Krohn-hite 7600 Operating instructions

Model 7600(M)/7602(M)

Wideband Power Amplifier

DC to 1MHz

141V/282V rms

17/34 Watts

Operating and Maintenance Manual

Service and Warranty

Krohn-Hite Instruments are designed and manufactured in accordance with sound engineering practices

and should give long trouble-free service under normal operating conditions. If your instrument fails to

providesatisfactoryserviceand youare unabletolocate thesourceoftrouble, contactourService Depart-

ment at (508) 580-1660, giving all the information available concerning the failure.

DO NOT return the instrument without our written or verbal authorization to do so. After contacting us,

we will issue a Return Authorization Number which should be referenced on the packing slip and pur-

chase order. In most cases, we will be able to supply you with the information necessary to repair the in-

strument,avoidinganytransportationproblemsandcosts.Whenitbecomesnecessarytoreturntheinstru-

ment to the factory, kindly pack it carefully and ship it to us prepaid.

All Krohn-Hite products are warranted against defective materials and workmanship. This warranty ap-

plies for a period of one year from the date of delivery to the Original Purchaser. Any instrument that is

found within the one year warranty period not to meet these standards, will be repaired or rep laced. This

warrantydoesnotapplytoelectrontubes,fusesorbatteries.Nootherwarrantyisexpressedorimplied.

Krohn-HiteCorporationreserves theright tomake designchanges atany timewithout incurringany obli-

gation to incorporate these changes in instruments previously purchased.

Modificationstothis instrumentmustnot bemade without the writtenconsent of an authorized employee

of Krohn-Hite Corporation.

Model 7600(M) and 7602(M)

Wideband Power Amplifier

DC to 1MHz, 17W and 34W

Serial No. ___________________________

Operating and Maintenance Manual

15 Jonathan Drive, Unit 4

Brockton, MA 02301-5566 U.S.A.

Tel: (508) 580-1660; Fax: (508) 583-8989

Email: [email protected]

Service: ser[email protected]

www.krohn-hite.com

Contents of this publication may not be reproduced in any form

without the written perrmission of Krohn-Hite Corporation.

Printed 5-04, Rev 3.1

Model 7600M ("M" is the Meter Option Package)

Model 7602M ("M" is the Meter Option Package)

