C 71-1215 - Wheatstone
3 INPUT X 6 OUTPUT HEADPHONE AMPLIFIER DESCRIPTION
OUTPUT 1 can be fed from either the HOST or GUEST input.
OUTPUT 2 – OUTPUT 6 can be individually fed from either
the CO-HOST or GUEST input. Rear panel switches S1-1
thru S1-6 provide source selection. If a source is driven
from a volume controlled output (HOST, CO-HOST only) or
the output volume is controlled by using a conventional audio
potentiometer, rear panel switches S2-1 thru S2-6 individually
fix the gain of each output to provide 0 dBu for a nominal input.
The PRE99-1215 Headphone Amp provides six
headphone output ports from three balanced stereo
inputs (HOST, CO-HOST, GUEST).
Rear panel switches S1-7 and S1-8 allow the input
sensitivity of the HOST and CO-HOST inputs to be
set to +4 dBu for fixed sources or -8 dBu for volume
controlled sources (+4 dBu @ fader maximum, 16 dB
in-hand gain). The GUEST input can be driven from
a +4 dBu fixed output source only.
The six stereo output ports (OUTPUT 1 - OUTPUT 6)
are 0 dBu nominal unbalanced signals which directly
drive any impedance headphones. Each output port
connects to a Headphone Panel (PRE99-1214-x)
using a standard straight-thru CAT5 data cable that
carries the stereo headphone audio as well
as volume control voltage from either a 10k
linear fader (PRE99-1191), which plugs into
a Jack Panel (PRE99-1214-1, or -2),
or a 10k linear rotary pot on a combined
1 2
Jack and Level Control Panel
Of f
(PRE99-1214-3, -4).
O
On N
Rear panel switches S2-7 and S2-8 apply offsets of -8, -16,
or -24 dB to all GUEST outputs, reducing the level for
inexperienced users.
Page 2 shows a typical application for the 3x6 Headphone
Amplifier and the PRE99-1215 specifications.
REAR PANEL DIP SWITCHES
Switch S1
3 4 5 6 7 8
1 - Amp 1 Source
2 - Amp 2 Source
3 - Amp 3 Source
4 - Amp 4 Source
5 - Amp 5 Source
6 - Amp 6 Source
7 - Input Level: Host
8 - Input Level: Co-Host
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8 O
N 1 2 3 4 5 6 7 8
S1
S2
Off
On
Host
Co-Host
Co-Host
Co-Host
Co-Host
Co-Host
+4 dBu
+4 dBu
Guest
Guest
Guest
Guest
Guest
Guest
-8dBu
-8dBu
Switch S2
Off On
1 - Amp 1 Level Ctrl
2 - Amp 2 Level Ctrl
3 - Amp 3 Level Ctrl
4 - Amp 4 Level Ctrl
5 - Amp 5 Level Ctrl
6 - Amp 6 Level Ctrl
7 - Guest Offset “A”
8 - Guest Offset “B”
Fader Fixed
Fader Fixed
Fader Fixed
Fader Fixed
Fader Fixed
Fader Fixed
0 dBu 16dBu
0 dBu 8 dBu
(24 dB Offset with both A & B set on)
3x6 HEADPHONE AMP BLOCK DIAGRAM
OUTPUT 1
(RJ-45)
Vol
Ctrl
INPUT SOURCES
1
2
3
4
5
6
7
8
Power Amp
INPUT
SOURCE
CONTROL
HOST L
=
=
=
=
=
=
=
=
Left Audio
Audio Ground
Fader Top
Fader Bottom
Fader Wiper
Fader Wiper
Audio Ground
Right Audio
HOST R
FADER CONTROL
INPUT ATTN. (HOST)
A/D
Conversion
FPGA
CO-HOST L
CO-HOST R
REAR PANEL
S1 & S2
DIP SWITCH CONTROL
INPUT ATTN. (CO-HOST)
GUEST L
GUEST R
INPUT
SOURCE
CONTROL
A/D
Conversion (x5)
5300 Kingsphone
Island Drive
• Mason, OH 45040 USA
1.252.638-7000
PACIFIC RESEARCH
&
513.459.3400
• fax: 513.459.5309 • www.gatesair.com
ENGINEERING
pre.com | [email protected]
e-mail: [email protected]
DESIGNS BY PACIFIC RESEARCH & ENGINEERING
OUTPUTS 2 - 6
(RJ-45)
1
2
3
4
5
6
7
8
Power Amp
Vol
Ctrl
THIS DOCUMENT APPLIES TO
PRE99-1215
FADER CONTROL
TITLE
Left Audio
Audio Ground
Fader Top
Fader Bottom
Fader Wiper
Fader Wiper
Audio Ground
Right Audio
INSTRUCTION SHEET, 3x6 HEADPHONE
AMPLIFIER AND HP CONTROL PANELS
DRAWN
SHEET
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RLM
1 OF 2
DATE
June 17, 2014
APVD.
DWG. NO.
71-1215
REV.
C
TYPICAL HEADPHONE AMPLIFIER CONNECTIONS AND SWITCH SETTINGS
In this example, the Host is also the board operator. The HOST level is
controlled by the Console Control Room Headphone fader (thus S2-1 is
set to ON). Since the HOST source is a -8dBu volume controlled output,
S1-7 is also set to ON.
