Empirical Labs EL-Rx - Manual (Page 3)

1) Holding an EQ button for 1 second will make it move backwards to previous frequency.
2) Tape Emulator – There is a unique soft clipper in the DocDerr that can be used heavily by
disabling the compressor. Press the two outside buttons (LF and HF) to toggle the compressor
on and off. Then turn Mix 100% and adjust saturation with input knob.
3) Hi Shelf EQ from Parametric – Tune HF PEQ to Max Freq(15KHz), and use as shelf EQ.
4) Decreasing output Level – A jumper on the right/rear side of the module (as you face the
front) can be moved to the rear position to lower the output level by 6 dB. From the factory the
output is true differential, and the levels usually better suit recording directly into a DAW. If
going to –10dBu devices, move the jumper towards the rear to lower level and prevent clipping.
5) Factory Default - If you want to set all the jumpers back to their factory default, move them all
to the front position.
6) DAW parallel processor – The DocDerr’s Mix control can prevent frustration by being used as
a processor in a workstation, allowing parallel processing without delay alignment issues.
7) EL500 Rack – This single height, 2 space rack works great with the DocDerr module. It has a
preamp built in, so you don’t have to move DocDerr jumpers to use as instrument preamp.
Stereo Operation & 5.1 Surround Use
.
The user needs to enable linking of two units on the power supplied rack, if available. Pin 6 on
the EDAC card connector needs to be connected between the modules that will be linked. Once the
pins are linked (connected), two units will have the compression locked together, and no image
shifting will occur. The user would usually match the other controls, especially the input drive, and
the MIX control. Different EQing between channels can sometimes be useful.
On some power supplied racks, the manufacturer provided a place to jumper “link” pads together
with a soldering iron. Empirical Labs EL500 has a dedicated front panel button that allows the users
to link two units together. The EL500 also has an instrument input on the front that can be setup
with gain so the module itself can be operated in LINE input mode, which is differential.
Troubleshooting
‰ Compressor quits working – You may have inadvertently hit the two outside buttons (LF and
HF switches) simultaneously, which disables the compressor in software. Press both buttons
simultaneously again, to enable compression.
‰ Clip BAD! light comes on but unit shouldn’t be near clipping. Check that the Input Jumper
is correct for the source (Instrument or Line In). If you are coming in at Line level, say from a
workstation or recorder, the input jumper should be towards the front (Line Level) or you will most
likely clip the input stage of the DocDerr. If an EQ section is at full boost or cut, you could be
clipping that section, and must lower the input into the unit. Many potential “clip” points are
monitored in the unit. If your instrument is clipping the input, turn down your instruments volume.
‰ Distorted or Thin output - If there is any un-musical distortion, check your Gain Jumper
position, and for hard clipping. If the bad light is coming on, lower the signal going to the DocDerr.
For hot line levels, set Input Gain Jumper towards front (Line In), since it not only adds lots of gain,
but can unbalance an input from a transformer, ruining the frequency response.
‰ Hum – Unit may be too close to power transformer. Move to slot farther away from supply. Due
to its higher current draw, the DocDerr can tax some power supplies. Pull out an adjacent module
and check again to see if hum goes away with lower current. If it does, contact Empirical Labs.
‰ Unit seems noisy - If you are compressing a lot, or boosting frequencies on a noisy signal, the
noise could be accentuated. Try turning down the input gain and see if noise from the compression
gain goes away. If so, noise is coming from before the unit, and being amplified by the compressor.
‰ Unit forgets where it was when power was shut off – Wait 6 seconds before turning it off after
changing setting. There is a 6 second delay to lengthen the lifetime of the non-volatile RAM to long
after we are gone. If it still loses its memory, contact factory for warranty support.
‰ No sign of life - Check power cord for firm connection to powered rack, and that the card is
firmly seated in connector. If still no life, check the fuse on the rack. 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 not another module being used, it is best to return it to the factory for servicing.
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What is the DocDerr?