Model 7600

Model 7602

Table of Contents

1.0 GENERAL DESCRIPTION ···························1-1

1.1 INTRODUCTION···································1-1

1.1.1 Shipping to Krohn-Hite for Repair or Calibration..........1-1

1.2 SPECIFICATIONS ··································1-1

1.2.1 OUTPUT (All rms values are for sinewave signals).........1-1

1.3 INPUT··········································1-3

1.4 GENERAL ·······································1-3

1.5 OPTIONS········································1-4

2.0 OPERATION ····································2-1

2.1 INTRODUCTION···································2-1

2.2 POWER REQUIREMENTS·····························2-1

2.3 TURN-ON PROCEDURE ······························2-1

2.4 OPERATION······································2-3

2.4.1 Front Panel ..................................2-3

2.4.1.1 PowerSwitch·······························2-3

2.4.1.2 Mode ···································2-3

2.4.1.3 AC/DCCoupling·····························2-3

2.4.1.4 GaindB··································2-4

2.4.1.5 VariableGaindBControl·························2-4

2.4.1.6 DCOffset·································2-4

2.4.1.7 VariableDCOffsetControl························2-4

2.4.1.8 MeterSelectSwitch(MeterOption) ···················2-4

2.4.1.9 Connectors ································2-5

2.4.1.10 OutputDisconnect/ConnectSwitch···················2-5

2.4.1.11 LEDIndicators ·····························2-5

2.4.2 Rear Panel ...................................2-5

2.4.2.1 Option002Connectors··························2-5

2.4.2.2 Chassis/FloatingGroundSwitch ·····················2-5

2.4.2.3 FuseReceptacle ·····························2-6

2.4.2.4 ACPowerReceptacle ··························2-6

2.4.2.5 LineSwitches ······························2-6

3.0 INCOMING ACCEPTANCE···························3-1

3.1 INTRODUCTION···································3-1

3.2 TEST EQUIPMENT REQUIRED ·························3-1

3.3 INCOMING PROCEDURE ·····························3-1

3.3.1 DC Offset and Peak Volts Meter Calibration Check.........3-1

3.3.2 Squarewave Broad Banding Check ...................3-2

3.3.3 Squarewave Rise And Fall Time Check.................3-3

3.3.4 Slew Rate Check ...............................3-3

3.3.5 Gain Calibration Check ..........................3-4

3.3.6 Frequency Response Check ........................3-4

3.3.7 1K Load Maximum Power .........................3-5

3.3.8 Distortion Check...............................3-6

SECTION 1

GENERAL DESCRIPTION

1.1 INTRODUCTION

The Model 7600 and 7602 are 17 watt and 34 wattwideband power amplifiers that offer extended output

power and voltage capabilities, low distortion, versatility and the latest in hybrid CMOS power opera-

tional amplifier technology, with performance features not available in other power amplifiers.

Theunitprovides17wattsofcontinuous power(34wattsatdc)and141Vrmsfromdcto500kHz.Thefre-

quency response is ±0.1dB to 10kHz, and the distortion contributed by the amplifier is <0.01% to 5kHz

and<0.3%to 100kHz.The voltagegain canbe eitherinverting ornon-inverting and hasselectableranges

from0dBto14dB,14dBto 28dBand28dBto42dB(avoltagegainstepof5),andiscontinuouslyvariable

between the ranges.

Otherfeaturesinclude:modesofA,A–Band–B;commonmoderejectionof80dB;inputcouplingof acor

dc; a meterthatis selectableto display heat sink temperatures in °C, outputpeak voltageand average out-

put current. A dc offset control is also provided that is variable from 0V to ±200V.

TheModel7602providesthesamecapabilitiesastheModel7600but alsoprovidesabalanced outputand

isableto deliver 34 watts of continuous power (68 watts at dc), and 282V rms (800V p-p). It can also pro-

vide plus and minus voltages simultaneously.

Claim for Damage in Shipment to Purchaser

The Model 7600 and 7602 are carefully inspected, tested and aged before shipment to ensure that it is

working properly. The unit should be thoroughly inspected immediately upon arrival to purc haser. All

itemsshippedshould bechecked againstthe enclosedpacking list. Krohn-Hitewill not beresponsible for

shortages against the packing list unless notified immediately. If for some reason the instrument is not

workingproperly,orappears tohave beendamaged inshipment,inform thefreight carrierandfilea claim

for the damage, then notify Krohn-Hite or its nearest sales office immediately (to obtaina quotation to re-

pairtheshipmentdamage).Thefinalclaimandnegotiationswiththecarriermustbecompletedbythecus-

tomer.

1.1.1 Shipping to Krohn-Hite for Repair or Calibration

All shipments of Krohn-Hite instruments should be made via United Parcel Service or “Best Way” pre-

paid.The instrumentshould beshippedintheoriginal shippingcontainer; orif notavailable, use any suit-

able container that is rigid and of adequate size. If a substitute container is used, the unit should be

wrapped in paper and surrounded with at least four inches of shock-absorbing material.

Model 7600/7602 Section 1 - General Description

1-1

1.2 SPECIFICATIONS

1.2.1 OUTPUT (All rms values are for sinewave signals)

For the Model 7602, specifications apply to each output to ground.

Frequency Range: dc to 1MHz.

Power

1k Ohm Load: 17W rms, 34W dc and peak, dc to 500kHz; 5W rms to 1MHz.

600 Ohm Load: 10W rms, 100Hz to 1MHz; 5W rms, 10W dc and peak, dc to 100Hz.

Voltage

No Load: ±200V dc and peak, 141V rms.

1k Ohm Load: ±184V dc and peak, 130V rms, dc to 500kHz; ±113V peak, 80V rms at 1MHz.

600OhmLoad:±113Vpeak,80Vrms,100Hzto1MHz;±78Vdcandpeak,55Vrms,dcto100Hz.

Current: 910 ohm load, ±200mA peak, 141mA rms, dc to 500kHz.

