Oakley Multimix – OMS-902 – Rev 7/8/02

1U implementation to match the 1U Stooge panel

I have been asked several times about the normalizing scheme that Dave Bradley
and I used for the 1U panel implementation of the Oakley Multimix PCB. Here is
the specific PCB to I/O jack hook up information. I will add some photos soon.

Here we go (assuming standard MOTM 112A jack orientation):
Here is the hook-up for the original issue 1 Multimix (issue 2 farther down)

Issue 1-Input side:
1 IN jack bevel to PCB 1 IN ground (left, nearest pot)
1 IN jack top no connection
1 IN jack left to PCB 1 IN hot (right)
1 IN jack left to 2 IN jack top (the switch)
2 IN jack bevel to PCB 2 IN ground (left, nearest pot)
2 IN jack left to PCB 2 IN hot (right)
2 IN jack left to 3 IN jack top (the switch)
3 IN jack bevel to PCB 3 IN ground (left, nearest pot)
3 IN jack left to PCB 3 IN hot (right)

You will notice that both A and B left lugs have 2 wires each. What this
does: The A signal is cascaded down to B and C so this can be a 1 in 3 out
multiplier. As soon as you plug something into B or C that input takes
over. Of course, B alone can cascade to C.

Issue 2 - Output side (more tricky):
1 OUT jack bevel to PCB "SCRN" near power connector
1 OUT jack top to PCB 1 OUT (left, nearest pot)
1 OUT jack left to PCB 1 OUT (right)
2 OUT jack bevel to PCB "SCRN" near power connector
2 OUT jack top to PCB 2 OUT (left, nearest pot)
2 OUT jack left to PCB 2 OUT (right)

Careful here:

ON PCB, do not connect any jacks to OUT 3. Instead connect a short jumper
between the two pads for out 3.
ON PCB, do not connect any jacks to "- OUT" Instead leave these totally
unconnected.

3 OUT jack bevel to PCB "OUT" ground (left connection, near C16).
3 OUT jack top NO connection.
3 OUT jack left to PCB 2 "OUT" hot (right connection, near C16).

Here is what this does for you. If nothing is plugged into # 1 or # 2
output, their signals are carried back to the mixer. So, for 3 inputs, # 3
is your mix out. As soon as you plug something into # 1 output, that signal
is excluded from the mix out. So, if you had all 3 inputs, and plugged 1
and 3 out, channel # 1 would be a plain reversing attenuator 1 IN to 1 OUT,
2 and 3 are now mixed and appear at 3 OUT. Then if you also plug something
into # 2 output, that signal is also excluded from the mix out. So, if you
had all 3 inputs, and plugged 1, 2 and 3 out plugged, each channel would be
a plain reversing attenuator 1 IN to 1 OUT, 2 in to 2 out, 3 in to 3 out.

So in this configuration this module can be a 1 in 3 out multiplier, 3 IN 1
out mixer, 3 separate reversing attenuators, or various combinations of
those 3 all depending on how you connect it.

Omit resistor R73 since you are not using the (-) out
Omit resistor R66 if you don't use the LED
Omit resistor R79 if you do not use the carry in.

Issue 2:

I have not yet built an issue 2 Multimix. But, I have my PCB. And, thanks to Gary
Speiker who has built and tested his, I can report the connections for the issue 2
PCB as follows:

Issue 2 - Input side:
1 IN jack bevel to SCRN
1 IN jack top no connection
1 IN jack left to PCB IN-1

1 IN jack left to 2 IN jack top (the switch)
2 IN jack bevel to SCRN
2 IN jack left to PCB IN-2

2 IN jack left to 3 IN jack top (the switch)
3 IN jack bevel to PCB SCRN
3 IN jack left to PCB IN-3


You will notice that both A and B left lugs have 2 wires each. What this
does: The A signal is cascaded down to B and C so this can be a 1 in 3 out
multiplier. As soon as you plug something into B or C that input takes
over. Of course, B alone can cascade to C.

Issue 2 - Output side (more tricky):
1 OUT jack bevel to PCB SCRN
1 OUT jack top to PCB IN-A

1 OUT jack left to PCB OUT-1
2 OUT jack bevel to PCB SCRN
2 OUT jack top to PCB IN-B
2 OUT jack left to PCB OUT-2

Careful here:

ON PCB, do not connect any jacks to OUT 3. Instead connect a short jumper between the two pads OUT-3 and IN-C.

ON PCB, do not connect any jacks to "- OUT" Instead leave these totally unconnected.

3 OUT jack bevel to PCB SCRN
3 OUT jack top NO connection.
3 OUT jack left to PCB "+OUT"

Issue 2 is identical in functionality as described above in issue 1.

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