Manley 120 Watt Monoblock Amplifier User manual

MANLEY
LABORATORIES, INC.
OWNER'SMANUAL
MANLEY 120 WATT
MONOBLOCK AMPLIFIER
Manley Laboratories, Inc.
13880 Magnolia Ave.
Chino, CA. 91710
tel: [phone]
fax: [phone]
[email protected]
http://www.manleylabs.com

CONTENTS
INTRODUCTION 3
MAINSCONNECTIONS 4
CONNECTINGYOURAMPLIFIER 5
BIAS PROCEDURES 6
OPERATIONAL NOTES 7
SPECIFICATIONS 8
WARRANTY 9
WARRANTY REGISTRATION 10
SECTION PAGE

THANK YOU!...
for choosing the Manley 120 Watt Monoblock Amplifiers. Designed around the concept that less is
more, the Manley 120 Watt Monoblock Amplifiers very fine components, with the shortest and
cleanest signal path possible, and with the use of our own milling equipment we can provide you
with an amplifier that looks as good as it sounds. We have developed a magnetics winding
department right here at Manley Labs where we design and wind the audio transformers.
Thank you again, and please enjoy!
GENERAL NOTES
LOCATION & VENTILATION
The Manley 120 Watt Monoblock Amplifiers must be installed in a stable location with ample
ventilation. Allow a minimum of 2 inches of clearance on the top and sides of the amplifier, such
that a constant flow of air can flow throughout the ventilation openings. We also recommend that
the amplifier and preamplifier be placed at least 10 inches apart. Do not place amplifiers directly on
high pile carpet or any other surface that will block the ventilation holes.
INTRODUCTION
WATER&MOISTURE
SERVICING
The user should not attempt to service the amplifier beyond that described in the owner's manual.
Refer all servicing other than biasing and tube replacement to Manley Laboratories
SPECIALNOTES
Tubes may become loose during transit. Straighten and press down each tube before plugging the
amplifierintothemainssocket. Furthermore,NEVERtouchthetubesaftertheamplifierhasbeen
switched on, the tubes become very hot during operation and should only be handled after the power
has been turned off and the tubes have cooled.
WARNING!
TO PREVENT THE RISK OF ELECTRIC SHOCK
DO NOT OPEN THE CABINET
REFER SERVICING TO
QUALIFIED PERSONNEL
!

MAINS CONNECTIONS
Your amplifier has been factory set to the correct mains voltage for your country. The voltage
setting is marked on the serial badge, located on the rear panel. Check that this complies with your
local supply.
Exportunitsforcertain markets have a moulded mainsplugfittedto comply with local requirements.
If your unit does not have a plug fitted the colored wires should be connected to the appropriate plug
terminalsinaccordancewiththe followingcode.
GREEN/YELLOW EARTH terminal
BLUE NEUTRAL terminal
BROWN LIVE terminal
As the colors of the wires in the mains lead may not correspond with the colored marking identifying
the terminals in your plug proceed as follows;
The wire which is colored GREEN/YELLOW must be connected to the terminal in the plug which is
marked by the letter E or by the safety earth symbol or colored GREEN or GREEN and YELLOW.
The wire which is colored BLUE must be connected to the terminal in the plug which is marked by
the letter N or colored BLACK.
The wire which is colored BROWN must be connected to the terminal in the plug which is marked
by the letter L or colored RED.
DONOTCONNECT/SWITCHONTHEMAINSSUPPLYUNTILALLOTHERCONNEC-
TIONS HAVE BEEN MADE.

CONNECTING YOUR AMPLIFIER
IMPORTANT: PLUG IN THE TUBES.
We do not ship the amps with the output tubes inserted to prevent breakage. Before plugging
in anything, locate the 2 tubes (KT-90s or 6550s) packed with the amp and insert them in the two
large tube sockets. The sockets are marked 1 and 2, the tubes are marked 1 and 2 - Put 1 in 1 and 2 in
2. This configuration is how the amps were tested and adjusted. Otherwise you will have to re-bias.
You should remove these little labels from the tubes and amp chassis as they are not needed now and
they may bake on permanently if the amp is run for a reasonable amount of time with them on.
Verify that the smaller tubes are sitting straight in their sockets.
Setting up your amplifier is rather easy.
1. Connect all source components (turntable, CD, Tuner, Tape DAT, etc.) to your preampli-
fier. 2. Connect the interconnects from the output of the preamplifier or switching center to the
RCA input on the top rear of the amplifier.
3. Connect the hot or "+" speaker cable to the red binding post and the common or "-"
speaker cable to the black binding post (See diagram 2). Ensure that the other end of the
cable is connected correctly to the speaker. Tighten the binding posts by hand. If you
use a nut-driver (3/8") do not over-tighten the posts or you may breaak the connection
inside the amplifier.
4. Insure that the "mains" switch on the front panel is in the "off" or "0" position.
5. Turn on Preamplifier and any source components you plan to use.
6. Plug amplifier into wall outlet.
7. Turn on the amplifier and allow it to 'warm up' a minute or so before playing any audio
signal.
8. Turn up the volume and enjoy.
You have two amplifier modes - triode and ultralinear. Triode is about half power but is a
less complex audio path which suits some peoples tastes and speakers. Quiet music or
efficient speakers work well in this mode. Damping factor is slightly lower. Ultralinear is
a more common amplifier mode that allows more power, higher damping factor and a
wider range of speakers to be used. Before switching, turn off the amps to prevent
thumps and unwanted noises. Try both - Use the mode that suits you. Best performance
of tube amps is after they are well warmed up, generally about a half hour after powering.
You should get years of use from the tubes. Some statistically last less long and some last for
30 years. Checking bias every month usually will show you if they are drifting and
performing within specification. Excess noise and microphonics, a tube turned white or
not glowing are also big clues a tube needs to be replaced.

