User guide

10
TECHNICAL DETAILS
CHANNELS: The Combi (XLR / 1/4") jack is wired to provide a 2400 ohm load for XLR sources like mics,
and 82K ohms for 1/4" plugs either balanced or unbalanced. On MIC VERSIONS Phantom power can be
injected with the back panel switches and uses a pair of traditional 6K8 resistors. Also on MIC VERSIONS,
the signal is optionally phase reversed with a relay. On all versions, the next stage is a very low noise
instrumentation amp / DC servo. For those into numbers, noise is rated at 1nV/÷Hz, THD+N at .0009%, and
it cleanly accepts +30 dBu signals. Similar circuits have been used on the most expensive consoles, dedicated
mic pres and high end A to D converters, but not this many channels at this price. On MIC VERSIONS, this
signal is sent to a line driver, the INSERT jack and back into an impedance converter, the "insert relay" and
then to the MIX GAIN pot. With INSERT bypassed or on the line versions the mic pre feeds the MIX GAIN
pot directly. The output of the pot is buffered with 10 dB of gain plus a bipolar class AB line driver and fed to
several points. These include the MUTE relay, Aux pot, Pan pot and Channel Output Line Driver. The latter
is isolated with a balanced line driver. The Aux pot and Pan pots are 1K conductive plastic Bournes pots for
reliability and low noise. There is a .1" header and jumper that allows the Aux pot to be pre-fade, post-fade
and post-fade&cut. The final step is 2K2 build-out resistors for the summing busses. All signals use at least 2
pins on the header for signal integrity, redundancy and low impedance.
Removal of a module of 4 channels is accomplished by:
1) Unscrewing and sliding back the top perforated cover.
2) Pulling up and off the 4 IDC ribbon connectors from the headers.
3) Removing the 8 plastic nuts from the 1/4" jacks and the 8 black 4-40 screws from the combi jacks
4) Removing the 4 hex head 4-40 screws that hold the black engraved front panel.
5) Pull the module forward, and to the right to clear the XLR locks.
A single channel can be removed from the module by:
1) Disconnecting the wire or ribbon between the channel and the switch board.
2) Disconnecting the Buss Wire (48V) connecting the 4 channels.
3) Removing the 3 knobs, and nuts under that mount the pots and/or switch.
Each channel uses a pair of 30 ohm 1/2 watt resistors on the +/- 24 volt supplies for fusing and isolation. They
are next to the 2200uF filter caps, and are intended to smoke and fry if a serious short exists in the channel
and prevent much bigger problems.
Replacing the meter lamps in the Manley 16x2 Mixer:
Assure the power is OFF and the unit is UNPLUGGED FROM THE WALL before beginning.
Note: Starting middle 2003 we are using LED lights replacing the lights bulbs, we can
provide the parts to switch to led's for older units.
1) Using a 3/32” allen key, unscrew the three stainless-steel cap head screws that hold the meter/monitor
section’s black engraved panel insert .
2) Using a 1/16
th
allen key, loosen the two set screws that secure each knob. Remove the 4 knobs. Using a 1/
2” nut driver or crescent wrench, remove the 4 panel nuts that hold these three pots and the rotary switch.
3) Now you can pull the black engraved insert panel away from the tube boards .
4) On earlier models, using a #1 phillips screwdriver, remove the two phillips screws that hold each meter
lamp socket at the rear of the white plastic light box housing and replace the bad lamp.
5) On later models:
a. Unscrew the tip of the locking power switch toggle. Using a 5/16” nut driver or adjustable crescent
wrench, remove the power switch securing nut.
b. Using a 3/16” nut driver or small pair of needle nose pliers, remove the 4 brass nuts that hold the meters to
the meter printed circuit board.
c. Now you can pull off the printed circuit board away from the rear of the meters and replace the bad lamp.
This 12V lamp is provided to us from Sifam with the meters. It is not a commonly available part.
Please contact the Manley service department to order meter lamps.
Reassembly is the reversal of removal..