More troubleshooting – Manley The WAVE DAC/Preamp 24/96 Version Serial Code WAVE016-present 2002 - present User Manual

Page 18

HUM: Once again - several possibilities - several cures. Most likely it is a ground loop. Ideally each piece of gear should have
one ground connection and only one. However, the short list of grounds include the AC mains plug, the chassis bolted to a rack
with other gear, each input and each output. The two most common procedures are: try a 3 pin to 2 pin AC adapter (about a dollar
at the hardware store).This while legal in many countries can be dangerous- We went one better; Method two - On the back panel
loosen the GROUND TERMINALS and slide the wire ground strap to one side. This is way better than "method one" because
it is safer and removes another possible source - the chassis grounding via the rack. Method three - cutting the shield on oneend
of each cable. This is done by some studios at every female XLR to "break" all ground loops. All the other gear in the rack is
"dumping" ground noise onto the ground. Try removing the WAVE from the rack so that it is not touching any metal. You just
may have cured a non-loop hum. Some gear radiates a magnetic field and some gear (especially if it has audio transformers) might
receive that hum. A little distance was all it took. The balanced XLR outputs are very useful for feeding amps at some distance
which is often a easy way to set up a nasty hum. You can also experiment with disconnecting PIN 1 (shield) at EITHER end of
the interconnect. Given today's audiophile cables, this may not be possible but one can disconnect PIN 1 of OUTPUT 3 (or the
inputs) inside the WAVE as an experiment with probable success. And lastly sometimes adding more ground links between
system components actually helps. Take a bare wire and touch it between various preamp and source chassis in your system to
see if it will help. If so, then get those two chassis linked together with a grounding wire.

IT MAKES NOISES WHEN THE FRONT PANEL IS TAPPED: An easy one. Some tubes become microphonic over time.
That means they start acting like a bad microphone. Vibration has caused the supports for the little parts in the tube to loosen
and now the tube is sensitive to vibration. You can expect some amount of microphonics from all but the most elite superman
tubes... most all tubes will exhibit some degree of microphony. If it is too much for you then replace the tube. Which one? The
one that makes the most noise when you tap it. Usually this will be one of the smaller (gain stage) tubes closest to the front. The
WAVE will have to be on, connected to your amps and speakers in a normal listening mode in order to listen to tunes and/or
to listen for microphonics. If you have a ton of gain in your amps or subsequent preamplifiers following your WAVE, your
problems will be worse. De-Gain that system.

IT GOT HISSY: Damn snakes.... 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. The usual
suspect is the shorter tubes - the 12AX7 in the preamp. You may find that you need to choose the quietest tube out of several of
that type - like we do at the factory.

DISTORTION: This might be a tube. Swapping is a good way to find out. It may be a wiring thing or mismatch as well. Wiring
problems usually accompany the distortion with a major loss of signal. Mismatches are a bit tougher. The WAVE has a high input
impedance and low output impedance that can drive 600 ohm inputs of vintage "style" gear. The first things to suspect would
not be the WAVE, but the sources and especially the speakers which do fatigue and seem to be statistically most prone to those
kinds of symptoms. Start out by checking other sources and use the L/R swapping technique to locate the problem. If the WAVE
does seem to be distorting, then it is probably related to the load it is driving especially if it being asked to drive several sets of
amplifiers at once or a very low input impedance device.

DC OR SOMETHING AT THE OUTPUT THAT IS INAUDIBLE: The RCA unbalanced outputs have a frequency response
that goes way down to below 1 Hz. A little very low frequency noise may be seen as speaker movement when power amps are
sensitive. The XLRs do not exhibit this because the transformers filter below 8 Hz. Also the unbalanced outputs do not like high
capacitance cable. Figure out how much capacity you are trying to make the WAVE drive by measuring your cables with a
capacitance meter or by knowing the capacitance per foot of your cable (usually expressed in picofarads which is 0.000000001
of a Farad, or 10

-9

) then multiplying by how many feet the length is. Occasionally a very high frequency oscillation (200 kHz

to 400 kHz) may occur if you are driving a high capacitance load, like a couple microfarads, and that's a lot. (A microfarad is
0.000001 of a Farad or 10

-6

) Once again use the XLR outputs. Problem solved.

THE METERS ARE OUT OF CALIBRATION: This really only applies for our Mastering clients who have chosen The
WAVE as their reference DAC that feeds the processing chain. In this situation, "calibration" means high resolution digital
meters and VUs where one can see less than a tenth of a dB calibration error. Usually, a little adjustment on the trimmers is all
that is required. We can also replace the motorized Volume control with a detented 24 position rotary switch which provides
extreme matching of left to right, or a pair of 10-turn trimmers instead of a big remote controllable pot. There's always other ways
to do things. Again, note: The INSERT outputs are not set up to be a particular level such as -10 dBu or +4 dBm. Instead, they
are just the last switch in a passive relay switching chain. The output will be the same as the selected analog source, and roughly
consumer level -10 dBu if a digital input is active (Digital Full Scale =

8.25

dBu = 2.00 Vrms).

THE VOLUME POT IS SCRATCHY: Probably not. Select a different source, scratchiness gone? The source related with the
scratchiness must have DC on its output. The input stage is all direct connected and DC will get passed to the pot which will
make it seem noisy. The fix has to be done at the source that is sending DC which polite well behaved gear is not supposed to
emit. If you have DC coming out of one of your source components, go yell at that manufacturer to get rid of it... If the offending
unit can not be repaired, a capacitor or a pair of capacitors can be added at the input jack in line with the signals. A good value
is 10 uF/63V and it should be a film type (like a Wima MKS4, MultiCap, etc) and not an electrolytic. Smaller values down to
1 uF can be used but may cause loss of CMRR due to tolerance issues, and will also result in a bit more phase shift in the extreme
LF (which is generally inaudible).

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