Manley Langevin HP-100 More-Me Headphone Mixer 2/1995 - 6/ 1996 D-SUB - Manual (Page 2)

Individual external power supplies. These external supplies are not "wall warts". External power
supplies create less problems, such as hum, in the stations. They reduce the weight and size of the stations
making it easier to accomidate mic stand mounting. By having individual power supplies a studio does not
have to rewire to have stations in iso-booths. It also increases system reliability because when a central
power supply is a problem it is a central problem. Central power supply schemes also use the audio cabling
and connectors which is not a recommended practice for valid electrical reasons.
Both 1/4" jacks and multi-connectors offer versatile wiring options. Balanced audio inputs and
control logic combined with the recommended wiring schemes prevent the possibility of ground loops and
hum. These inputs are fine with either balanced or unbalanced signals and +4 or -10 signals. Low noise
circuits are used with plenty of gain range.
4 headphone jacks. While the unit was primarily designed with having a separate headphone
mixer for each musician there are many situations where several musicians can share one station, such as
harmony vocals. We could not fit a separate volume control for each headphone jack in the unit nor do we
like the loss of damping factor and reliability that these attenuators cost. An external box with 100 ohm to
500 ohm 5 watt pots are cheap to buy or easy to build if needed.
Overload indicator (O/L) flashes 3 to 6 db below clipping and typically 10 db below audible
distortion. However in practice when it is flashing the volume should be reduced.
The stations provide 3 audio outputs at all times. Two are used for a check of the headphone amps
outputs so that the control room can hear exactly what the musician has mixed or messed up. The third line
is the built in mic output and is not affected by the talk switch.
Simple, intuitive operation. No training or expanations to the talent is usually necessary.
Just label the faders. Not all headphone systems are this easy to use. Very few musicians want to be trained
to use your studio.
As LANGEVIN is the solid state branch of MANLEY LABS one can expect the unusual degree
of high quality parts and construction. There are very few manufacturers of pro audio gear using this level
of high quality parts. All Op Amps are Burr-Brown OPA2604 FET type running with 21 volt regulated
supplies and were purpose designed for high quality, clean audio. The faders and right hand pots are
ALPS and the pan pots are conductive plastic Bournes. Signals pass thru only one capacitor per phase and
these are polypropeline. Resistors are all 1% metal film and most are 1/2 watt. The Power Amps are
monolithics, are very new and designed to provide 150 watts peak and 60 watts continuous into 4 ohms per
side. Because headphones usually require volts rather than watts, we limit the supply current appropriately.
These amps are designed to never produce any click or thump or DC during power-up or power-down and
thus will damage fewer headphones. They are fully protected against shorts, over heating and power supply
faults. Best of all they sound very good (for solid state) and will drive headphones loud enough for
drummers. These amps will drive speakers to reasonable volumes if needed, however watch out for over-
heating (they will simply mute) and keep in mind that the stations were not designed for full power sine
wave specs below 40 ohms.
Wiring requirements are only as much as needed. Different types of studios may only need or
want certain functions. Multi-connectors are not needed for a basic system. The following sections give
some of the wiring scenarios from the simplest to the most comprehensive. The simpler set-ups are typical
of how many major studios are presently operating. Most of them are using one or two stereo power amps,
lots of speaker cable and those boxes with a few volume controls. Each part of such a system will work but
always sounds poor. They could work the way they are used to and improve the headphone sound for little
cost if they gave more of a damn about the musicians performance needs than their lounging needs.
INSTALLATION
The most basic system only requires 2 lines from the control room to the studio. It is possible to
use spare mic lines with the appropriate adaptors. Patch the consoles Cue Mix to the mic lines. In the studio
patch from the mic lines to the stereo input channels. Use the console's TB (Talk Back) to talk to the talent.