Manley Labs Stereo Receiver MONOBLOCK AMPLIFIER User Manual

MANLEY  
LABORATORIES, INC.  
OWNER'SMANUAL  
MANLEY 250 / 100 WATT  
MONOBLOCK AMPLIFIER  
MANLEY LABORATORIES, INC.  
13880 MAGNOLIA AVE.  
CHINO, CA. 91710  
TEL: (909) 627-4256  
FAX: (909) 628-2482  
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INTRODUCTION  
THANK YOU!...  
for choosing the Manley 250/100 Monoblock Amplifiers. Designed by David Manley, the Manley 250/100  
Monoblock Amplifiers use only the best available components, with the shortest and cleanest signal path possible,  
and with the use of our own in-house CNC machine shop we can provide you with a amplifier that looks as good  
as it sounds.  
The circuit and the components used have been chosen carefully after years of development and refinement for  
reliability, constancy and most importanly, musical, accurate, and emotional delivery of the sound. The circuit  
topology is similar to other designs in the MANLEY range. This amplifier is configured to switch between triode  
or tetrode operation which allows the user to choose between the sonic benefits and seductive qualities of triode  
and the more powerful tetrode operation mode. We emphasize big, beefy reservoir capacitors in the high voltage  
supplies giving plenty of instant energy for dynamic performance of transient peaks and bass performance which  
often exceeds that of rival solid-state amplifiers. We run high voltages on the plates of the output tubes and are  
thus able to run them at lower current which will result in longer life for the output tubes, and careful use of the  
'EVER-WARM' power switching should also greatly increase the life of the output tubes as well as allowing your  
amplifiers to always be ready for pleasurable listening. Each output tube has its own bias adjust, and the  
procedure for adjusting each tube's current draw is described in this manual. The output transformer is a  
revolutionary new design by David Manley which is wound on the Manley Labs factory premesis. Its stellar  
performance will be obvious upon first listening. The secret is in keeping both phases of the push-pull halves  
always equal, and in this new output transformer design, David has achieved just that. The output transformer has  
been factory set for an optimum 5 ohm load which will drive most speakers.  
Thank you again, and please enjoy!  
GENERAL NOTES  
LOCATION & VENTILATION  
The Manley 250/100 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 amplifiers, such that a constant flow of air can  
flow. Do not place amplifiers directly on high pile carpet or any other surface that will block the ventilation  
vents underneath the amplifiers. If you have small children or pets, you should consider placing the amplifiers out  
of reach to prevent damage to the amplifier or damage to your small children or pets by the amplifier as the tubes  
do get hot during operation.  
WATER & MOISTURE  
As with any electrical equipment, these amplifiers should not be used near water or moisture. If liquid enters the  
amplifier, it must be immediately returned to your dealer for servicing.  
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  
SPECIAL NOTES  
Tubes may become loose during transit. Straighten and press down each tube before plugging the amplifier into  
the mains socket. Furthermore, do not touch the tubes after the amplifier has been switched on, as 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 PERSONEL  
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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.  
Export units for certain markets have a moulded mains plug fitted to comply with local  
requirements. If your unit does not have a plug fitted the coloured wires should be connected  
to the appropriate plug terminals in accordance with the following code.  
GREEN/YELLOW  
BLUE  
BROWN  
EARTH  
NEUTRAL terminal  
LIVE terminal  
terminal  
As the colours of the wires in the mains lead may not correspond with the coloured marking  
identifying the terminals in your plug proceed as follows;  
The wire which is coloured 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 coloured GREEN or GREEN  
and YELLOW.  
The wire which is coloured BLUE must be connected to the terminal in the plug which is  
marked by the letter N or coloured BLACK.  
The wire which is coloured BROWN must be connected to the terminal in the plug which is  
marked by the letter L or coloured RED.  
DO NOT CONNECT/SWITCH ON THE MAINS SUPPLY UNTIL ALL OTHER  
CONNECTIONS HAVE BEEN MADE.  
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CONNECTING YOUR AMPLIFIER  
Setting up your amplifiers is rather easy.  
1. Connect all source components (turntable, CD, Tuner, Tape DAT, etc.) to  
your preamplifier.  
2. Connect the interconnects from the output of the preamplifier or switching  
center to the RCA input on the top rear of the amplifiers. IF your source has  
a truly BALANCED output, connect TO the XLR input and select the  
balanced input. This switch is a locking type to prevent inadvertant or acci-  
dental switching (say, while cleaning). To engage this switch, PULL OUT  
the toggle then gently switch the toggle. Do not force the switch to engage or  
you may break it. If using a standard UNBALANCED source, select and use  
the unbalanced RCA connector. This amplifier will not function properly if  
you are using the wrong input for your application. The XLR input is wired  
PIN1 GROUND, PIN 2 POSITIVE, PIN 3 NEGATIVE PHASE.  
