True to the Music
Radial Engineering Ltd. Workhorse User Guide
16
CARD-EDGE CONNECTOR SPECIFICATIONS
The following details the pin confi guration as used in the Workhorse. The ‘Old’ refers to the published API/VPR specifi cations. The ‘Current’
refers to the various racks we have investigated on the market. The ‘New’ is the Radial standard as outlined in the Workhorse Open Source
Document.
Pin # Old API Specifi cation Current use in market New Radial Specifi cation
1 Chassis Ground Chassis Ground Chassis Ground
2 Output +4dB Hot Output +4dB Hot Output +4dB + Phase
3 Output -2 Hot - - - - - -
4 Output Cold Output Cold Output +4db - Phase
5 A- Ground A- Ground Analog Ground
6 Stereo link Stereo link Stereo link
7 Input -2 Cold - - - ¼” TRS Omniport - Ring
8 Input +4dB Cold Input +4dB Cold Input +4dB - Phase
9 Input -2 Hot - - - ¼” TRS Omniport - Tip
10 Input +4dB Hot Input +4dB Hot Input +4dB + Phase
11 Gain adjustment - - - Radial Buss feed
12 +16VDC supply +16VDC supply +16VDC supply
13 Power Ground - 0V ref Power Ground - 0V ref Power Ground - 0V ref
14 -16VDC supply -16VDC supply -16VDC supply
15 +48VDC Phantom +48VDC Phantom +48VDC Phantom
Due to the lack of clear standards, we have worked within the
limitations of keeping the old standards while making the Workhorse
as fl exible as possible. For instance Pin-3 has been left open
because sometimes (on some modules) it is paralleled with Pin-2.
This arrangement eliminates problems between other modules. We
also discovered that sometimes Pin-7 and Pin-9 can be paralleled
with Pin-8 and Pin-10, so the Omniport™ jack will not interfere.
The BUSS FEED (Pin-11) is simply whatever signal the designer
will want to send to the buss (main out of module typically) and is
essentially an amplifi er feeding a 4K7 resistor to Pin-11. That is
connected to the inverting (virtual earth) input of an op-amp (in the
mix section of the rack) with a 4K75 feedback resistor. This is called
a ‘Virtual Earth Mix Buss”. It is low noise and less prone to problems.
We chose 4K7 because it is lower noise than a higher value and
because the Rupert Neve Designs Portico series has a 4K7 Mix
Buss on all of their modules. This provides cross-compatibility
between Radial and Rupert Neve Designs.
The BUSS output on Pin-11 of each Radial module connects to a
level and pan control in the master mixer area. By being able to
mix together the output of what may be several modules in series
various new effects may be created. For example if the Phazer phase
adjustment tool is in a series chain of modules, it can be used as a
radical EQ to phase cancel the tone by creating a nulling effect.
Pin #
1 Channel 8 Hot
2 Channel 8 Ground
3 Channel 7 Cold
4 Channel 6 Hot
5 Channel 6 Ground
6 Channel 5 Cold
7 Channel 4 Hot
8 Channel 4 Ground
9 Channel 3 Cold
10 Channel 2 Hot
11 Channel 2 Ground
12 Channel 1 Cold
13 Not Used
Pin #
14 Channel 8 Cold
15 Channel 7 Hot
16 Channel 7 Ground
17 Channel 6 Cold
18 Channel 5 Hot
19 Channel 5 Ground
20 Channel 4 Cold
21 Channel 3 Hot
22 Channel 3 Ground
23 Channel 2 Cold
24 Channel 1 Hot
25 Channel 1 Ground
+
1
-
+
G
-
+
G
2
3
-
+
G
-
+
G
4
5
-
G
-
6
7
-
+
G
-
+
G
8
13
14
25
1
Pin #
1 Channel 8 Hot
2 Channel 8 Ground
3 Channel 7 Ground
4 Channel 6 Hot
5 Channel 6 Ground
6 Channel 5 Ground
7 Channel 4 Hot
8 Channel 4 Ground
9 Channel 3 Ground
10 Channel 2 Hot
11 Channel 2 Ground
12 Channel 1 Ground
13 Not Used
Pin #
14 Channel 8 Ground
15 Channel 7 Hot
16 Channel 7 Ground
17 Channel 6 Ground
18 Channel 5 Hot
19 Channel 5 Ground
20 Channel 4 Ground
21 Channel 3 Hot
22 Channel 3 Ground
23 Channel 2 Ground
24 Channel 1 Hot
25 Channel 1 Ground
+
1
+
GG G G
+
G
2
3
+
G
+
G
4
5
G
+
GGGG
6
7
+
G
+
G
G
G
8
13
D-SUB CONNECTOR FOR UNBALANCED
SUMMING MIXER INPUT
D-SUB CONNECTOR FOR CARD SLOT I/O
1
2
3
4
5
-16VDC
COM
+48VDC
+16VDC
COM
CONNECTOR WIRING
HOT (+)
COLD (-)
GROUND
1
2
3
HOT (+)
GROUND
COLD (-)
XLR Connector
TRS ¼” Phone Connector
5-Pin XLR Power Connector