Frequency Response: ±0.1dB, dc to 10kHz; ±0.25dB to 200kHz; ±0.5dB to 500kHz, 0-130V rms;

±0.5dB to 1MHz 0-80V rms.

HarmonicDistortion:<0.01%to5kHzand175Vpeakoutput;<0.05%to200Vpeak;<0.3%to100kHz.

Voltage Gain: 0dB to 42dB in three ranges; 0dB to 14dB, 0dB to 28dB, 0dB to 42dB; continuously vari-

able between ranges.

Step Accuracy: ±0.1dB plus frequency response specification. Gain steps are 14dB at max variable

gain control setting or a voltage gain of 5.

Stability: <0.001dB change for a 10% change in line voltage.

Dynamic Range: >80dB.

Hum and Noise (2MHz bandwidth): referred to output, <10mV rms; <20mV rms on the 0dB to 42dB

gain range.

Phase Shift: A input 0° ±1°, B input, 180° ±1° dc to 10kHz increasing linearly 60° lagging at 1MHz.

Model 7602: (Inverted output relative to non-inverted) 180°, –0.3° at 10kHz; 180°, –3° at 100kHz; 180°,

–20° at 1MHz.

Squarewave Response

Rise/Fall Times: 120ns to 50Vp-p.

Slew Rate: >600V/ms, 400Vp-p.

Aberrations: <5%.

Section 1 - General Description Model 7600/7602

1-2

Regulation: <0.1%, No load to 1k ohm load, dc to 10kHz, rising to 2% at 1MHz.

Coupling: DC.

DC Level: Nominal zero volts; vs. temperature, 2mV/°C.

DC Offset Control (no load): 0V to ±200V.

DC Level Stability

Vs. Line: <1mV for a 10% change in line voltage.

Vs. Temperature: <0.01%/°C or 2mV/°C whichever is greater.

Internal Impedance: <0.5 ohms, dc to 10kHz; 5 ohms at 100kHz; 20 ohms at 1MHz.

OutputProtection:Protected from overloads with a uniquefoldbacklimiterwhichkeeps theoutput cur-

rent within safe operating regions. Kickback diodes clamp kickback voltages to the supply.

1.3 INPUT

Modes: A, A–B, –B.

Maximum Voltage (without damage): ±200V dc referred to ground.

Maximum Common Mode: 0dB to 14dB range, ±200V peak; 14dB to 28dB range, ±40V peak; 28dB to

42dB range, ±8V peak.

CommonModeRejection:80dB,dcto200Hz;60dBto1kHz;40dBto10kHz;risingto20dBat1MHz.

Sensitivity: ±1.6V peak.

Coupling: Direct (dc) or capacitive (ac) with low frequency cutoff of approximately 1Hz.

Impedance: 1Megohm inparallel with30pF withfront inputsonly; 65pFwith frontand optional rear in-

puts, independent of input gain setting.

1.4 GENERAL

Load Impedance: Capable of driving any resistive load within the current and voltage limitations of the

amplifiers foldback limiter. Capable of driving reactive loads within voltage and current limitations.

Temperature Range: 0°C to 45°C.

Controls

Front panel:Power switch, 5-position input MODE switch, 2-position INPUT COUPLING switch,

3-position GAIN controlswitch, variableGAIN dBpotentiometer, 10-turnvariable DCOFFS ET po-

tentiometer, 3-position offset RANGE switch, 4-position METER SELECT switch, output CON-

NECT/DISCONNECT switch.

Rear panel: CHASSIS/FLOAT GROUND switch.

Section 1 - General Description

1-3

Front Panel Warning LED Indicators: Over TEMP, CLIPPING, output H.V. (high voltage).

Terminals: BNC A input, BNC B input, binding post output.

Rear Panel: Power receptacle, optional BNC A input, B input and binding post output.

Power Requirements: 90-132/198-264 volts, 50Hz-400Hz, 200 watts.

Dimensionsand Weights: 312“ (9cm) high, 812” (21.8cm) wide, 18" (46ttttttttt.2cm) deep; 12 lbs (5.4kg)

net, 14 lbs (6.3kg) shipping.