BIAS PROCEDURES
The Manley 120 Watt Amplfier uses a variable "fixed bias" system that requires very little attention.
If you wish to adjust or check the bias, complete the following steps. For this procedure you will
need a multimeter to read millivolts (less than 2 volt range) and a small flat screwdriver.
1. Looking at the front section of the top plate of the amplifier, you can see 2 red tip jacks and 1
black tip jack. To measure the current draw of each output tube place the positive probe (red) into
the red tip jack for the tube you wish to measure and the negative probe (black) in the black
(GROUND) tip jack and set the meter to read 'millivolts'.
2. Each of the two (2) output tubes can have its own bias adjusted by altering its own bias adjust
pot. The numbering sequence for the 2 output tubes runs from left to right, as do the corresponding
tip jacks (measurement points). The bias adjust pots are located on the top side of the amplifier,
therefore it will be NOT be necessary to remove the bottom cover to changing the bias. They also
read left to right.
3. The first step to setting the bias is to turn on the amplifier and insure that there is zero signal
input. Mute your preamplifier. Don't play tunes. Also, you MUST leave your loadspeakers
connected as these provide an ideal load on the output. Never operate your amplifiers without a
suitable load or speakers attatched. It is recommended that you leave the amplifier on long enough
to ensure that the tubes have reached their stable current draw.
5. Set your meter to read VOLTS DC. You will be measuring less than 1 volt so set your meter
for a low range if it is not an autoranging meter. Place the probes in the first red tip jack (negative
probes remains in the black tip jack for whole biasing procedure) and adjust the first bias trim pot
located on the left side top deck of the amplifier until you measure approx. 300 mVDC (0.300
VDC). Since you are measuring across a 10 ohm cathode resistor, this would correspond to a 30 mA
bias current. Settings between 275 mV and 300 mV are perfectly OK but try to have each tube the
same.
6. If you are unable to bring the bias voltage down to 300 mV on any tube then we recommend
that the tube be carefully watched or replaced.
7. Follow step five with the other tube. Then go back and recheck again. Check and set the bias
on your amplifiers every day for the first week or any time you retube. Then check every week, then
every month. A red glowing area on the side of the tube usually indicates it is drawing way too much
current. If you see a red spot on the side of the tube, check and reset your bias immediately.

OPERATIONAL NOTES
SWITCHINGON
The power switch is located on the lower left hand corner of the front panel. Push the top of the
rocker switch (1) to turn on the amplifier and the bottom of the rocker to turn off the amplifier. The
LED on the right side of the front panel will illuminate indicating that the amplifier is operating. Do
not turn on and off the amplifier in rapid succession.
RUNNING
It is not recommended that you leave your amplifier permanently switched on. This only wastes
electricityandtubelife. Youramplifierhassolidstaterectificationandreachespeakoperating
conditioninapproximately30minutes.
TUBELIFE
As with all tubes, their quality degrades with age. This is due to cathode emission, a natural process
found in all tubes. We recommend that you have your amplifier checked every 3-4 years, depending
on usage, sometimes the amplifier will require re-tubing after this time has elapsed, although we
have many cases of extreme long life recorded-- 40,000 hours and still counting!.
SPECIAL NOTE
The Manley 120 Watt Monoblocks are equipped with a voltage change-over switch located under
the bottom cover. Insure that this switch is set at 110 if your mains voltage is 100,110,120, or 127
Volts. Set this switch to 220 if your mains voltage is 220, 227, or 240 Volts.
Changing the light bulb:
The lamp which back-lights the Manley insert on the faceplate is a fuse-lamp style lamp. Should it
burn out, turn off and unplug the amplifer from the mains first. Then remove the bottom cover.
Carefully pry out the old lamp from its clips and replace with one of the same type. Although it
looks like a fuse, it is really a light bulb!! Don't put a fuse in there!!
The fuse lamp is 1 1/4" x 1/4" 8Volts, 300mA.
Fuses:
Always replace with same type and rating. Should the B+ fuse blow (the fuse nearer to the output
binding posts) this usually indicates a tube has blown. One should visually inspect the pcb to look
for any burnt resistors a blown tube may have taken out. Also a good test is to measure the resistance
of each catode resistor. This is done in a similar fashion to checking the bias, except do this test with
the amplifier turned OFF, and set your meter for Ohms. Each cathode resistor should measure 10
ohms.

