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TECH  NOTES

8

SWITCHING ON
The power switch is located on the right hand corner of the front panel. When one first turns on the power the LED
next to the switch is red, indicating "mute"- after about twenty seconds it turns green and audio can pass. This
prevents thumps or pops during warm-up and shut-down. The circuit is smart enough to ignore short black-outs. The
audio does not normally pass through the relay involved - the relay, when muted, simply shorts the output. Do not
switch on and off rapidly in succession as this is not good for the power supply. A recent update added high voltage
shunt regulators so that AC power variations were not reflected to the output. We also added output transformers.

TUBE LIFE
As with all tubes, their quality degrades with age.  This is due to cathode emission, a natural process found in all
tubes.  Excessive increase in noise (hiss) can indicate the need to replace a tube. Usually, the 5814/12AU7A will be
the one to try first as this is the tube in the gain stage. The 6414 is the output tube. Microphonics are a natural
occurrence found to some extent in all tubes. We try our best to select the least microphonic tubes possible.

TUBE SUBSTITUTION
This circuit has been optimised around the 5814 and the military 6414 tube types. We also believe these are the best
tubes for your unit. Replacement tubes can be obtained from Manley Laboratories. However, if you're stuck in a
pinch, the following tubes are approved substitutes for this unit:
For the 5814:  12AU7WA, ECC82  (exact substitutes)
For the 6414: 12AT7, ECC81, 12BH7A (not exact substitutes, but they will work fine with a little less current output)

CUSTOM VERSIONS
For mastering use, we also build a custom version of the Manley MID Frequency Pultec EQ which has
1/2dB switching BOOST and CUT controls replacing the continuously variable controls found in your unit. We also
build a Mastering Version of our Pultec EQP1-A.

SERVICING and TUBE REPLACEMENT
High voltages are present in this unit when powered and for 10 minutes after power is removed due to the slow
discharge of the high voltage capacitors. Before opening the top, remove the mains cable and let the unit "sit" for
about 10 minutes. Even then it is good practice to only use one hand in any high voltage gear and/or use rubber
gloves. Do not touch the circuit board or and resistors and capacitors as there may be some charge still remaining.
Wiggling the tubes slightly back and forth helps when removing or inserting them. Given these precautions, replacing
tubes is as easy as changing a light bulb. There is a metal tube shield over the 5814, Twist it slightly counter-
clockwise to remove it. It is used to reduce hum and light pick-up. Replace it after changing the tube.

6414

output tube

5814

input tube

EQ SECTION

POWER

TRANSFORMER

MIT Multicap

output capacitor

Gain make-up

amplifier

Summary of Contents for Enhanced Pultec Mid Frequency Equalizer

Page 1: ...MANLEY LABORATORIES INC OWNER S MANUAL ENHANCED MID FREQUENCY PULTEC EQUALIZER...

Page 2: ...ON 3 EQ HINTS 4 FRONT PANEL 5 REAR PANEL 6 MAINS CONNECTIONS 7 TECH NOTES 8 TROUBLESHOOTING 9 10 CURVES 11 WARRANTY 13 WARRANTY REGISTRATION 14 APPENDIX WIRING YOUR OWN CABLES TEMPLATE FOR STORING SET...

Page 3: ...he distortion as such The older transformers suffered from wide band distortion and losses inthehighs Thisisrarelywanted Modernhighqualitytransformersaremuchbetterinthehighsandgenerally much lower dis...

Page 4: ...lexible for mastering Many of the most recognised engineers suggest cutting rather than boosting According to them it sounds like less phase shift and resonance They would start by dipping a little in...

Page 5: ...ful hard sounds while the 5 or 7 kHz are often used to compensate for microphone diaphragm resonances E MID FREQUENCY DIP peak Provides continuously variable CUT from 0 to 10 or 12 dB to the selected...

Page 6: ...inserted Tip Signal Sleeve Ground Ring unused Use either output but not both F GAIN SET PRESET This control adjusts the feedback over the line amplifier It is preset for unity gain however additional...

Page 7: ...ire which is coloured BROWN must be connected to the terminal in the plug which is marked by the letter L or coloured RED This unit like most pro gear is designed for third pin AC mains ground See the...

Page 8: ...it Replacement tubes can be obtained from Manley Laboratories However if you re stuck in a pinch the following tubes are approved substitutes for this unit For the 5814 12AU7WA ECC82 exact substitutes...

Page 9: ...BYPASS The signal goes through the tube stage in Bypass Let s assume the wiring has been checked twice There is about a 98 chance it is a tube If it were solid state you would generally send it back...

Page 10: ...we know of David showed us that they have less coloration than Penny Giles faders on bigconsoles Unfortunatelythey feel loose Wecouldusecheapunsealedpotslikemostothercompaniesbutthenwewould not feel...

Page 11: ......

Page 12: ...015 Noise Floor Gain set to minimum 80 dB Wideband Signal to Noise 126 dB typical Maximum Gain via trim on back 5 dB to 5 dB Maximum EQ Boost 12 dB low mids 10 dB high mids Maximum EQ Cut 12 dB 10 db...

Page 13: ...rwarrantyregistrationcard IfaManleyLaboratories productfailstomeettheabovewarranty thenthepurchaser ssole remedyshallbetoreturntheproducttoManleyLaboratories wherethedefectwillberepaired withoutcharge...

Page 14: ..._ SUPPLIER ______________________ PLEASE DETACH THIS PORTION AND SEND IT TO MANLEY LABORATORIES MODEL MANLEY MID FREQUENCY PULTEC EQ SERIAL No ____________ PURCHASE DATE ______________ SUPPLIER ______...

Page 15: ......

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