3. Connect the hot or "+" speaker cable to the red binding post and the common  
or "-" speaker cable to the black binding post (See diagarm 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 break the connections inside the amplifier.  
4. Ensure that the "mains" switch on the front panel is in the "off" or "0" posi-  
tion and the OPERATE / STANDBY switch is in the STANDBY mode.  
5. Turn on Preamplifier and any source components you plan to use.  
6. Plug amplifier into wall outlet.  
7. Switch the square mains power switch to the ON position and allow the  
amplifier a minute or so to 'warm up'. The blinking LED will indicate that  
the amplifier is in STANDBY mode.  
8. Engage the soft-start swich to the OPERATE position. The blinking standby  
LED will extinguish.  
9. Turn up the volume and enjoy.  
10. After your listening session, if you wish to leave the amplifier in the energy-  
saving and 'EVER-WARM' STANDBY mode, engage the OPERATE/  
STANDBY switch to the STANDBY position. The standby blinking LED  
will remind you that the amplifier is in STANDBY mode.  
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B+ MAINS  
FUSES  
IEC MAINS  
IN  
INPUT  
RCA  
OUTPUT  
10  
8
3
6
1
5
6414  
6414  
9
7
4
2
12AT7  
Amplifier Overhead View  
Tube Location  
OUTPUT TUBES:10 x RUSSIAN EL34G  
The EL34 type we recommend are the Russian up-rated EL34G. This has been proven to be the most rugged and  
reliable of this type and we strongly emphasize that only the RUSSIAN EL34G's should be used in this amplifier. The  
MANLEY 250/100 WATT MONOBLOCK has been thoroughly optimised around this tube. Use of unapproved tube types can  
and will void your warranty. We have selected the tubes for equality of current draw in our custom-built computerized tube  
tester for each of your monoblocks . Although each tube bias can be individually adjusted, "batched" tubes as we have selected  
are thouroughly beneficial to the amplifier's performance.  
DRIVER TUBES: 1 x 6414  
The 6414 is an American military uprated version of the 12BH7A with increased current drive.  
INPUT TUBE: 12AT7WA  
The 12AT7WA has several equivalent numbers, (12AT7, 12AT7A, 6201, ECC81, etc.) Any of these types may be  
used. We have selected this 12AT7WA very carefully for noise, microphonics, and constancy.  
Replacement tubes of premium quality are always available from MANLEY LABORATORIES.  
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XLR  
BALANCED  
INPUT  
RCA  
INPUT  
SPEAKER  
OUTPUT  
BINDING  
POSTS  
B+ FUSE  
SLO-BLO  
MAINS IN  
IEC  
MAINS  
FUSE  
SLO-BLO  
BALANCED  
UNBALANCED  
SWITCH  
REAR VIEW OF AMPLIFIER  
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FRONT VIEW OF AMPLIFIER  
OPERATE  
STANDBY  
TRIODE  
TETRODE  
OPERATE  
STANDBY  
EVER-WARM  
SOFT START  
SWITCH  
MAINS  
POWER  
ON / OFF  
SWITCH  
1 2 3 4  
5
6
7
8
GROUND  
FRONT VIEW OF AMPLIFIER  
WITH INSERT REMOVED  
POWER  
LED  
SHOWING BIAS MEASUREMENT POINTS  
AND BIAS ADJUST POINTS  
STANDBY  
LED  
(BLINKING)  
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BIAS PROCEDURES  
The Manley 250/100 Monoblock Amplifiers uses a fixed bias system that requires very little  
attention. If you wish to adjust or check the bias, follow the following steps.  
For this procedure you will need a voltmeter (a hand held autoranging DMM digital  
multimeter is the easiest), a 3/32" allen key, and a small 1/8" flat screwdriver.  
1.  
Remove the four silver hex cap head screws which secure the insert to the faceplate.  
Also then remove by hand, the two knurled black decorative nuts on the Triode and Soft-  
Start switches. On page 8, which shows the FRONT panel of the amplifier, you can see 8 red  
tip jacks plus the ground point. To measure the current draw of each output tube place the  
POSITIVE meter probe into the first red tip jack. (If you read a negative reading reverse the  
meter probes, no harm will be done.)  
Set the meter to read 'millivolts' DC (direct current).  
2.  