Accessories: 3-terminal line cord, operating manual.

1.5 OPTIONS

7600M/7602M Meter - Option Package

HeatSink Temp °C: Measuresthe heatsinktemperaturein thevicinityoftheoutputpoweramplifier

IC. Used as an indicator of operating conditions and air flow to the unit.

Output Peak Voltage: Measures the largest peak voltage independent of polarity with a 1 second

time constant.

Accuracy (at 1kHz): ±0.5V.

Frequency Response: ±2%, 10Hz to 100kHz; 5% to 1MHz.

Average Output Current: Measures average dc supply current delivered to the output amplifier as

an indicator of output amplifier load. Quiescent current is nulled out. Can be used to find resonances

in a load.

Accuracy: ±5% ±1 digit.

Rack Mounting Kit: Part No. RK-37, permits installation of the Models 7600/7602 into a standard 19"

rack spacing.

Option 003: Rear panel input and output connectors.

Section 1 - General Description

1-4

SECTION 2

OPERATION

2.1 INTRODUCTION

This section describes the operation of the Model 7600 and 7602. It includes the proper ac requirements,

the recommended turn-on procedure and a detailed explanation of all the operating controls.

2.2 POWER REQUIREMENTS

TheModel7600 and7602PowerAmplifier is designedtooperatefromasingle-phase, 50Hz to400Hzac

power source of 90 to 110, 108 to 132, 198 to 242 or 216 to 264 volts. The LINE SWITCH located onthe

rearpanel allows the unit to be powered from one of the four voltagerangesabove. Theac powerrecepta-

cleisastandard 3-pinconnectorandcomplieswiththeEuropean I.E.C.standard.Adetachable3-wireline

cord is provided with the unit.

2.3 TURN-ON PROCEDURE

1. Set the LINE SWITCHES for the desired range.

For the 90 to 110 volt range, set the voltage range switch to 120V and the NORM/LOW switch to

LOW.

For the 108 to 132 volt range, set the voltage range switch to 120V and the NORM/LOW switch to

NORM.

For the 198 to 242 volt range, set the voltage range switch to 240V and the NORM/LOW switch to

LOW.

For the 216 to 264 volt range, set the voltage range switch to 240V and the NORM/LOW switch to

NORM.

2. Observe that the POWER switch is in the off position.

3. Toselectthedesired grounding,switch theCHASSIS/FLOATING GROUNDslideswitchlocated on

the rear panel to the proper setting.

WARNING

ThechassisoftheModel7600and7602canbeconnectedtosig-

nalgroundvia theCHASSIS/FLOATING GROUNDswitch. For

safetypurposes,connectthelinecordtoa3-terminalacoutlet.

2-1

Section 2 - Operation

4. Plug the line cord into the unit and then into the ac outlet.

5. Turn the POWER switch on and allow the unit to warm-up for several minutes.

CAUTION

Because of potentially dangerous voltage

within the Model 7600 and 7602, the covers

should not be removed when the unit is con-

nected to an ac outlet, unless it is by qualified

personnel.

The Model 7600 and 7602 is now ready to amplify.

2.4 OPERATION

To operate the Model 7600 and 7602 Power Amplifier, proceed as follows:

1. Make the appropriate power connections ( refer to TURN-ON Procedure).

2. Set the DC OFFSET switch to the OFF position.

3. Set the GAIN dB switch to 0dB.

4. Set the MODE switch to OFF.

5. Set the Input Coupling switch to the desired mode (AC or DC).

6. Set the METER SELECT switch to the PEAK VOLTS position.

7. Connect a voltmeter to the OUTPUT terminals and check for 0V dc.

Allow the unit to warm-up for 30 minutes to obtain rated performance specifications.

CAUTION

The Model 7600 and 7602 is capable of as much as 200V peak

(7600)and 400Vpeak(7602) onitsOUTPUT terminals. To pre-

ventthe possibilityof electricalshock,set theOUTPUTconnect

switchtoDISCONNECTwhenconnectingordisconnecting any

cable or load from the amplifier’s OUTPUT terminals.

2-2

Section 2 - Operation

2.4.1 Front Panel

2.4.1.1 Power Switch

“I” is the ON position, “0” is the OFF position.

