Psionics NG4 Quad Noise Gate

[felix1988]

hi everybody!

this is my first post so i hope this is the right section

i found this unit in a very small local club i sometimes do live sound in. theres no outboard there besides a samson quadgate/compressor unit so i hoped i would get this one running. unfortunately i couldn't find any information online so you guys are my last hope

the unit powers up and the led indicators work and seem to make sense - i fed a recorded snaredrum into the channels one by one out of the output of my interface. the led turned green and red just as if the gate was working. also the attack and release settings seemed correct (as far as i could tell from the lights).
unfortunately there was no output on any of the channels.

does anybody have a guess what the reason could be or what i should check? i thought about changing the ics but isn't it weird that there is no output on all the channels? with no output i mean silence by the way

my understanding of circuits is pretty limited and so far i only build a few CAPI and Soundskulptor 500 kits so i don't quite know what i should do to troubleshoot.

any help would be appreciated

thanks!
felix

 

[PRR]

"The Psionics NG4 quad noise gate has four channels each with gain, threshold, attack, release and depth (range) adjustable controls, provision for mic inputs with 30 dB gain boost, provision for external keying, LED indication of gating and a bypass switch. All four channels are in standard 19 in 1 U rack and it represents one of the best examples of compressing large numbers of controls into a small area, while still retaining clarity, that I have seen. "
STUDIO SOUND, MARCH 1984

 

[analogguru]

The Psionics NG4 has a balanced "Mic/Line In" which is also active in the bypass mode.  Even the "Key In" is balanced.

BUT the output is unbalanced - with the "old norm" from the 80´s, which means on the XLR-jack: pin 1 is ground, pin 2 is ground (cold) and pin 3 is "HOT", the signal.  I would suggest that you verify your wiring for this.  Wrong cables - no signal.

There is also a "Mono Sum Output" XLR-jack where all 4 channels appear mixed together.  Same connection as above.

 

[felix1988]

The Psionics NG4 has a balanced "Mic/Line In" which is also active in the bypass mode.  Even the "Key In" is balanced.

BUT the output is unbalanced - with the "old norm" from the 80´s, which means on the XLR-jack: pin 1 is ground, pin 2 is ground (cold) and pin 3 is "HOT", the signal.  I would suggest that you verify your wiring for this.  Wrong cables - no signal.

There is also a "Mono Sum Output" XLR-jack where all 4 channels appear mixed together.  Same connection as above.

ah didn't know that! will try asap!
thank you!!

 

[felix1988]

update:

i tried it with the xlr to mono jack cable there was still no output when i used the line ins of my interface. then i tried the front input of the interface which is also a preamp and cranked the gain i could hear the signal then but super quiet. it might have been lacking bass compared to the dry signal but hard to tell because it was so quiet. the gating seemed to work as intended. when i cranked the gain on the noisegate i could hear the signal beeing distorted but the level did not change.
the behavior was the same for the normal output as well as for the summed output.

does this ring any bells? what could be the problem?
the threshold was at what i  think would be a normal level (around -5 to 0 dB, signal was a pretty heavily processed snaresample) so i think theres something wrong in the output stage. should i try to change the tl072cp ics?
or is it something different? still its kinda weird because its the same on all channels.

Thanks!

 

[analogguru]

update:

i tried it with the xlr to mono jack cable there was still no output when i used the line ins of my interface.

A standard, "modern" XLR-to-jack cable won´t deliver you any results.  As I wrote before:

The "modern" cable uses pin 2 of the XLR for the signal while on the Psioncs NG 4 pin 2 is grounded.
The "modern" cable has pin 3 connected to ground while on the Psionics NG 4 on pin 3 is the signal.

So you need a cable where pin 3 of the XLR is connected to the tip of the jack, while pin 1 of the XLR is connected to the sleeve of the jack.  You can leave pin 2 of the XLR open or connect it to ground.

 

[felix1988]

update:

i tried it with the xlr to mono jack cable there was still no output when i used the line ins of my interface.

A standard, "modern" XLR-to-jack cable won´t deliver you any results.  As I wrote before:

The "modern" cable uses pin 2 of the XLR for the signal while on the Psioncs NG 4 pin 2 is grounded.
The "modern" cable has pin 3 connected to ground while on the Psionics NG 4 on pin 3 is the signal.

So you need a cable where pin 3 of the XLR is connected to the tip of the jack, while pin 1 of the XLR is connected to the sleeve of the jack.  You can leave pin 2 of the XLR open or connect it to ground.

checked again and of course i had it wrong now everything works just fine!
thank you for your help and patience!

 

[analogguru]

....now everything works just fine!

Nice to hear that.

thank you for your help and patience!

You are welcome.