Whirlwind MIX-5S - Manual (Page 2)

Block Diagram:
Right channel sections and pan pots apply only to the Mix 5 Stereo.
THEORY OF OPERATION
All of the XLR and 1/4” input and output jacks are
active, electronically balanced circuits. The input
section and all critical gain sections of the Mix 5 use
the same IC for gain as top professional mixing
boards. This IC, along with careful component
selection and PC board layout, enables the Mix 5 to
achieve professional quality signal reproduc tion. All
the gain controls o n the Mix 5 (Channe l Gain, Aux
and Master) have a range of -60 to +20dBm. With the
input and output switches in the L ine position and
both the channel and master volume controls at the
same settings, u nity gain is approximately at the 9
O’clock knob position, 10dB gain at 12 O’clock, and
15dB gain at 3 O’clock. At the 5 O’clock position the
unit provides 35dB of gain. The Mic position of the
input switch provides another 20dB for a total of
55dB of gain. This feature allows the Mix 5 to
adequately mix equipment with a wide range of audio
level outputs. 60dB of attenuation in the Off position
allows the Mix 5 to adequately “turn off” line level
signals at the Mix 5 inputs.
The output sectio n of the Mix 5 was d esigned to
accommodate any configuration – line or mic level;
XLR or ¼”; balanced or unbalanced. Each channel’s
output jacks are i ndividually b uffered so that usi ng
any combination of the outputs at any impedance will
not affect the other outputs. With the Mic/Line switch
in the Mic position, the XLR output is reduced 20dB
(this switch does not affect the 1/4” jacks). The Mix 5
uses an H-Pad resister network at the XLR to
maintain the signal to noise ratio, regardless of the
position of the Mic/Line switch. For the XLR
outputs, if ground lifting of pin 1 is desired, jumpers
JMP 84 and JMP 85 inside the unit can be clipped.
Then, in Line mode pin 1 of the XLR is completely
lifted and in Mic mode the XLR’s pin 1 is ground
isolated and referenced to pins 2 and 3. If unbalanced
operation is desired from the XLR outputs, pin 2 is
hot, pin 1 is ground, and pin 3 should be left
UNCONNECTED.
The Mix 5 utilizes a dual primary power transformer
that is configured with internal jumpers for 120 VAC
60Hz or 230 VAC 50Hz operation. There is an
internal fuse on t he hot side of the AC cord, and the
power switch make s and breaks bot h the hot and
neutral legs of the AC cord.