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SSL AWS Tally Outputs
Old 29th June 2016
  #1
SSL AWS Tally Outputs

I am trying to use the tally output (TB All Tally) on an SSL AWS948 to turn on a red light. I was advised by SSL to use an external transistor and relay to switch the 12V supply to the red light, and I was given a sample circuit (attached).

I built up a circuit based, on the sample circuit, on a Radio Shack protoboard (schematic attached). The circuit works just fine using a bench supply sending 12V to power the transistor and the red light, and sending β‰₯0.6V to the base of the transistor to turn it on.

The circuit doesn't work using the console's tally output fed to the base, because the tally output is only putting out 0.585V, which isn't enough to turn on the transistor.

I was subsequently advised that, "...if you need to sink 40mA through the collector and you're sending half a volt to the base, referenced to the LED supply negative, try a 12 ohm resistor in place of the 1K. You could probably just remove the resistor all together with the same result." This doesn't make sense to me, as I would think that the base voltage needs to be at least 0.6-0.7V to get the transistor to turn on. And this works just fine on my bench at home.

I am thinking that the sample circuit that I was sent isn't appropriate for this application. The manual has a note below the pinouts for the GPIO connector (which includes the tally outputs) stating that "All tallies are open collector pull-down using a 47R series resistor"

This seems like it shouldn't be this hard, but my knowledge of electronics ranges from rudimentary to non-existent. Does anybody have any experience with SSL tallies? Or have an idea of what type of circuit I should be using to accomplish this? Or is the console just not putting out the correct signal? I was told it was a logic output, but I have never heard of a logic high state that is 0.585V. Something doesn't add up.

Thanks in advance for any help!!
Attached Thumbnails
SSL AWS Tally Outputs-sample-relay-driver-circuit.png   SSL AWS Tally Outputs-ssl-aws948-tallydriver-1d.png  
Old 1st July 2016
  #2
Well, in case anybody was wondering. I was given some incorrect information initially about the console's tally output. The tally output is an open collector output which consists of an internal transistor with the emitter connected to ground and the collector connected to the output pin with an internal series resistor. The relay is connected to an external power source and to the tally output. When the tally is switched on, the internal transistor is saturated which brings the collector close to ground and drops most of the external supply voltage across the relay, causing it to switch on. I attached a new schematic, which hopefully may be of use to somebody.
Attached Thumbnails
SSL AWS Tally Outputs-ssl-aws948-tallydriver-2a-opencollector-3.jpg  
Old 20th September 2016
  #3
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Good to hear you solved your problem. If you have any questions, feel free to ask me.

Currently I'm thinking of designing an easy to install interface for a recording light that is compatible with AWS and Duality consoles. Please let me know if anyone else is looking for such a solution.
Old 15th November 2019
  #4
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Quote:
Originally Posted by grmusik View Post
Good to hear you solved your problem. If you have any questions, feel free to ask me.

Currently I'm thinking of designing an easy to install interface for a recording light that is compatible with AWS and Duality consoles. Please let me know if anyone else is looking for such a solution.
Hi grmusik, yes...I have an AWS console and am looking to install a "Recording" light at the entrance to the studio that gets turned on when the console's record light goes red? Is this something you're still building?
Old 15th November 2019
  #5
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Good discussion. Do you guys know...in order to have a footswitch (ie. an M-Audio momentary/latching switch) control the TB of the console is it as simple as wiring the footswitch into the 0V and Ext TB Switch pins? So when the footswitch is pressed those two pins are connected?
Old 16th November 2019
  #6
Quote:
Originally Posted by swgerow View Post
Good discussion. Do you guys know...in order to have a footswitch (ie. an M-Audio momentary/latching switch) control the TB of the console is it as simple as wiring the footswitch into the 0V and Ext TB Switch pins? So when the footswitch is pressed those two pins are connected?
Yup. Easy as that. I wired it out to a female 1/4 connector so I could plug in the footswitch itself, or run an extender to get the footswitch to the client.

From the appendix in the manual:

"All switch inputs are active low (ie. connect to 0V to trigger)"


Also, make sure you use a NO (Normally Open) footswitch, or one with a switch to reverse it.

Last edited by originalscottyg; 16th November 2019 at 03:16 AM..
Old 20th November 2019
  #7
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Quote:
Originally Posted by swgerow View Post
Hi grmusik, yes...I have an AWS console and am looking to install a "Recording" light at the entrance to the studio that gets turned on when the console's record light goes red? Is this something you're still building?
Hi swgerow,

I did build a prototype to see if it works, but stopped there. There was no interest at all from other SSL owners, so I assumed there is no real need for such a device.

I even developed the idea a little bit further and call it a 'Producers Panel'. It duplicates the communication buttons on the console, has a talk back mic and a power outlet to plugin in a notebook or phone charger. And it also has an output for the recording light.
The idea was, to give the producer the opportunity to talk to the band while not sitting at the console. Giving the engineer some space to work comfortably.

If you need any advice or help, contact me. But I think it is too expensive, if I build this for you.

Regards
Greg
Old 21st November 2019
  #8
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Quote:
Originally Posted by grmusik View Post
Hi swgerow,

I did build a prototype to see if it works, but stopped there. There was no interest at all from other SSL owners, so I assumed there is no real need for such a device.

I even developed the idea a little bit further and call it a 'Producers Panel'. It duplicates the communication buttons on the console, has a talk back mic and a power outlet to plugin in a notebook or phone charger. And it also has an output for the recording light.
The idea was, to give the producer the opportunity to talk to the band while not sitting at the console. Giving the engineer some space to work comfortably.

If you need any advice or help, contact me. But I think it is too expensive, if I build this for you.

Regards
Greg
Thanks for the info. Sounds like it would have been a great idea!
Old 10th December 2019
  #9
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laperlestudio's Avatar
Hi Guys, did anyone found something interesting for a red light system for a Duality?

Thanks!
Old 27th May 2020
  #10
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@ laperlestudio
I was contacted by a studio that is also looking for a red light system. Let me know if you are still looking for a solution. If so, maybe you can team-up with them. This would lower the costs a little.
Old 28th May 2020
  #11
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laperlestudio's Avatar
Quote:
Originally Posted by grmusik View Post
@ laperlestudio
I was contacted by a studio that is also looking for a red light system. Let me know if you are still looking for a solution. If so, maybe you can team-up with them. This would lower the costs a little.
What kind of price are we looking into? Thanks!
Old 29th May 2020
  #12
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A calculation hasn't been done yet. I just started to collect information about the existing infrastructure and what functionality the studio needs. Feel free to send me some information about what you need.
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