Manley Langevin Dual Vocal Combo 1999 - 4/2001 LDVC000 - LDVC178 - Manual (Page 8)

CONNECTING YOUR PREAMPLIFIER
Easy - Connect the mic to the Microphone Input XLR, then connect the Line Output to
your tape machine or console. Read on, there are some things to consider.
On the back panel are female XLR’s labelled MIC INPUT A and MIC INPUT B. The
signal from the MICROPHONES get plugged in here. Here are a few warnings and sug-
gestions. These XLR connectors also “send” PHANTOM POWER to the mics. Some mics
can be damaged by the 48 volts of phantom power. A few PZMs and a few ribbon mics
have been known to “fry” when fed phantom power. The suggestion is to ALWAYS have
PHANTOM switched off when switching mics, cables, patches that involve mics etc. You
ONLY use phantom power for PRO SOLID STATE “FET’ CONDENSOR MICS. Tube
mics, dynamic mics, ribbon mics and battery powered mics should have phantom switched
“off”. This is true for all mic preamps. With this MIC PRE you “PULL THE TOGGLE
to SWITCH PHAN-TOM”. It is a locking toggle to prevent “accidents”. The second great
reason for not using phantom if you don’t have to is that - if you change a connection
(patching) with phantom on, then the pre amp will be fed a quick burst of 48 volts (when
it normally is amplifying about a hundredth of a volt), which can then be monitored - usu-
ally once. After you have replaced your speakers, you have learned a valuable lesson about
turning down the volume of the monitors before changing mics or mic patches. This is a
good idea with phantom on or off. Consider a variation of this - any mic connection just
a little bit bad,will be extra noisy with phantom turned on. This goes for cables, patch-
bays, patch cords etc. Suggestion #2 -Avoid running mic signals through patchbays. Some
patchbays “ground” all the “sleeves” which can add a ground loop into your delicate mic
signal. Suggestion #3 - Set up the Mic Pre in the studio near the mic and use a short mic
cable. Why ? Microphones often have “light duty” line drivers and you can lose an audible
amount of signal in long cables. You can get the best fidelity by having the Mic Pre close
to the mic at the “cost” of having to walk into the studio to adjust a level control. You also
avoid almost all of that phantom power / patching problem because now you are patching a
regular line level signal only.
The MIC INPUT XLR PIN OUT is:
PIN 1 = CIRCUIT GROUND
PIN 2 = HOT or positive going phase
PIN 3 = LOW or negative going phase
The LINE OUTPUT XLR PIN OUT is:
PIN 1 = CIRCUIT GROUND
PIN 2 = HOT or positive going phase
PIN 3 = LOW or negative going phase
This is a simple balanced output. It will feed balanced inputs but not unbalanced
inputs “correctly”. When it is plugged into an unbalanced input, expect a 6 dB loss of
output level. Use the 1/4” unbalanced output to drive unbalanced inputs. The best way to
drive an unbalanced input with the balanced XLR is not to connect to PIN 3 at the out-
put XLR - just use PIN 1 (ground) and PIN 2 (signal). Better to have PIN 3’s signal float
than short which will distort quietly and you may not notice the 6 dB loss.
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