9
!
Q: No Power, No Indicators ?
Ensure the IEC plug at the rear of the unit is inserted all
the way. Wait at least five minutes before trying the power
switch again. If the unit does not power up then check the
fuse on the PSU. (See Servicing, Diagram 3)
Q: The Unit Is Switched On, No Sound ?
First try plugging the IN and OUT cables into some other
piece of gear to verify that your cables are OK. Next check
the front panel, try BYPASS. If you have sound now it might
be a good idea to turn up the output levels to about 1
o’clock (rather than fully counterclockwise which is “minus
infinity”.
Q: Levels Seem To Be Wrong, No Bottom ?
Several possible scenarios. Manley uses the professional
standard of +4 dBm = Zero VU = 1.23 volts AC RMS. A lot of
semi-pro gear uses the hi-fi reference of -10 dBm = Zero
VU. This is a 14 dB difference that will certainly look odd
and may tend to distort. Often there are switches on semi-
pro gear to choose the pro reference level. We do not
provide that kind of switch because of inevitable
compromises in the signal path. If the loss looks close to 6
dB and it sounds thin then one half of the signal is lost. The
cause is probably wiring again. One of the two signal
carrying wires (the third is ground / shield on pin 1) is not
happening. Check the cables carefully because occasionally
a cable gets modified to work with a certain unit and it
seems to work but its wrong in other situations. If only one
side of the ELOP+ exhibits this problem, it may be a
problem in the unit itself.
Q: Only One Channel Is Functioning ?
This may be due to a faulty tube. This is a two channel
unit, meaning you can swap tubes to determine the faulty
tube. Switch one tube at a time, ensuring you place the
correct tube in the correct base. You can swap VT1 Left
with VT1 Right. Do not put VT1 in VT2. The 5751 and 6922
tubes have different pin connections. Leave the unit
switched off for at least 15 minutes before removing any
covers. If upon examination you see a white topped tube
instead of a silver top, this tube is likely to have cracked
its glass envelope, fracturing the vacuum, this tube will
need to be replaced.
Q: How Can I Cure Low Frequency Hum?
Method 1
- The most likely cause is a ground loop. This can
be cured by lifting the chassis to signal ground lift jumpers
which are located inside the unit. Please refer to the
Servicing Chapter, Diagram 3.
Method 2
- Cutting the shield on one side of the cable (PIN
1). This is done by some studios at every female XLR to
“break” all loops. You may get a loop simply from the
rack. All the other gear in the rack is “dumping” ground
noise onto the rack rails. Try removing the ELOP+ from the
rack so that it is not touching any metal. You may have
cured a non-loop hum. Some gear radiates a magnetic field
and some gear (especially if it has transformers) might
receive that hum. The unit would have to physically be
moved away from any highly radiating power supply in
order to cure this type of induced him.
7. Questions & Troubleshooting
Method 3
-Another method of reducing all sorts of hum and
noise is to use a 60-0-60 balanced AC power transformer.
Hum is more likely with the unbalanced inputs and outputs
because these signals are ground referenced. A common
situation is using the ELOP+ in a way that significantly
boosts the low level signals and what may have started out
as a little hum becomes nasty. Check out the gear feeding
the ELOP+ or use less limiting and make-up gain.
Q: Why is my ELOP+ Not Completing its Power-Up Cycle?
The ELOP+ utilizes a custom designed, sophisticated high
voltage switched-mode power supply. This power supply
features protection circuitry to stop any damage being
caused to itself. If at anytime the unit will not power-up
the protection circuitry may have been triggered. It is in
protection mode if after switch-on the power LED blinks for
a fraction of second then after a pause it blinks again. The
PSU is now in protection mode as the supply is trying to
reset. This condition will occur if the unit suffers excessive
heat exposure or there is a damaged tube or component.
Allow the unit to cool and try powering-up again. If the
protection mode persists, the unit will have to be returned
for service.
Q: ELOP+ Makes Noises When The Front Panel Is Tapped?
Some tubes become microphonic over time. That means
they start acting like a bad microphone. Vibration and aging
has caused the supports for the small internal parts in the
tube to loosen and now the tube is sensitive to vibration.
The only remedy is to replace the tube.
Q: I am Hearing a lot of Hiss?
This is again a common tube symptom. You could swap
tubes to find the culprit but an educated guess is OK too.
Generally the first tube in the path is the one with the most
gain and dealing with the softest signals. VT1 (5751) is the
first tube in the signal path. (See Servicing Chapter,
Diagram 3)
Q: ELOP+ Sounds Distorted?
This might be a tube. Swapping is a good way to find out. It
may be a wiring issue or mismatch. Wiring problems usually
accompany the distortion with a major loss of signal.
Mismatches are a bit tougher. The ELOP+ has a high input
impedance (HI Z) but some gear has a reasonably low input
impedance. Without even explaining the term “impedance”
it is enough to say that a lot of gear is simply not capable of
driving pro levels and low impedances. It will sound like lost
headroom, early clipping, distortion on peaks. Often
changing the order of processors will do the trick. Also
check your patch bay in case there is a problem there too.
