Empirical Labs EL-7x - Manual (Page 8)

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TROUBLESHOOTING
UNIT FORGETS WHERE IT WAS WHEN POWER WAS SHUT OFF – Older units used a Non-Volatile memory cap that
could fail after years of use, or possibly have some other type of logic failure. Contact the factory for suggestions or
servicing. Newer units have a delay of 6 seconds before storing last control change. Wait 6 secs and turn off to test.
NO SIGN OF LIFE – Press any button to test. When no processing is engaged, the unit has no LEDs lit on the front panel.
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, pry it out and replace it with extra fuse provided in fuse holder
toward front of chassis. Also, make sure your Voltage select switch is set to current wall outlet voltage (115, 230 VAC).
UNIT KEEPS BLOWING FUSES - Check internal voltage select switch for proper settings (115/230). Otherwise, suspect
a short or power supply problem. Inspect internal components for burned or bulging parts. Try to make sure there is
nothing trapped under the PC board, shorting to the metal case. Attentive visual inspection is still the most effective
troubleshooting tool available.
UNIT RUNS HOT – Leave a space above or below it, or mount in cooler rack. New FATSOs run cooler.
UNIT IS ON BUT NOT DOING ANYTHING - The unit may be bypassed or operating subtly. If bypassed, you need to press
the “BY-PASS” button so red LED goes off. The input and output levels should always affect it unless bypassed.
SLIGHT GAIN DIFFERENCE BETWEEN THE CHANNELS. Pots are like snowflakes: No two are exactly alike. We select
pots and then improve channel to channel match by offsetting the knobs on the pot shafts.
UNIT SEEMS NOISY - Since the FATSO is capable of lots of compression without sounding unnatural, you can often bring
hiss levels up undesirably. If you have 20 dB of gain reduction on a room mic that has a 90 dB S/N, the noise floor will be
raised 20 dB in quiet areas, bringing the noise floor up to 70 dB. Remember your current input level, and then test that
the noise is coming from outside the unit by turning the input knob off (to 0). Try gating before compressing.
KNOBS DON’T TURN TO EXACTLY 0 – When turned all the way down, the pointer is often a little above or below 0. We
do this on purpose as a “calibration”, so knob settings match better than their 10% rating. There are lots of knob tics on
the knobs for recall, even if you need slight adjustment. See above.
SIGNAL DISAPPEARS IN BYPASS – XLR pins 2 & 3 are probably switched in cabling or patch bay.
BARGRAPH SHOWS GAIN REDUCTION BUT VERY LITTLE OR NONE IS ACTUALLY OCCURRING - We use very stable
trim pots and high quality components, but it is possible that long term component aging or failure may require factory
re-calibration. Also, dampness or spills into the FATSO can cause this phenomenon. At present you will have to return the
FATSO to factory, or certified repair center.
BARGRAPH LEDS FLICKER FOR A MINUTE OR TWO AT TURN ON. Unit simply needs to warm up.
DISTORTED OUTPUT - If there is severe, un-musical distortion, chances are you’re hard clipping. Check that the output
cable is properly wired and any unused output pins (2 or 3) on XLR output are floating (left unconnected). Shorting an
output pin will not harm the unit but can show up as distortion in the output driver. The distortion this unit is meant to
impart is harmonic and not crackly distortion caused by hard clipping. If the pinned LED stays on, you must lower the
input. Compression can distort also.
NO OUTPUT - Make sure audio is getting to the unit, and the input and output levels are turned up.
UNIT POPS OR UNNATURALLY PUMPS WITH LOW FREQUENCIES Try a different compressor TYPE.
CHANGING THE FUSE
Caution: Always unplug unit before removing Top cover! Unplug unit, remove top cover, 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 fuse and then the other, replacing it with extra fuse provided near battery holder in front of unit.
A small screwdriver may be helpful. Before putting cover on, plug in unit, keeping hands out of the box, ensure that the
fuse doesn’t blow again, indicating a possibly more serious problem (see troubleshooting). If OK, unplug unit, screw
down top cover and return the unit to normal use. We use a .3A slo blo, but a .5A regular fuse should be fine, Replace
spare fuse in front if available. We went to the expense to keep an extra fuse inside... you should too.
LINE VOLTAGE SELECT
Changing the voltage for 230 or 115 operation is easy, but 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.
