the Nº20.6 on carpeting, for example, may prevent adequate ventilation.) Clearance above the unit must also be maintained to allow air circulation and to prevent heat buildup.

The Nº20.6 incorporates thermal sensors located near each group of output devices. If the heatsink temperature becomes excessive, these sensors will shut off the amplifier before damage results. After a brief cooling period, the amplifier can be reactivated via the front panel switch. If this occurs regularly during normal use, it's an indication that the ventilation provided for the amplifier is inadequate. If there's adequate ventilation and the problem continues, see your Mark Levinson dealer immediately.

Custom installations

PRECAUTION

This product doesn't comply with EIA rack-mount standards. A 19" rack-mountable front plate is available from your Mark Levinson dealer.

For custom installations and cabinetry, this information may be helpful:

■ All temperature measurements are made at the top of the

heatsink, 3.5" behind the front plate.

■ Normal heatsink temperature at idle after warmup, with unrestricted airflow at 22°C (72°F) ambient temperature: 44°C (111.2°F).

■ Maximum permissible heatsink temperature before thermal protection is activated: 80°C (176°F).

To facilitate special installations and custom cabinetry, drawings are included in this manual (see “Dimensions”).

For your protection, review “Important safety instructions” before you install your Nº20.6.

Figure 1: Rear panel

Voltage selection

The Nº20.6 can be internally set for 100V, 120V, 200V, 220V, or 240VAC mains operation. Make sure that the label on the rear panel indicates the correct AC operating voltage for your location.

Voltage

indication

Nº20.6 MONAURAL REFERENCE AMPLIFIER

OPERATING

VOLTAGE:

• 90 - 110 VAC~

• 105 - 125 VAC~

• 180 - 220 VAC~

• 210 - 240 VAC~

• 230 - 250 VAC~

• ~47-400 Hz

WARNING:

HAZARDOUS VOLTAGES AVAILABLE INSIDE: DISCONNECT AC~ MAINS CABLE BEFORE REMOVING ANY COVERS. HIGH ENERGY AVAILABLE AT LOAD TERMINALS. REFER TO OWNER'S MANUAL FOR PROPER TERMINATION INSTRUCTIONS. DISCONNECT AMPLIFIER FROM AC~ MAINS BEFORE REPLACING FUSES. MAINS FUSES:

AC mains fuses

• E

•

AC mains

connector

DESIGNED AND MANUFACTURED IN U.S.A. BY

MADRIGAL AUDIO LABORATORIES, INC.

Output

•

–+

–

SERIAL NO.

Balanced

–+

OUTPUT

BALANCED INPUT

–

INPUTS

Chassis ground binding post

PUSH

input

PRECAUTION

Single-ended inputs

If the voltage indicated is incorrect, see your Mark Levinson dealer.

If you wish to change the AC operating voltage of your Nº20.6, contact your Mark Levinson dealer.

A pair of Nº20.6 amplifiers may be powered by a 15-ampere AC mains line. For optimum performance into lower impedance loads, however, it's recommended that the AC mains outlets used for the Nº20.6 be capable of supplying a minimum of 15A @ 100V or 120VAC, and 7.5A @ 200V, 220V, or 240VAC

per amplifier

. If other devices are also powered from the same AC circuit, their additional power consumption must be considered.

Two slow-blow 250V 3AG fuses (10A @ 100V or 120VAC, and 5A @ 200V, 220V, or 240VAC) are located on the rear panel of the Nº20.6. Replace the fuses with the same type only.

ALWAYS remove the AC cord before removing the fuses.

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