Each of the ten output tubes can have its own bias adjusted by adjusting its own bias  
adjust pot. Above the measurement tip jacks you can see each tube's bias adjust pot.  
3.  
The first step to setting the bias is to turn on the amplifier and ensure that there is  
zero signal input, either leave the preamplifier or source signal turned off or unplug the  
amplifier input. Also, leave your loudspeakers connected as these provide an ideal load on  
the output. (DO NOT EVER OPERATE YOUR AMPLIFIER WITHOUT SPEAKERS  
CONNECTED!) It is recommended that you leave the amplifier on long enough to ensure  
that the tubes have reached their stable current draw, at least 1/2 hour is recommended.  
5.  
Place the meter probes in the first red tip jack . Adjust the first bias trim pot slowly  
until you measure 275mV to 300 mVDC (0.275V to 0.300VDC). Since you are measuring  
across a 10 ohm cathode resistor, this would correspond to a 27 to 30 mA current draw for  
each tube by Ohm's law. A reading of 0mV can indicate a failed tube, or an open cathode  
resistor. A reading of 0mV on ALL tubes (powered on condition) can mean the B+ fuse has  
blown. The cause of this should be investigated before simply putting a new fuse in.  
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 remaining tubes, switching to the next tube point and  
adjusting the next trim pot each time. After you have adjusted all the output tubes, recheck  
and repeat the procedure as they will drift a little bit during adjustment. Once they are all set,  
your amplifier should be in perfect operation.  
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OPERATIONAL NOTES  
SWITCHING ON -- SOFT START  
The MANLEY 250/100 is equipped with a SOFT-START circuit which lessens the initial stress the  
amplifier takes upon turn-on. We recommend that you use this soft start facility whenever you turn  
the amplifier on and especially when cold.  
1. Ensure that the "mains" switch on the front panel is in the "off" or "0" position  
and the OPERATE / STANDBY switch is in the STANDBY mode.  
2. Turn on preamplifiers and all source components you plan to use and let them warm up  
for a minute.  
3. Switch the square mains power switch to the ON position and allow the amplifier a  
minute or so to 'warm up'. The blinking LED will indicate that the amplifier is in  
STANDBY mode.  
4. Engage the soft-start swich to the OPERATE position. The blinking standby LED will  
extinguish.  
5. Turn up the volume and enjoy.  
THE EVER-WARM MODE  
After your listening session, if you wish to leave the amplifier in the energy-saving and 'EVER-  
WARM' STANDBY mode, engage the OPERATE/STANDBY switch to the STANDBY position.  
The standby blinking LED will remind you that the amplifier is in STANDBY mode. The amplifier  
will draw only 400mA (30 watts @120VAC) from the mains outlet-- certainly an energy saving  
way to keep your amplifiers always ready to listen to!  
TRIODE / TETRODE OPERATION:  
With the TRIODE / TETRODE switch, the amplifier may be set for TRIODE or  
TETRODE operation. When the switch is in the lower position, the amplifier is in TETRODE  
mode which will produce well over 250 watts. When the switch is in the upper position, the  
amplifier is in TRIODE mode which will produce half the power of TETRODE operation but as  
fans of triodes know, nothing can match that sweet seductive sound of triodes! For some more  
demanding energetic music, large rooms, or for power hungry inefficient loadspeakers, you might  
find you will need the extra power of tetrode operation. Other times and other situations will find  
you very well satisfied with the triode mode. One major rule applies for switching between triode  
and tetrode:  
THE AMPLIFIER MUST BE TURNED OFF BEFORE SWITCHING BETWEEN  
TRIODE AND TETRODE!!!!  
Follow turn on SOFT START procedure above when re-powering up the unit.  
TUBE LIFE  
You should expect extended life from the tubes in your MANLEY 250/100 if you adhere to the  
procedures described above and check your bias at least once every 2-3 months. We stock all the  
tubes in these amplifiers should you ever need replacements (and at very reasonable prices too!)  
FUSES  
The fuses used in your amplifier are standard 1/4" x 1 1/4" SLO-BLO types. The correctly rated  
fuse has been installed at the factory for your country's voltage. If replacing a fuse, always unplug  
the amplifier's power cord from the wall outlet and always use the exact same type and ampere  
rating fuse as the one you are replacing. Failure to do so will void your warranty and can be a  
dangerous fire hazard. NEVER replace a fuse with thick wire, tin foil, gum wrappers, or anything  
else other than the correct fuse!  
