B&K 7260 series User Manual

600.39 Kb

Reference 7250/7260

series II

Five/Six Channel Amplifier


B & K Components Ltd.

P/N 13007 Rev.0004

B&K Components, Ltd 2100 Old Union Road Buffalo, New York 14227

P/N 13007 Rev.0004

Table of contents

Safety Precautions

page 2

Purpose and function

page 3

Design and construction

page 3


page 3

Rear panel view

page 4

Rear panel description

page 4 - 6

Level controls

page 5


page 5 - 6


page 6

Control Muting

page 8 - 9

System installation

page 7

Making the connection

page 7 - 8


page 10

Care and cleaning

page 10


page 11


page 12

Accessories included: Manual and Power cord


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P/N 13007 Rev.0004




The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user of the presence of uninsulated “dangerous voltage” within the product’s enclosure that may be sufficient magnitude to constitute a risk of electric shock to you.

The exclamation point within an equilateral triangle is intended to alert the user of the presence of important operating and maintenance (servicing) instructions in the literature accompanying the unit.

ŸObservance of polarity is essential. Double-checkconnections before turning the amplifier on. The amplifier can be damaged if polarities are incorrect.

ŸDamage can occur to your speakers if the power rating* of each individual driver is exceeded by the amplifier. Make sure that all the drivers in your speaker system are capable of handling not only the power being delivered by the amplifier, but the energy that is likely to be generated during strong passages.

ŸTurn amplifier ‘off’ before plugging in or unplugging input and speaker cables!!!

ŸThe Reference 7250/7260 series II is equipped with raised feet so that continuous ventilation can be maintained. They help to keep acoustic feedback into the amplifier at a minimum. They also provide a measure of protection against scratching any surface the unit might be resting on. Do not alter or remove them.

ŸDo not stack anything on top of the amplifier (preamplifier, processor, source...etc.).

ŸLeave at least 2-3inches clearance from the top of the amplifier to the next shelf, component, etc., to insure proper ventilation.

*If you are at all unsure of what the speaker ‘ratings’ are, contact your dealer.

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The Reference 7250/7260 series II purpose and function

The Reference 7250/7260 series II is a high current, five/six channel power amplifier. It is designed to be used in all types of audio or audio/video systems.

Design and construction

The Reference 7250/7260 series II utilizes high quality electronic circuitry to achieve an environment wherein a detailed, transparent, and highly musical sound can be realized. The high quality parts complement includes state-of-the-artsolid state devices, 1% metal film resistors, computer grade electrolytic power supply capacitors, and a high capacity toroidal transformer.

The Reference 7250/7260 series II operates class A predriver and AB high current

MOSFET power output stages. It is capable of reproducing the most demanding audio signals at rated power levels.



Toroidal Transformers -

Efficient, high current, shielded transformer.

Discrete Circuitry -

More accurate and three dimensional reproduction of


source material.

Class A Predriver -

Improves low level detail for smoother, more musical



AB MOSFET Output Stage - For efficient linear power delivery and protection from


thermal overload

Gold Plated Connectors -

Improved connections for better sound and minimized


signal loss and degradation.

1% Metal Film Resistors -

Low noise resistors for better sound and a greater


degree of repeatability.

High Current -

Ability to reproduce demanding recordings.

Computer Grade Capacitors - Large capacity computer grade electrolytic capacitors for extended low frequency control and improved dynamics.

Fused Outputs -

Provides protection from accidental shorting of amplifier



Heavy Duty Binding Posts - Improved current carrying capacity and ease of use.

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Rear Panel View
































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































AC fuse holder


Amplifier control muting input/output


AC Input receptacle


Level controls


Speaker outputs

































Speaker fuses

Rear panel description

1. AC fuse holder - Holds the AC Line fuse. This fuse is a 15 Amp / 250 Volt

Slow Blow fuse. Replace with same type and value fuse only.

2.AC Input receptacle - For attaching the supplied AC power cord to the amplifier.

3.Speaker outputs - For connecting the speakers to the amplifier. Explained further

on page 6.

4. Amplifier control muting input/output -

To provide remote switching of mute on/off of the amplifier.

Explained further on pages (8 - 9).

5. Level controls -

For adjusting the input level of each channel into the amplifier.


There are five/six level controls on the back of the amplifier.


One level control for each channel.

6. Inputs -

For connecting signal patch cables (interconnects) from the


preamplifier to the amplifier to pass signal. Pages (5 - 6).

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P/N 13007 Rev.0004

7. Speaker Fuses - Protection against amplifier damage in the case of shorted speaker wires. Replace fuse with same value 6 AMP SLOW BLOW only!


Level controls

When using the level controls, first start with them turned all the way up (clockwise). Then adjust them according to your system requirements to match the sound level coming from each speaker. This is a rough adjustment for matching different driver impedances. Any fine tuning should be done by the preamplifier

Example: When using 4 ohm and 8 ohm speakers together, the 4 ohm may sound louder than the 8 ohm at a given volume level. The level controls on the amplifier are used to match the speakers volume levels. Clockwise will increase the output. Counter Clockwise will decrease the output.