BASIC WIRING
Wiring is straightforward. Connect AC line cord to 3 prong jack, plug in XLR or phone plug ins and outs, and you’re wired.
The phone and XLR Input jacks are differential. At the output, only the XLR is differential (balanced). The output phone jack
tip is wired to pin 2 of the XLR out, and therefore is in phase with that pin. The only possible problem is if you attach one of
the XLR output pins 2 or 3 to ground. A separate amplifier drives each of these pins, so grounding one of them will short the
associated amplifier out. Therefore if you only use pin 2 on your output cable, leave pin 3 floating (unconnected) and vice
versa. The phone jack ins and outs will be out of phase with pin 3 since the unit is wired pin 2 hot from the factory (see note
below). Pin 1 should almost always be grounded on the XLR cables, but there are times where a buzz can be introduced
thru chassis grounds.
Note: It is possible to change the wiring of the connectors inside since they are hand wired. A user can therefore make XLR
pin two or three hot in relation to the phone jacks. Always unplug unit before making any changes. Our company cannot be
responsible for damage to unit or electric shock to anyone trying any modifications.
STEREO OPERATION & 5.1 SURROUND USE
To put the FATSO into Stereo mode, press both COMP buttons simultaneously, or in older units, press both WARMTHS.
The orange link LED will lite on both channels. Let up on both buttons simultaneously. There are two main link effects:
1) The compressors are linked and their gain reduction will match, provided both are enabled. 2) The “Bypass” and COMP
controls now controls both channels. It is usually best to match all front panel knob and switch settings on the two “left
and right” units to maintain imaging. However, unlike most units, the user has the option to treat the left and right channels
differently by using the old link (Pressing both Warmths simultaneously). This allows “hybrid” compressors. The new FATSO
EL7x adds the new COMP link, making either channel control the functions, but also provides the older Link (press both
WARMTHs (instead of both COMPS) which enables different compressors on the two channels. Sometimes for room mics,
keeping the units unlinked actually makes them sound more stereo.
For 5.1 surround where multiple units must be locked together, chain one unit to the next with a short phone plug cable in the
“External Link” jacks, match controls, and put units in “Link” mode. Two interchangeable “External Link” jacks are provided
to go to and from each FATSO. The gain reduction will now match on all units linked this way. For standard 5.1 processing,
three FATSOes will be used.
The compressor bargraphs on the bottom will indicate that the two channels are responding together. Due to the high
resolution of the bargraph there may be slight differences in the left/right bargraph response, mostly on the first few LED’s
(i.e. 1dB, 2dB, 3dB of gain reduction). New FATSOs (the EL7x) match better.
A NOTE ON BYPASS AND THE MULTIPLEXED CONTROLS
Multiplexed controls allowed us to fit everything into a 1.75” height chassis, with color-encoded indicator LED’s arranged in
an easy to read pattern, with Red LED’s usually indicating more radical or distorted settings. To change compressor types,
Warmth threshold, and the TRANNY/bypass, press the associated button and cycle through the options. To compare two
close settings, hold the associated button for one second to step backwards. Press briefly again to go to first setting. The
FATSO uses a hardwired bypass relay enabling the user to compare processed and unprocessed signals accurately. When
comparing the original signal from the processed signal, matching the output level with bypassed signal makes it very easy
to hear the processing changes. The bypass on the FATSO is multiplexed with the TRANNY control, and on the NEW “x”
version, holding the TRANNY/Bypass button will step backwards, allowing a one button press to “Bypass” from any state.
FATSO PET TRICKS
1) You can alter the standard thresholds of the FATSO by inserting a level control in the Sidechain point. By turning
the gain down there, the threshold will move higher, elevating operating distortion. Adding gain there will lower the
threshold and lower Distortion/Saturation. See our website for more information. www.EmpiricalLabs.com
2) It is also possible to make the FATSO have frequency dependant compression using the Sidechain insert Jack
(was previously labeled INSERT on older FATSOs). Send the tip of the Sidechain jack to an EQ, and return EQ to the
ring. The sidechain must not have appreciable delay nor be out of phase since it will affect the response time and
possibly comb filter the control signals when in Stereo.
3) To set quick +4 tape levels, try setting output at 7.5 and “drive” input knob until compression occurs.
For –10 input devices start at 5.5 to 7 output level.