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SPECIFICATIONS  
Vacuum Tubes:  
Output Power  
10 x EL34G (Output), 2 x 6414 (Driver),  
1 x 12AT7 (Input)  
TETRODE: 240 Watts (@1.5% THD 5 ohm load)  
TRIODE: 100 Watts (@1.5% THD 5 ohm load)  
Frequency Response, +/- .5 dB  
Input Sensitivity  
10 Hz - 80 KHz  
1 V  
Input Impedance  
100 KOhm  
5 Ohm (fixed)  
-80 dB  
Load Impedance  
S/N Ratio @440W  
Power Consumption  
30 Watts  
Quiescent (STANDBY MODE)  
815 Watts  
Full Power (@1.5% THD 5W load)  
Mains Fuse  
100, 110, 120V  
220, 240 V  
8 A (Slo-Blo)  
4 A (Slo-Blo)  
B+ Fuse  
1 A (250V)SLO-BLO  
W=19, D=13, H=11 inches  
63 lbs EACH  
Dimensions  
Shipping Weight  
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WARRANTY  
All Manley Laboratories equipment is covered by a limited warranty against defects in materials  
andworkmanshipforaperiodof90daysfromdateofpurchasetotheoriginalpurchaseronly.A  
furtheroptionallimited5yearwarrantyisavailabletotheoriginalpurchaseruponproper  
registrationofownershipwithin30daysofdateoffirstpurchase.  
Properregistrationismadebyfillingoutandreturningtothefactorythewarrantycardattachedto  
this general warranty statement, along with a copy of the original sales receipt as proof of the  
originaldateofpurchase. Only1cardisissuedwitheachunit, andtheserialnumberisalready  
recordedonit.  
Ifthewarrantyregistrationcardhasalreadybeenremovedthenthisisnotanewunit, andis  
therefore not warranted by the factory. If you believe this to be a new unit then please contact the  
factorywiththedetailsofpurchase.  
Thiswarrantyisprovidedbythedealerwheretheunitwaspurchased,andbyManleyLaboratories,  
Inc. Underthetermsofthewarrantydefectivepartswillberepairedorreplacedwithoutcharge,  
exceptingthecostoftubes.Nowarrantyisofferedontubes,unless:  
1.aManleyLaboratoriespreamplifierisusedwithaManleyLaboratories amplifier,and  
2. thewarrantyregistrationcardisfilledout.  
In such a case a 6 month warranty on tubes is available with the correct recording of the serial  
numberofthepreamplifieronyourwarrantyregistrationcard.  
IfaManleyLaboratories productfailstomeettheabovewarranty,thenthepurchaser'ssole  
remedyshallbetoreturntheproducttoManleyLaboratories, wherethedefectwillberepaired  
withoutchargeforpartsandlabour.Theproductwillthenbereturnedviaprepaid,insuredfreight,  
methodandcarriertobedeterminedsolelybyManleyLaboratories.Allreturnstothefactorymust  
beintheoriginalpacking,(newpackingwillbesuppliedfornochargeifneeded),accompaniedby  
awrittendescriptionofthedefect,andmustbeshippedtoManleyLaboratoriesviainsuredfreight  
atthecustomer'sownexpense.Chargesforunauthorizedserviceandtransportationcostsarenot  
reimbursableunderthiswarranty,andallwarrantees,expressorimplied,becomenullandvoid  
wheretheproducthasbeendamagedbymisuse,accident,neglect,modification,tamperingor  
unauthorizedalterationbyanyoneotherthanManleyLaboratories.  
Thewarrantorassumesnoliabilityforpropertydamageoranyotherincidentalorconsequental  
damagewhatsoeverwhichmayresultfromfailureofthisproduct.Anyandallwarranteesof  
merchantabilityandfitnessimpliedbylawarelimitedtothedurationoftheexpressedwarranty.  
AllwarranteesapplyonlytoManleyLaboratoriesproductspurchasedandusedintheUSA.  
Somestatesdonotallowlimitationsonhowlonganimpliedwarrantylasts, sotheabove  
limitations may not apply to you. Some states do not allow the exclusion or limitation of incidental  
orconsequentialdamges,sotheaboveexclusionmaynotapplytoyou.  
Thiswarrantygivesyouspecificlegalrightsandyoumayalsohaveotherrightswhichvaryfrom  
state to state.  
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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  
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: MANLEY REFERENCE 250/100 MONOBLOCK  
SERIAL No. ______________________________  
PURCHASE DATE ______________ SUPPLIER _______________________  
NAME OF OWNER _______________________________________________  
ADDRESS ______________________________________________________  
CITY, STATE, ZIP________________________________________________  
TELEPHONE NUMBER ___________________________________________  
Comments???? ___________________________________________________  
________________________________________________________________  
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