sonolink

Help with Modding a Talk Back Switch
« on: September 22, 2020, 07:48:54 PM »
Hello everyone,

I recently repaired a Mackie Big Knob thanks to the help and advice of people here, and have been able to give the unit to a friend as a gift for his studio. The unit has an integrated TBack system that is quite ok. The only drawback is that the switches to activate it are momentary. The unit also has a footswitch jack connector to use the TBack system.

So, my first idea was to see if it's possible to substitute the momentary button switches with latching ones, but when I realized there was a footswitch jack connector I thought of building a little box with a latching switch that can be placed in a convenient spot around the desk, connected to the footswitch jack connector. So I found some nice looking switches that have an integrated LED.

My question is: how would you guys feed the LED? Battery in the box? Replacing the footswitch connector with a stereo connector to run DC through it too? (if that's possible at all)
Any ideas are very welcome.
This is the original schematic of the adaptor:


Thanks in advance for your time and help
Cheers
Sono
Why sleep when you can mix?
M.P.Stavrou


boji

Re: Help with Modding a Talk Back Switch
« Reply #1 on: September 23, 2020, 02:07:37 AM »
Sorry, why would you want indication at foot level that as well gives audible indication at speaker level?

Edit: Misread. You want a indicator light on desk, changed by footswitch on floor, and it all be removable via instrument jacks?
 
Tap off incoming DC to 1/8" female trs or mono for led+resistor loop. Personally I'd use 24-4 data cable.
« Last Edit: September 23, 2020, 03:29:58 AM by boji »

Brian Roth

Re: Help with Modding a Talk Back Switch
« Reply #2 on: September 23, 2020, 02:16:53 AM »
Reminds me of a literally "sticky situation" from decades ago!

MCI desk with a failing talkback "talk to the cue bus" switch that was sticking in the "on" mode.

While the producer was dissing the performer/performance, it went out over the cue system to the hapless artist.  OOPS!

hence, no latch-on TB switch in my world ever since!

Bri

Brian Roth Technical Services
Salina Kansas, home of the best vinyl on the planet!

http://www.BrianRoth.com
recordingservicesandsupply.com/
www.qualityrecordpressings.com/
store.acousticsounds.com

boji

Re: Help with Modding a Talk Back Switch
« Reply #3 on: September 23, 2020, 02:58:45 AM »
Quote
hence, no latch-on TB switch in my world ever since!

Internets have had the same effect on me.  =D

sonolink

Re: Help with Modding a Talk Back Switch
« Reply #4 on: September 23, 2020, 04:16:07 PM »

Tap off incoming DC to 1/8" female trs or mono for led+resistor loop. Personally I'd use 24-4 data cable.

Thanks for your input Boji, but excuse my language barrier: I'm not sure I understand what you mean by "or mono for led+resistor loop."

Using a TRS would the pinout be i.e.: tip=audio, ring=DC, sleeve=GND?

Thanks for your help
Cheers
Sono
Why sleep when you can mix?
M.P.Stavrou

boji

Re: Help with Modding a Talk Back Switch
« Reply #5 on: September 23, 2020, 05:44:34 PM »
Mono or TS has two connection points, the minimum you'd need for sending DC to a switch, led & back to ground. Talkback would get the same type of loop with its own pair of wires for the footswitch.

Draw a diagram and share it here if you're having trouble.

sonolink

Re: Help with Modding a Talk Back Switch
« Reply #6 on: September 23, 2020, 08:34:00 PM »
So I'd need 4 terminals, right? 
2 for the TB switch as in the pic I posted previously and 2 for the LED circuit.
If that's correct, how do you do that with a TRS or a TS connector?
Sorry again if I'm not understanding something obvious you are telling me.  :)

Cheers
Sono
Why sleep when you can mix?
M.P.Stavrou

boji

Re: Help with Modding a Talk Back Switch
« Reply #7 on: September 23, 2020, 10:15:20 PM »
Quote
So I'd need 4 terminals, right?
Without knowing more about the TB circuit, correct.
4 terminals, two pole switch.

Quote
If that's correct, how do you do that with a TRS or a TS connector
Draw up what you think will work and post it here.


 

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