Empirical Labs EL-9 - Manual (Page 13)

Stereo Operation & 5.1 Surround Use
The user should plug in a short ¼” mono phone cable to both unit’s Link jacks, and match the
controls on the two Mike-E’s for Stereo Buss use. Turn on the LINK setting on both units. Matching
the front panel controls will yield highly accurate response between the two channels. You do not
have to remove the cable to use them as two independent “mono” units. Footnote: If linking two
Mike-E’s, gain reduction will differ if one has an attack of 100mS, and the other doesn’t.
Changing the Fuse
– (Using the extra fuse inside)
Pull out the power plug from the AC outlet, open unit, and ensure fuse closest to rear of the unit is
blown. (Note: The fuse closer to the front panel is a spare fuse and is not connected to anything).
Gently pry out one end of the blown fuse and then the other, replacing it with extra fuse provided
near front right of unit. A small screwdriver may be helpful. Lay the top cover over unit, temporarily
plug in AC, and turn it on to ensure that the fuse doesn't blow again, indicating a possibly more
serious problem (see troubleshooting). If OK, unplug unit, replace spare fuse in front of PCB if
possible, firmly screw down top cover and return the unit to normal use. Any fuse from .5 to .75A
should be safe, but .5A (1/2A) is what is specified and used at factory for both 115 & 230Volts.
Line Voltage Select
For operation in different countries, changing the voltage for 115 or 230V operation involves
unplugging the unit and removing top cover. Inside on the right (as the front of the unit faces you), is
a switch with 115 or 230V showing on its face. Select the desired voltage by sliding the switch until it
indicates that voltage and you’re done. Replace cover and screws.
Troubleshooting
‰ Unit is on but nothing is coming out. If using a condensor Mic, check that the 48Volt Phantom
supply is on. (See the mic documentation). BE CAREFUL BECAUSE SOME MICS SUCH AS
RIBBON MICS, CAN BE DESTROYED WITH PHANTOM POWER! Bypass the CompSat and see
if a signal appears. If it does, make sure the DRIVE is not on 0 which turns off any signal going into
the CompSat Is an jack plugged into the INST IN and not being used.
‰ Clip light comes on but you shouldn’t be near clipping. Check that the DRIVE control isn’t
turned up too far when CompSat isn’t being used. Many potential “clip” points are monitored in the
unit and even an unused section (like CompSat) that clips will light the CLIP indicator.
‰ Distorted output - If there is any un-musical distortion, chances are you're hard clipping. Try
turning down the input gain. The BAD! Clip LED should light just before any internal clipping. If
clipping persists, try lowering the DRIVE control, if the CompSat is being used. Check that only
one input on the rear can is being used, since the inputs are connected together in parallel. Check
that the output cable is properly wired and any unused output pins (2 or 3) on the active XLR are
floating (left unconnected). Shorting an active output pin will not harm the unit but can show up as
distortion. The transformer output should always have pins 2 & 3 going somewhere.
‰ Low or thin sounding output - If using the transformer output, try switching it to the active
output and see if the level and low frequencies improve. If they do, the transformer output wiring is
incorrect. Follow the explicit instructions on the rear panel, or see page 10 in this manual.
‰ Compressor doesn’t work -The section is bypassed, in 1:1, or there is a sidechain or link
problem. Unplug the sidechain and link cables and see if problem is corrected. Otherwise, the
unit is possibly out of adjustment Please return the Mike-E to factory for re-calibration.
‰ Unit seems noisy - If you are compressing a noisy signal, the noise could be accentuated. See
if turning down the DRIVE control turns the noise down. By keeping the Mic Input gain higher
without clipping, one can marginally improve signal to noise, even with CompSat used.
‰ Phantom Power doesn’t work – Make sure you only have ONE input going to the device. If you
have two inputs, one can short out the other, or short the 48V phantom power.
‰ No sign of life - Check power cord for firm connection. If still no life unplug unit and open top
cover by removing all top screws and check fuse toward rear next to transformer. If it is blown,
replace it with extra fuse (see changing the fuse, above). If fuse is OK, ensure Voltage select
switch is set to current wall outlet voltage (115, 230 VAC). If unit keeps blowing fuses, and there
is nothing visible floating around inside, it is best to return it to the factory for servicing.
