Gain Control - YORKVILLE Power MAX Manuel De L'utilisateur


BAL LINE Inputs
Mono line-level sources, e.g. amplifier line ouputs and high-impedance mics, can be connected to the
mono or stereo channels via these jacks (use the L / MONO jacks on the stereo channels). Stereo tape
decks and CD-players may be connected to the BAL LINE inputs on the stereo channels. RCA connec-
tors are also provided to simplify this operation. It is possible to connect stereo sources to the mono
channels, however you will need to plug the L&R signals into separate channels to avoid the risk of
intermodulation distortion (i.e. do not "Y" them into one BAL LINE jack).
• The balanced connector references are: Tip (or XLR pin 2) = hot, in phase; Ring (or XLR pin 3) =
hot, reverse phase; Sleeve (or XLR pin 1) = ground
You may connect an unbalanced source to any of the BAL LINE inputs with a regular unbalanced
shielded patch cable. A slight modification to a balanced patch cable will help achieve noise cancella-
tion when connecting POWERMAX to an unbalanced unit.
Simply undo one end of a balanced patch cord and de-solder the wire from the ring tab, then resol-
der the wire to the shield tab making sure that it does not touch anything else. Now re-assemble the
plug and mark it with some tape for future reference. This will be the end that you plug into the unbal-
anced unit (this will also work with an RCA connector).
The L & R BAL LINE inputs on the STEREO channels are wired together internally so that a single
(mono) signal connected to the L / MONO input will also be patched over to the R input (as long as
nothing is plugged into the R jack). This simplifies connecting a mono source should the need arise
(perhaps all the mono channels are taken).
In addition to being able to connect either a stereo or mono source to these jacks, you may alternate-
ly connect two different mono sources to them and use the BALANCE control to regulate their relative
volumes. For example, a guitar amp line-output and a keyboard amp line-output could be connected
and mixed this way. However, now you must also convert the POWERMAX to mono operation, other-
wise one instrument will only come out the left speakers and the other only through the right speakers.
Mono conversion is accomplished simply by plugging a "Y" patch cable from the L / MONO (left main)
LINE LEVEL OUTPUT to the AMP A & B AMPLIFIER INPUTS. Now both main power amps will be
receiving identical signals. See under PAN Control for another user tip regarding mono operation.
CD/TAPE Inputs (Stereo Channels Only)
These RCA connectors are included for convenience since many CD-players and tape decks have RCA out-
puts. Because it is primarilly a live audio mixer, POWERMAX does not have an RIAA phono input circuit.
As a rule you would connect a tape deck or CD-player to either the CD / TAPE inputs or the 1/4"
BAL LINE inputs, but not both. However, connecting sources to both sets – say, a tape deck to the CD/
TAPE inputs and a CD-player to the BAL LINE inputs on the same channel – will work. Naturally there
will not be any separate level control for one or the other so the source with the strongest output signal
or highest output impedance will be louder. If you are not running both sources at once, this won't be
a problem. In any case there will be no loading distortion or other ill effects.
HPF Button
Situated at the top of the mono channel strips, this button switches a High-Pass Filter in and out repre-
senting a bass rolloff of 18dB per octave below 80Hz. The stereo channels do not have this feature, as
they would usually be carrying recorded material.
The HPF (High-Pass Filter) is useful for controlling unwanted low-frequency spillover pickup by mics
located too close to the bass drum, bass amp or the keyboard amp. It is also effective in regulating acous-
tic guitar pickups that are too boomy sounding (the lowest note on a concert-tuned guitar is 81.2Hz, so
you aren't losing anything by rolling off the input response below 80Hz). Additionally, the HPF works to
reduce pops and thumps from vocal mics. In fact, Any mic or pickup which reflects a source that does
not go below 80Hz should have the HPF activated. This includes most wind instruments, most male voic-
es, nearly all female voices and all drum mics except for kickbass. Why roll off the bass on these chan-
nels? ...because you will obtain added clarity and improve the system's gain before feedback.

GAIN Control

POWERMAX features active input circuitry with exceptionally high headroom. The GAIN control regu-
lates the channel gain level to match it with the input signal strength. There are two gradation circles, the
outer one (minus 20dB to plus 56dB) for the MIC input, the inner one (minus 36dB to plus 40dB) for the
BAL LINE input. Since this control has a range of 70dB, it presents the user with considerable variability
given the slightest amount of movement. You may need to become familiar with this aspect of the mixer.
A quick way to ensure that the GAIN is adjusted correctly is to turn it up during a sound check until
the CLIP LED begins to flash (keep the channel fader at a safe, low setting during this process), then
turn the GAIN down slightly. POWERMAX's CLIP LED drive circuits are preset to fire at -6dB below
the onset of actual clipping so you need not worry about seeing some activity on the lights. You will
find that this or any system performs more cleanly and quietly with the GAIN controls all set properly.
Also, you may use PFL (Pre-Fade Listen) and the VU meter to set 0dB.