RCA type connectors accept line inputs from the preamplifier’s output connectors. There are five/six input connectors, one for each channel, that may be used to connect the amplifier to the preamplifier.

RCA cable connector

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Here is a typical preamplifier to amplifier setup:


Five way binding posts are provided. One pair for each channel. They are designed to accept a banana-typeplug or spade lug connector (shown below) and are color coded for easy identification. The positive (+) post should always be connected to the speakers (+) jack. The negative(-)post should always be connected to the speakers(-)jack.

Spade connector Banana jack

Here is a typical amplifier output setup:











































































































































































































































































































































































































































































































































































































































































































































































































































































































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System Installation

There will most likely be a number of cables involved in the installation of your home entertainment system. Preplanning is essential in order to maximize system efficiency.

We recommend the following as a means of helping you reach that goal:

§Make a diagram of your proposed system by laying out the relative location of each component in the system. Then lay out the proposed cable runs between them. Number each cable and record its length on the diagram for future reference.

§Cable runs are critical in that they must be kept away from sources of power radiation (amplifiers, power cords, heaters, etc...). For safety reasons, they should also be kept out of traffic areas.

§The process of optimizing the system will include the type of cable, the length of the run, and the obstructions it must deal with along its run. Your dealer can advise you on the products available and their relative merits. If building custom length audio cables is not your strength, your dealer should be able to help you with that as well.

§When possible, use a separate AC power line for the amplifier, one that is not shared by any other household component. Important!

Tip: Take a piece of string (longer than the longest cable run) and mark it at each foot of length. Then do a mock cable run using the string, dressing it neatly along the way. Count the divisions to the next full foot, and add one foot to allow for some movement of the components. This will provide you with the ideal cable length.

Making the connection

§Before doing anything, insure that the power switch on the amplifier’s front panel is in the ‘off’ position.

§Again, it is recommended that you locate a separate AC power outlet for the amplifier, one that is not shared by any other audio component in the system or any other house hold component. This will eliminate the possibility of the amplifier ‘modulating’ the power being supplied to the component and compromising the signal originating from that component.

§Locate the AC power cord provided with the amplifier and plug it into the power input receptacle in the rear panel. Do not connect it to the AC power source yet!

§Connect the audio cables from your preamplifier’s output to the corresponding input connector on the amplifier.

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P/N 13007 Rev.0004

§Connect the wires from your speakers to the appropriate outputs on the amplifier. It is absolutely essential that you observe correct polarity in these connections.

Example: If you connect your left front output of your preamplifier to channel 4 input on the amplifier, remember to connect your left front speaker wires to channel 4's outputs. Always observe polarity when connecting speakers, connect amplifiers (+) to the speakers (+) and amplifiers(-)to speakers(-).

§Double check all connections.

§Connect a playback unit (CD, VLD, Tuner, etc...) to the preamplifier. Turn the volume on the preamplifier to minimum. Turn on the preamplifier, then the amplifier (in that order). Set the source on the preamplifier to the playback unit you’ve just connected. Turn the volume up slowly and listen for music from all channels. If this is not the case, double check your installation.

§Should you encounter any problems that cannot be traced to the source or the material being played, consult the “TROUBLESHOOTING” section on page 10.

Note: When turning equipment ‘off’, the amplifier should always be turned off first, then the preamplifier. When turning equipment ‘on’, the preamplifier should always be turned onfirst, then the amplifier.Before turning anything on, insure the preamplifier is at a low volume level.

Control muting

A control is provided on each Reference 7250/7260 series II amplifier to allow remote switching of mute on/off. The preamplifier’s control output, such as is provided with B&K series preamplifiers, can be utilized to provide a control signal to the Reference 7250/7260 series II. If more than one amplifier is being controlled, the control signal can be extended to include each successive unit by simply running a 1/8" MINI - JACK cable from the CTRL OUT connector of the first amplifier to the CTRL IN connector of the next unit (commonly referred to as ‘daisy chaining’). An example of how to connect two amplifiers is illustrated in figure E.

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If a source other than a B&K series preamplifier is used to control multiple amplifiers, only the control output voltage from the source is critical. It must be within the range, as indicated on the rear panel, 5-24volts DC is required. The amplifier will provide each successive amplifier with a control voltage of 12 volts DC for reliable operation. The amplifiers control output may be used as a source of 12 VDC @ 125 mA for other user applications as well.DO NOT POWER MOTORS WITH THIS CIRCUIT.

If the control function is desired, each unit in the system must remain connected at all times and the control must be enabled. To enable the control function, the CTRL ENABLE button must be out for each controllable amplifier in the system. For more information on the amplifiers output status under various control conditions, refer to the following table.









Button position

Output status





















No Signal



No Signal


No Signal

















* Note: The control voltage is for muting control only. Each amplifier must be connected to its own source of AC power in order for it to operate.