REAR PANEL DIP SWITCH SETTINGS FOR THIS EXAMPLE
Switch S1
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
Of f
O
O
N 1 2 3 4 5 6 7 8 N 1 2 3 4 5 6 7 8
S1
There is one CO-HOST (S1-2 set to OFF) and four GUEST positions
(S1-3 thru S1-6 set to ON). Each of these positions has a level control,
thus the CO-HOST and GUEST outputs are all set for level-controlled
operation (S2-2 thru S2-6 are set to OFF). The CO-HOST comes from
a fixed +4dBu output, so S1-8 is set to OFF.
S2
1 - Amp 1 Source
2 - Amp 2 Source
3 - Amp 3 Source
4 - Amp 4 Source
5 - Amp 5 Source
6 - Amp 6 Source
7 - Input Level: Host
8 - Input Level: Co-Host
Off
On
Host
Co-Host
Co-Host
Co-Host
Co-Host
Co-Host
+4 dBu
+4 dBu
Guest
Guest
Guest
Guest
Guest
Guest
-8dBu
-8dBu
Switch S2
Off On
1 - Amp 1 Level Ctrl
2 - Amp 2 Level Ctrl
3 - Amp 3 Level Ctrl
4 - Amp 4 Level Ctrl
5 - Amp 5 Level Ctrl
6 - Amp 6 Level Ctrl
7 - Guest Offset “A”
8 - Guest Offset “B”
Fader Fixed
Fader Fixed
Fader Fixed
Fader Fixed
Fader Fixed
Fader Fixed
0 dBu 16dBu
0 dBu 8 dBu
(24 dB Offset with both A & B set on)
PRE99-1198
On/Off/Cough/
Talkback Panel
Since the CO-HOST and GUEST 1 positions are primary, Headphone Faders
are shown. The other Guest positions (GUEST 2, 3, and 4) use the PRE99-1214-3
or -4 panels which utilize a rotary potentiometer volume control.
PRE99-1191
Headphone
Fader
CO-HOST
TALK
BACK
PRE99-1214-1 or -2
COUGH
HOST (BOARD OPERATOR)
HOST / OPERATOR
CONSOLE
(STUDIO
OUTPUTS)
AMP
MOD IV
CO-HOST
RJ45
SCREW
TERMINAL
INPUTS
HOST
OUTPUTS
1
CO-HOST
GUEST
GUEST
2
3
4
50-22
DC
POWER
SUPPLY
85VAC
to 220VAC
50/60 Hz
ON
TO CONSOLE:
CO-HOST'S INPUT
CHANNEL LOGIC
CONNECTOR
POWER
PLUG INPUT
5
6
RJ45
OFF
80-1788-2
Two Position Cabinet Plate
PRE99-1214-1 or -2
RJ45
RJ45
AMP
MOD IV
RJ45
RJ45
PRE99-1197
On/Off/Cough
Panel
PRE99-1191
Headphone
Fader
RJ45
RJ45
GUEST 1
PRE99-1215
PRE99-1214-3, -4
COUGH
GUEST 4
RJ45
PRE99-1214-3, -4
GUEST 3
RJ45
TO CONSOLE:
GUEST 1 INPUT
CHANNEL LOGIC
CONNECTOR
ON
OFF
80-1788-2
Two Position Cabinet Plate
PRE99-1214-3, -4
GUEST 2
RJ45
RJ45
PRE99-1214-1 or -2
AMP
MOD IV
SPECIFICATIONS
GENERAL
Size: 1.75" x 19.0" x 7.25" Cabinet or rack (1RU) mounting
Weight: 3 lb
Power Supply: PRE50-22 "line-lump" with multi-pin connector
Supply Voltages: +5 and 615 VDC
AC Input: 85 - 220 VAC, 50/60 Hz
INPUTS
Type: 3 active inputs (balanced/unbalanced): Host, Co-Host, Guest
Connectors: plug-in screw terminal (Weco 110)
Nominal Impedence: 17k ohm
Nominal Levels: +4 dBu (Guest), +4 dBu or -8 dBu (Host & Co-Host)
Maximum Input Signal Level: +21 dBu (using +4 dBu setting)
Overall Gain Range: Off to +24 dB (using -8 dBu input setting),
+12 dB (using +4 dBu setting), no load
OUTPUTS
Connectors: RJ-45 jacks x6 (connect to PRE99-1214-x panels)
Output Impedence: 50 ohms
Headphone Impedence Range: 8 to 600 ohms
Power Output, single channel driven:
392 mW into 32 ohms, 379 mW into 100 ohms,126 mW into 600 ohms
Power Output, all six channels driven:
374 mW into 32 ohms, 379 mW into 100 ohms,126 mW into 600 ohms
Frequency Response: 3 - 60kHz, +0/-3 dB (unity gain)
THD + Noise: 0.0033% (378 mW into 100 ohms,1 kHz, 22 kHz BW, unity gain)
<0.05% (378 mW into 100 ohms, 20 - 20 kHz, 80 kHz BW, unity gain)
Signal-to-Noise Ratio: -93 dB (22kHz bandwidth, unity gain)
Output Signal Source: selected thru rear panel multiswitches
Output Level Control: Fixed or fader-controlled through PRE99-1214-x panels
PACIFIC RESEARCH &
ENGINEERING
phone 1.252.638-7000 | pre.com | [email protected]
71-1215rC, PAGE 2 OF 2
Quincy, Illinois 62305 USA · www.gatesair.com
Support: +1 217 222 8200 · [email protected]
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