2-3

Section 2 - Operation

Figure 2.2 Model 7602M with Meter Option Package

Figure 2.1 Model 7600M with Meter Option Package

2.4.1.2 Mode

The MODE selector switch consists of a 5-position, rotary switch that selects the Mode of operation. The

following are a description of each position:

OFF: When selected, there will be no signal at the OUTPUT terminals.

A: When selected, the input signal will be non-inverted (in-phase) at the (sinewave)

OUTPUT terminal and inverted at the (inverted sinewave)

OUTPUT terminal.

–B: When selected, the input signal will be inverted at the (sinewave) OUTPUT

terminal and non-inverted at the (inverted sinewave) OUTPUT terminal.

A–B: When selected, the output signal will be the mathematical difference between

each input signal.

2.4.1.3 AC/DC Coupling

The AC/DC switch is a 2-position rotary switch with two selectable setting: AC (capacitive coupling) or

DC (direct coupling). In the AC position, the low-cutoff frequency is approximately 1Hz.

2.4.1.4 Gain dB

The GAIN dB switch consists of a 3-position rotary switch with three ranges. A minimum signal of 1.6V

peakmustbeappliedtotheinputinordertoobtain themaximumoutputvoltageof200Vpeak.When used

with the variable GAIN control, each position can be varied as follows:

0dB:0dB to 14dB

14dB::0dB to 28dB

28dB::0dB to 42dB

2.4.1.5 Variable Gain dB Control

The Variable Gain dB Control is a single-turn potentiometer that has an overall gain of 5at each range of

the GAIN dB range switch described in paragraph 2.4.1.2 above.

Note

When the VariableGaindB Controlis inthe maximumCCW position, the am-

plifier’soutput terminalswill stillhaveavoltageorsignal onthem.Inorderto

not have this condition occur, the MODE switch must be set in the OFF posi-

tion, the Output DISCONNECT/CONNECT switch must be set to the DIS-

CONNECT position, or the input signal must be removed.

2.4.1.6 DC Offset

The DC OFFSET switch consists of a 3-position rotary switch with three selectable settings: –200, OFF

and+200.When usedwiththevariableDCOFFSETcontrol,thedcoffsetcanbevariedfrom0Vto –200V

dc and 0V to +200V dc.

2-4

Section 2 - Operation

2.4.1.7 Variable DC Offset Control

The Variable DC OFFSET Control consists of a 10-turn potentiometer that infinitely cont rols the Output

DC Offset 0V to –200V peak or 0V to +200V peak.

2.4.1.8 Meter Select Switch (Meter Option)

The Meter Select Switch is a 4-position rotary switch that allows the LED panel meter to indicate the fol-

lowing:

Heat Sink Temp °C:Indicates the temperature of the heat sink at the output amplifiers.

It gives the user a monitoring device when the amplifier is in an

environment that is not well ventilated.

Peak Volts:Indicates the output peak voltage.

Average (I) +Supply:Indicates the average current of the plus supply.

Average (I) –Supply:Indicates the average current of the minus supply.

2.4.1.9 Connectors

BNCconnectorsareprovidedfortheInputsignal,andBindingPostsareprovidedfortheOutputsignal.

A Input BNC: Sensitivity is 1.6V peak. A signal of ±1.6V peak is needed to achieve maximum output.

Active when the MODE switch is selected to the A or A–B positions.

B Input BNC: Sensitivity is 1.6V peak. A signal of ±1.6V peak is needed to achieve maximum output.

Active when the MODE switch is selected to the –B or A–B positions.

2.4.1.10 Output Disconnect/ Connect Switch

“I” is the ON position, “0” is the OFF position.

2.4.1.11 LED Indicators

Temp: Indicates the heat sink temperature has exceeded 57°C (with Meter option Package only).

Clipping:Indicates when the output is beginning or actually clipping.

>15V: Indicates when the output voltage is >15V (with Meter Option Package only).

2-5

Section 2 - Operation

2.4.2 Rear Panel

2.4.2.1 Option 002 Connectors

BNCconnectorsareprovidedfortheInputsignal,andBindingPostsareprovidedfortheOutputsignal.

