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Re: Talkback Comp Build Thread

Posted: Tue Dec 10, 2019 8:45 pm
by mrclunk
I'm sorry Joe, i ment to update my post...
Mic worked fine using the standard (2 x 6k8) supply as on the pcb. It's an Astrada conference mic 952.353UK (just the gooseneck mic part)
All working nicely on our Calrec. I added a 1k Log pot across the output for volume and a cheap OEP a262a2e transformer to split the output.
One to the desk auxs and a separate out to patchbay for remote session down Skype etc.

Re: Talkback Comp Build Thread

Posted: Tue Dec 10, 2019 9:57 pm
by Joe Malone
mrclunk wrote:I'm sorry Joe, i ment to update my post...
Mic worked fine using the standard (2 x 6k8) supply as on the pcb. It's an Astrada conference mic 952.353UK (just the gooseneck mic part)
All working nicely on our Calrec. I added a 1k Log pot across the output for volume and a cheap OEP a262a2e transformer to split the output.
One to the desk auxs and a separate out to patchbay for remote session down Skype etc.
Cool great to hear you got it all working :-)

Re: Talkback Comp Build Thread

Posted: Sat Aug 22, 2020 12:28 am
by mrclunk
I have a slight issue with the TB amp.
I'm getting a loud pop when turning the TB on and off.
Is there a way to eliminate this?

Could it be DC on the relay contacts?

Re: Talkback Comp Build Thread

Posted: Sat Aug 22, 2020 9:49 am
by Joe Malone
mrclunk wrote:
Sat Aug 22, 2020 12:28 am
I have a slight issue with the TB amp.
I'm getting a loud pop when turning the TB on and off.
Is there a way to eliminate this?

Could it be DC on the relay contacts?
HI if built properly there should not be any dc on output. If getting pops make sure you are not sending phantom power into the output and there is no dc voltage leaking to the output xlr pin 2 & pin 3. Measuring with a meter from 0v to pin 2 and pin 3 will show if voltage is there or not. Try measuring with nothing plugged int the output first and then with it plugged in and let me know what find.

Re: Talkback Comp Build Thread

Posted: Mon Sep 20, 2021 2:55 am
by williard86
Couple questions:
1) any recommendations for a substitute for the ever hard to find 2n5457?
2) how can I have an adjustable threshold control? Coarse adjustment would be fine.
3) for an external gain control, would I need a reverse log 10k pot?

thanks

Re: Talkback Comp Build Thread

Posted: Tue Nov 09, 2021 10:01 am
by Joe Malone
williard86 wrote:
Mon Sep 20, 2021 2:55 am
Couple questions:
1) any recommendations for a substitute for the ever hard to find 2n5457?
2) how can I have an adjustable threshold control? Coarse adjustment would be fine.
3) for an external gain control, would I need a reverse log 10k pot?

thanks
HI Sorry completely missed this post

2n5457 is not that hard to find and would be a lot of work to get another type of fet to work in there.

Adding zeners or diodes in series with the threshold wires with vary the threshold level

Yes use 10k rev log pot for external gain

Re: Talkback Comp Build Thread

Posted: Tue Mar 01, 2022 10:48 am
by williard86
Hi thanks I found a few.
I was also curious if there is an easy spot to steal 24v to power a couple more relays. I was thinking I'd just tap off of the relay +. I'm using it to mute the cue signal when the tb is activated.

Re: Talkback Comp Build Thread

Posted: Tue Mar 01, 2022 10:54 am
by Joe Malone
williard86 wrote:
Tue Mar 01, 2022 10:48 am
Hi thanks I found a few.
I was also curious if there is an easy spot to steal 24v to power a couple more relays. I was thinking I'd just tap off of the relay +. I'm using it to mute the cue signal when the tb is activated.
Any relays need to be connected across the +/-V rails and not connected to 0v. So if using +/-15v for example = 30v then add a resistor in series with the relay to keep 24v across the relay. Do this external to the talkback comp directly across the power rails going to the talkback comp pcb.

SInce you will probably want to operate both relays at the same time then yes you could wire across the relay on the pcb with the same type relay and change R28 from 1k2 to 600ohm

Re: Talkback Comp Build Thread

Posted: Wed Sep 14, 2022 3:46 am
by slb1959
mrclunk wrote:
Tue Dec 10, 2019 8:45 pm
I'm sorry Joe, i ment to update my post...
Mic worked fine using the standard (2 x 6k8) supply as on the pcb. It's an Astrada conference mic 952.353UK (just the gooseneck mic part)
All working nicely on our Calrec. I added a 1k Log pot across the output for volume and a cheap OEP a262a2e transformer to split the output.
One to the desk auxs and a separate out to patchbay for remote session down Skype etc.
Hi. Can you make a simple draw of that. I have the same OEP in the drawer, and i need a volume pot too. Thanks in advance.