‰ Channel levels seem mismatched between two Mike-E’s – Pots never perfectly match. On
Audio Taper pots, the most inaccurate spot is when the knob is on 5 –6… the most used area! If
the units Drive or Output pots seem to differ slightly in that area, the best thing to do is write down
your settings on a copy of the recall sheet in this manual. The factory tries to make all units match
within 2.5 small tics on the knobs, but closer match is nearly impossible. Contact factory if match
is more than 2.5 tics off between two units. 13
What is the Mike-E?
The Mike-E is a modern digitally controlled Microphone Preamplifier with many unusual features to
soften and warm the source, along with an excellent compressor/limiter. Mike-E offers an incredible
performance transformer coupled mic preamp, whose noise floor exceeds any microphones noise
floor by many decibels. The Comp/Sat section is a compressor along with a soft clipping circuit, that
offers stepped and recallable ratio, attack, and decay controls
Mike-E's Seven Circuits:
1) Mic Preamplifier with super low noise and detented gain switching.
2) A built in “Direct Box”, called the “Inst In”, which offers unparalleled
distortion, noise, and frequency response when preamping instruments.
3) A “Colored” 80Hz High pass filter that emulates the warm low frequency
cut of our favorite vintage equalizers.
4) A Phase Switch to invert the audio signal 180 degrees.
5) CompSat section that offers both a musical Compressor/Limiter, and a
unique tape-like saturation circuit.
6) Emphasis Circuit. A high frequency emphasis system to soften high
frequency “pile-ups” and further the creamy color of the Mike-E.
7) Mix Control to allow the blending of the Compressed/Saturated signal,
with the clean un-processed “Dry” signal.
Using the Mike-E for the first time
Hookup is straightforward. Either the XLRs or phone jacks can be used. Only the front INST
Jack is high impedance. TURN OFF PHANTOM POWER BEFORE PLUGGING ANYTHING INTO
THE REAR INPUTS! In relation to the phone jack tips, pin 2 is wired "hot" on the XLRs. But if you're
using the XLRs in and out, it doesn't matter which pin is hot, as long as you're cabling is in phase.
The Input Impedance at 1kHz is 600 Ohms on the Transformer input. This is compatible with
microphones and most modern line level low impedance output devices. (See SECTION DETAILS)
Connecting both the + and - input pins is preferred. The standard output is a balanced active
stage, driven by two amplifiers. If you use the Active XLR output in an unbalanced system,
leave unused pin floating (pin 3 usually) If you have one of the transformer output options, both
pins 2 & 3 should be connected for proper termination. See wiring section for greater details (p10 ).
You can only have one input in use at a time on the Mike-E.
The Mike-E controls are generally organized on the front panel in the same order as the
electronic circuits inside, IE the Input is the first circuit, Highpass and Phase circuits next, etc. See
the block diagram (p11) for more detail.
Setting Mic Gain – The CLIP TEST
. THE PREAMP GAIN IS THE MOST CRUCIAL
CONTROL TO SET PROPERLY ON THE MIKE-E! Set initial levels by using the following CLIP-
TEST. Turn CompSat Drive to 0 and Output to 5 so those sections don’t clip. Have the source
produce a loud “peak” sound repeatedly, and adjust input mic gain till BAD! LED just lights. Then
adjust mic gain down one (sometimes two) 5dB step(s) from this CLIP TEST to allow headroom. The
Mike-E has a huge “sweet” spot. Most mics operate well at 30 to 40dB of gain for voice level
sources. If not using the CompSat, you can set output level to 7 or 8 for initial level.
Using the CompSat circuit is a world unto itself, offering some unique processing for the
otherwise pristine Mic Preamplifier. Enable the CompSat by pressing the Ratio taking it “out” of
Bypass to 1:1 or an actual compression ratio. With so many options, lets make it simple by using the
CompSat as a soft knee compressor only. Set the MIX control to full CW COMPRESS (10 on MIX
knob), and set the compressor to 4:1 attack 8mS, release .1S. Use the DRIVE control to adjust how
much compression you want. Until you are really experienced, its best to be conservative at first
when tracking, keeping the Gain Reduction below 13dB. Because of gain reduction, you may have
to make up the gain on the output control. There is tons of headroom once the compressor is
engaged, and running the output knob higher, or even all the way to 10 is perfectly fine, as long as
no Clip indicator (BAD!) lights. If the CompSat is bypassed, it’s best to keep Drive at 0.
Using the Instrument Input – SIMPLE! Just plug in your instrument (bass, guitar, synth etc)
into the “Inst In” on the front panel, adjust gain, and VOILA… a high performance Direct Box!
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