2.4.2.2 Chassis/Floating Ground Switch

TheCHASSIS/FLOATING GROUNDswitch isa2-position slideswitchthatdisconnectsthe amplif ier’s

signal ground from its chassis ground when used in the FLOATING mode.

2.4.2.3 Fuse Receptacle

The amplifier’s fuse rating is a 3A slow-blow for both 120V and 230V operation.

2.4.2.4 AC Power Receptacle

The AC power receptacle is a standard 3-wire AC connector.

2.4.2.5 Line Switches

A description of the AC line switches are in paragraph 2.3.

2-6

Section 2 - Operation

Figure 2.1Rear Panel Panel

SECTION 3

INCOMING ACCEPTANCE

3.1 INTRODUCTION

Thefollowing procedureshould beusedtoverifythat theModel7600 and7602isoperatingwithin speci-

fications., both for incoming inspection and routine servicing. Tests should be made with the covers in

place, and the procedure given below should be followed in sequence.

3.2 TEST EQUIPMENT REQUIRED

a. DC volt meter capable of measuring 1mV to 200V with 0.1% accuracy at 200V. Fluke Model 8010A

or equivalent.

b. AC Voltmeter capable of measuring 100mV to 150V rms with a 1MHz bandwidth. Fluke Model

8920A rms volt meter or equivalent.

c. Dual Channel Oscilloscope with X10 probes and a 50MHz bandwidth. Tektronix Model 2245A or

equivalent.

d. 1000 ohm dummy load capable of dissipating 40 Watts.

e. Sinewave source from 10Hz to 1MHz. Krohn-Hite Model 4200B/4300B or equivalent.

f. Sinewave source with <0.01% distortion at 1kHz. Krohn-Hite Model 4400A or equivalent.

g. Squarewave source from 1kHz to 200kHz with 40ns rise and fall time and 5% aberrations.

Krohn-Hite Model 4300 or equivalent.

h. Distortion analyzer that can measure down to 0.005%. Krohn-Hite Model 6900B or equivalent.

In the following procedure the main output is marked with a sinewave and the inverted output is marked

with an inverted sinewave on the front panel.

3.3 INCOMING PROCEDURE

3.3.1 DC Offset and Peak Volts Meter Calibration Check

Set the MODE to OFF.

Set METER SELECT to PEAK VOLTS.

Connect the DVM to the main output.

Set the DC OFFSET control to +200 position.

Adjust the offset control pot for a +199.0V reading on the DVM.

3-1

Section 3 - Incoming Acceptance

The 7600/7602 meter should read 199.0V ±0.5V.

For the 7602 measure the inverted output for –199.0V ±0.4V.

Set the DC OFFSET to –200 position.

Adjust the offset control pot for a –199.0V reading on the DVM.

The 7600/7602 meter should read 199.0V ±0.5V.

The High Voltage LED should be lit and the CLIPPING LED out for both polarities of output offset.

Reduce the DC offset using the offset control pot until the HV LED goes out.

The voltage it goes out at should be 12V to 15V.

Disconnect the DVM from the 7600/7602.

3.3.2 Squarewave Broad Banding Check

The CLIPPING LED should not come on during steps 2 and 3.

Connect a 1kHz, 2.0V p-p (1.0V peak) squarewave to the A and B inputs.

Set the oscilloscope gain for 0.5V/cm with probes on both channels.

Connectbothoscilloscope channelsone andtwo throughX10 probes(probe mustbe broadbanded) tothe

input signal and adjust them to give an optimum matched waveform.

Connect oscilloscope channel two to the main output.

Set scope gain on channel two to 10V/cm, DC coupled.

Set the 7600/7602 for AC coupling and a gain of 28dB (GAIN dB to 28, gain pot to 0 end stop),

MODE to A.

The waveform on the oscilloscope should be 50V p-p (5 cm).

Waveformaberrationssuchasdroop,slantorovershootshouldbelessthan2.5Vor0.25cm.Adjusttheos-

cilloscopevariable gaincontrol knobso thatthe outputamplitude displayed matches the inputamplitude.