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No sound


Power cord not plugged in


Reconnect power cord

(‘on’ LED not illuminated)


Power off at AC source


Check AC switch or fuse



AC power inlet fuse blown or


Check for shorts or








Control switch in the wrong


Place control switch in





proper position

No sound on some or all


Speaker leads loose or faulty.


Tighten, repair or replace cable

selected channels (‘on’


Line stage to amp cables loose


Tighten, repair or replace cable

LED illuminated


or faulty.





Source to line stage cables


Tighten, repair or replace cable



loose or faulty.





Line stage or source not


Check all switch settings



correctly selected.





Speaker fuse blown


Check all speaker fuses



Level controls adjusted


Re-adjustlevel controls






Sound lacks direction,


Speakers connected out of


Check connections making sure

bass weak




that cables are connected (+)





to (+) and (-)to(-)

Loud hum or buzz on one


Poor ground connection in inter-


Check all connectors and repair

or more channels


connect cables.


as necessary.

Channel sounds distorted


Blown rail fuse


Replace blown rail fuse inside

and low in output





** Note:If unit continues to blow power inlet fuses,DO NOT USE A HEAVIER FUSE!!, have it serviced.

Care and cleaning

Under normal use, the amplifier will not require any special care. Over time you may wish to clean the exterior of the unit by wiping it with a damp cloth to remove any dirt or dust that accumulates on it. Do not let any liquid enter the amplifier through the vents in the top cover. You may clean the connectors on the back panel with isopropyl alcohol annually.

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P/N 13007 Rev.0004

Reference 7250/7260 series II SPECIFICATIONS

Power rating: 8 ohms

200 watts @ 1 kHz

4 ohms

375 watts @ 1 kHz

Frequency response

5 Hz - 45 kHz

Input sensitivity

1.4 Volts


0.09 % @ 1 kHz

Input impedance

33.2 k ohms

Damping factor


Current (peak to peak)

75 Amps

Slew rate

14 V / usec

Dynamic headroom

1.2 dB

S/N (A-weighted)

95 dB

Voltage gain


Line voltage

120/220/240 VAC switchable

Dimensions (O.A.)

17"(w) X 19.25"(d) X 7.25"(h)


70 lb

Power consumption

1830 watts max


17.5 Amps max current draw


130 watts @ no input

Replacement fuses

Line -15Amp/250 Volt Slow Blow


Rails - 6 Amp/250 Volt Slow Blow


Speaker - 6 Amp/250 Volt Slow Blow


In-rush- 2 Amp/250 Volt Slow Blow


Control - .5Amp/250 Volt Fast Blow

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Limited Warranty

B&K Components Ltd., referred to herein as B&K, warrants your B&K equipment against all defects in material and workmanship for a period of five years from the date of purchase. This warranty applies only to the original purchaser and only to equipment in normal residential use and service. Defective equipment must be returned to B&K, prepaid, accompanied by sufficient payment to cover the cost of return shipping and handling, and will be repaired or replaced at the discretion of B&K whose decision as to the method of reparation will be final.

This warranty shall not apply to any equipment which is found to have been improperly installed, incorrectly fused, misused, abused, or subjected to harmful elements, used in any way not in accordance with instructions supplied with the unit, or to have been modified, repaired or altered in any way without the expressed, written consent of B&K. This warranty does not apply to the cabinet, the remote controller, or appearance items such as the faceplate, control buttons, or display lenses, nor does it cover any expenses incurred in shipping the unit to and from the manufacturer’s service depot.

No warranty, implied or otherwise created by State law shall extend beyond the terms of this warranty and B&K shall not be liable for any incidental or consequential damage arising out of a defect in material or workmanship of the unit during the terms of this warranty or thereafter. Some States do not allow the exclusion or limitation of incidental or consequential damages and the foregoing exclusions may not apply to you.

This warranty gives you specific legal rights. Your may also have other rights which vary from State to State.

No agent, representative, dealer or employee of B&K has the authority to increase or alter the obligations or terms of this warranty.

B&K Components Ltd.


No equipment may be returned to B&K Components Ltd. Without a RETURN AUTHORIZATION. Should you find it necessary to return equipment to B&K, for any reason, a RETURN AUTHORIZATION (RA) number must be issued by B&K in respect of the equipment being returned. You may request an RA number by calling B&K at the numbers below. We ask that you provide the following information at that time.

1.Your name, address, and phone number.

2.The model and serial number of the equipment being returned. 3.A description of the problem being experienced.

Your call will be referred to a Technical Service Representative who will work with you to resolve the problem. If it is determined that the unit must be returned for repair, an RA number will be issued.

B&K Components Ltd. 2100 Old Union Road, Buffalo New York 142271-800-543-5252or1-716-656-0023

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P/N 13007 Rev.0004

B&K Components, Ltd 2100 Old Union Road Buffalo, New York 14227

P/N 13007 Rev.0004

B&K Components, Ltd.

2100 Old Union Road

Buffalo, New York 14227


P/N 13007 Rev.0004