It’s all about TONE. The DocDerr is a digitally controlled Preamp, EQ, Compressor and
Saturator module good not only for general use, but can single handedly bring incredible tone to any
source, even electrified acoustic instruments. It offers unprecedented amounts of processing and
musicality in an API 500 compatible module. With a mini-computer inside (Microcontroller), one
controls 4 analog EQ sections, and a new dynamic section capable of chopping brittle edges and
digital transients with its compressor and saturation circuits. The DocDerr module is the first
Empirical Labs compressor available in the API 500 series format, and a super-utilitarian processor .
DocDerr's Six Section Types:
1) Low Noise Preamp section, capable of unity, or 16dB of “instrument” gain.
2) A selectable High pass filter to cut annoying sub frequencies out.
3) Three bands of top performance parametric EQ.
4) A dynamic section that offers renowned Empirical Labs compression at an
unprecedented price, in a 500 series format module. This aggressive
compressor has a large “knee”, and is tuned to minimize nasty distortion.
A live instrumentalist has access to classic compression.
5) A tape emulation type circuit that softens the high frequencies, and soft
clips, allowing more RMS level to fit in the same peak level. It’s louder!
6) A mixer that allows the user to blend the uncompressed EQ’s signal with
the compressed & saturated signal.
Using the DocDerr for the first time
The DocDerr is an incredibly deep and powerful little tone-enhancing module. Lets dive in.
Operating Levels – First, before even installing the DocDerr in a rack, make sure the DocDerr has
the input gain jumper set properly for your use. There are two primary ways to hook up the DocDerr:
1) As an instrument preamp with front-end gain, 2) As a line level device/processor. The INPUT
GAIN Jumper allows you to select one of these modes and is located towards the middle rear of the
board. If you are plugging a guitar or bass directly into it, for instance, it should be set towards the
rear for INST mode. For louder balanced LINE IN level signals, it should be towards the front. See
page 3 for a diagram of the Jumpers. The Factory default is LINE IN. (Not unity gain). In
INSTRUMENT IN, the gain increases to 16dB of front end, high impedance amplification.
Use INST jumper setting for an instrument such as your acoustic guitar with built in pickups.
Install in your rack. If your rack has only XLR, use the supplied adapter cable to go from your guitar
to the XLR input of your rack. The output can go directly to powered speakers or a mixer, etc.
First time users should learn the EQ first. Turn the Compressor MIX knob to 0 (No
compression, just EQ) and adjust the EQ controls till you get the creamy sound you want. Select the
frequencies by pushing the buttons, and set boost and cut with the knobs. Holding a button for 1 sec
will cycle backwards. There are 7 frequency selections for each band. When two LEDs light, you
read the frequency below and between the two LEDs. If you hear thumps or low rumble, engage the
HP circuit by pressing two buttons at once, the LF and the MF switches. You can cycle through the
available high pass frequencies by repeatedly pressing these two buttons. Often the two main
problem areas with acoustic instrument tone are low mids and high mids. Pulling out woofy
frequencies between 250 – 500 can make the instrument sound brighter and fuller. If upper mids pop
out, you can pull 1K – 8K with the midrange or high frequencies. Piezo or ceraminc pickups often
have too much energy in the 4KHz area. The DocDerr compressor can help smooth out gain loss
from EQ dips, making a case for touching up your EQ while compression is engaged.
Now lets setup the compressor. Turn the MIX knob on the right to 10 (100% compressor) and
adjust the INPUT Knob until you feel the sustain and evenness of our compression starts to please
you. We worked very hard on this compressor to make it aggressive, yet not unpleasantly distort, as
fast as it is. A live musician may want to maintain his really hard attacks by turning the mix back
from 10, mixing in the dry uncompressed signal. This will let the really loud passages come thru
over the compressed, sustained level. Live, you may have feedback problems with an acoustic
instrument. This often limits the amount of compression one can put on. One can try to pull out the
feedback frequencies with EQ, but often the player will have to ride his volume down at fade-outs.
For line level situations, such as while mixing or on a synthesizer, one would move the Gain
Jumper to the Line Level position (towards the front). This cuts the gain back by 16dB to 0 gain,
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