How does the 911a connect to the 911’s
Regarding the trigger / envelope voltage panel
I know that the 3 lower right switches connect the 3 x 911’s to their respective 902’s
As for the left side switches, the top left I know is from keyboard S trig and second down is connected to 911 #1
But its the 3rd and 4th down I’m not sure about…I know they go to the 911a but in what way?
Do they simply connect the S-trig to the 2nd and 3rd 911 ..ie on/off?
Also are the slide switches on when slid up?
Are you asking about the Moog 993?
It is just a signal routing panel to eliminate patch cords. All of that routing could be done with patch cords. These connections are done via the rear 22-pin edge card connectors and wiring harness.
The top selects the S-trigger source, either Buss 1 or Buss 2. The advantage of S-triggers are they can be “OR” gates and one or both will trigger the routed 911A edge card input.
The left lower switches are the routing of the above selected S-triggers to the 911A and interconnected 911’s.
Top left takes the above selected S-triggers and routes this directly to the left 911 S-trigger from the 911A edge card input. (Same as a direct connection from the above selected switches to the left 911.) Center left routes the 911A top section output to the center 911 S-trigger input. (Delay from 1st section of 911A S-trigger.) And the bottom routes the 911A bottom output to the right 911. (Delayed from 2nd section of 911A S-trigger.)
The position of the 911A rotary switch will affect the right 911, since “series” will give a combined delay, “parallel” only the 2nd delay and “off” will not trigger.
The right section is almost just a simple 911 output to each 902. However these are connected via the 911 edge card output and via the 902 edge card input. This routes to the 902 input node and combines/mixes with the three front panel CV inputs. This connection requires a 100K resistor between the 911 output and 902 input node. So there are three 100K resistors, one for each 902 input node.
All switches are on/connected when up.
Never really thought this was the most efficent switching layout, but more of a tradeoff of available space with slide switches. Looks cool though!
Thanks CZ…thats cleared up my wiring now that I have my 911a installed. I needed confirmation as there are quite a lot of cables concerned if you don’t use edge connectors , in fact its quite a task making sure all are connected correctly, I use coloured labeled plugs at the rear of the panels …not Moog I’m afraid but works although I dont like the appearance.
CZ…I need a point clearing up…so is there an EXTRA 100k resistor
between the 911 and respective 902 or are these the three 1% 100k that are on the circuit board of the 902’s ?
An extra 100K, one for each 911 output to each 902 input node.
On the stock configured Moog systems the “Node” input is used. I guess the idea here is via the node input, one could add as many extra inputs by adding as many 100K resistors as needed for each extra CV input. So looking at the 902 schematics the node connects after the three 100K resistors from the panel jacks. By adding in the 100K inline at the node input, there are now four CV inputs, each with an equal 100K resistor to mix those four CV inputs equally together.
The 901A oscillator drivers use a similar input node, where four additional 1 volt per octave inputs are added via the routing switches below. Each of those switches has a 100K 1% resistor and is connected to the 901A input node. Same with the input nodes on the 904A and 904B. With the input node one can add extra inputs without loosing or giving up the few front panel inputs.
If you study the schematics the node inputs are located after the input resistors, and a convient place to add more inputs by simply adding resistors.
Just thought it was worth mentioning, since there aren’t any 993 schematics I’m aware of. The pinnouts can be seen on the large model 55 cabinet wiring diagram. It uses 16 of the 22 pins.
You can get a look at the inside from one that was auctioned off at VEMIA. Click on the photos for a better look. Not much to it, but you can see the three added 100K resistors.
Link to VEMIA auction for Moog 993
Thanks CZ…I get the 911a and switching panel now.
I did have the outputs from the 911s going to one of the 3 x 100 k resistors..now because of your info I now realise that was wrong…so I have the extra resistor to node…all working fine. Thanks once again.
I guess the original PCB edge connectors are long obsolete now ..Ive never seen any for sale anywhere.