SPECIFICATIONS
Vacuum Tubes: 2 x KT-90 or 6550 (or good KT-88), 1 x 5751, 1 x 7044
Output Power 120 Watts tetrode, 65 triode
Frequency Response, +/- 1 dB 20 Hz - 50 KHz
Input Sensitivity 1 Volt nominal
Input Impedance 100 KOhm
Load Impedance 5 Ohm. Factory preset for 5 Ohm
S/N Ratio @100W -100 dB
Power Consumption 120 Watts Quiescent
360 Watts Full Power
Mains Fuse 100, 110, 120V 4 A (Slo-Blo)
220, 240 V 2 A (Slo-Blo)
Dimensions W=12, D=10, H=6 inches
W=19, D=12, H=6 (panel=3.5) (rack mount version)
Shipping Weight 27 lbs (each)

WARRANTY
AllManleyLaboratories equipment iscoveredbyalimitedwarrantyagainstdefectsinmaterials
andworkmanshipforaperiodof90daysfromdateofpurchasetotheoriginalpurchaseronly.A
furtheroptionallimited5yearwarrantyisavailabletotheoriginalpurchaseruponproper
registrationofownershipwithin30daysofdateoffirstpurchase.
Properregistrationismadebyfillingoutandreturningtothefactorythewarrantycardattachedto
thisgeneralwarrantystatement,alongwithacopyoftheoriginalsalesreceiptasproofofthe
originaldateofpurchase.Only1cardisissuedwitheachunit,andtheserialnumberisalready
recordedonit.
Ifthewarrantyregistrationcardhasalreadybeenremovedthenthisisnotanewunit,andis
thereforenotwarrantedbythefactory.Ifyoubelievethistobeanewunitthenpleasecontactthe
factorywiththedetailsofpurchase.
Thiswarrantyisprovidedbythedealerwheretheunitwaspurchased,andbyManleyLaboratories,
Inc. Underthetermsofthewarrantydefectivepartswillberepairedorreplacedwithoutcharge,
exceptingthecostoftubes.Nowarrantyisofferedontubes,unless:
1. A Manley Laboratories preamplifier is used with a Manley Laboratories amplifier.
2. The warranty registration card is filled out.
Insuchacasea6monthwarrantyontubesisavailablewiththecorrectrecordingoftheserial
numberofthepreamplifieronyourwarrantyregistrationcard.
IfaManleyLaboratories productfailstomeettheabovewarranty,thenthepurchaser'ssole
remedyshallbetoreturntheproducttoManleyLaboratories,wherethedefectwillberepaired
without charge for parts and labor. The product will then be returned via prepaid, insured
freight, method and carrier to be determined solely by Manley Laboratories. All returns to the
factory must be in the original packing, (new packing will be supplied for no charge if needed),
accompanied by a written description of the defect, and must be shipped to Manley
Laboratories via insured freight at the customer's own expense. Charges for unauthorized
service and transportation costs are not reimbursable under this warranty, and all warrantees,
express or implied, become null and void where the product has been damaged by misuse,
accident, neglect, modification, tampering or unauthorized alteration by anyone other than
Manley Laboratories.
Thewarrantorassumesnoliabilityforpropertydamageoranyotherincidentalorconsequental
damagewhatsoeverwhichmayresultfromfailureofthisproduct.Anyandallwarranteesof
merchantabilityandfitnessimpliedbylawarelimitedtothedurationoftheexpressedwarranty.
AllwarranteesapplyonlytoManleyLaboratoriesproductspurchasedandusedintheUSA.
Somestatesdonotallowlimitationsonhowlonganimpliedwarrantylasts,sotheabove
limitationsmaynotapplytoyou.Somestatesdonotallowtheexclusionorlimitationofincidental
orconsequentialdamges,sotheaboveexclusionmaynotapplytoyou.
Thiswarrantygivesyouspecificlegalrightsandyoumayalsohaveotherrightswhichvaryfrom
state to state.

WARRANTYREGISTRATION
We ask that you please fill out this registration form and send the bottom half to:
MANLEY LABORATORIES
REGISTRATION DEPARTMENT
13880 MAGNOLIA AVE.
CHINO CA, 91710
Or you may FAX it to: 909-628-2482
Registration entitles you to product support, full warranty benefits, and notice of product
enhancements and upgrades. You MUST complete and return the following to validate your
warranty and registration. Thank you again for choosing Manley Laboratories.
MODEL ____________________ SERIAL No. ______________________
PURCHASE DATE ______________ SUPPLIER ______________________
--------------------------------------------------------------------------------------------------------
PLEASE DETACH THIS PORTION AND SEND IT TO MANLEY LABORATORIES
MODEL ____________________ SERIAL No. ______________________
PURCHASE DATE ______________ SUPPLIER _______________________
NAME OF OWNER _______________________________________________
ADDRESS ______________________________________________________
CITY,STATE,ZIP________________________________________________
TELEPHONE NUMBER ___________________________________________
Serial #'s of Associated Manley Laboratories Equipment ___________________
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