GroupDIY

Project Specific Discussions => Dynamic Processors => Topic started by: weiss on April 10, 2019, 01:29:52 PM

Title: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: weiss on April 10, 2019, 01:29:52 PM
I have a TwinQ channel strip from a friend where the right channel shows weird behaviour in the signal pathway. The signal has interruptions and when that happens the meter moves nervously up and down. But as far as i can tell  the preamp does seems fine because there the meter shows no unsteady movement.  I uploaded a sound sample to make things clearer.
It sounds like a helicopter noise..

I have some pictures here but i guess the sound sample will tell more..

(https://i.ibb.co/q79BjD4/1.jpg) (https://ibb.co/q79BjD4) (https://i.ibb.co/PFcnMnn/2.jpg) (https://ibb.co/PFcnMnn) (https://i.ibb.co/HDF1Db2/3.jpg) (https://ibb.co/HDF1Db2)

Title: Re: JoeMeek TwinQ signal interruption problem (right channel)
Post by: weiss on April 10, 2019, 01:45:40 PM
here are the sound samples (rename .txt to .zip and then unzip)
Title: Re: JoeMeek TwinQ signal interruption problem (right channel)
Post by: scott2000 on April 10, 2019, 03:35:26 PM
That's pretty weird.....

(https://media.giphy.com/media/RMMlJyi2Dfqi4/giphy.gif)


I saw there's a schem for the old Twin Qcs floating around....Pretty sure they're different though.....

Title: Re: JoeMeek TwinQ signal interruption problem (right channel)
Post by: weiss on April 10, 2019, 05:50:45 PM
That's pretty weird.....

(https://media.giphy.com/media/RMMlJyi2Dfqi4/giphy.gif)


I saw there's a schem for the old Twin Qcs floating around....Pretty sure they're different though.....
yeah, i'm clueless...
could it be the optical component? or the transformer?
Does anyone have a schematic ??
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: weiss on April 13, 2019, 05:54:08 AM
no one?  :-\
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: fripholm on April 26, 2019, 03:38:01 PM
To me it sounds like an extremely fast release time. Maybe one of the timing caps (most Joemeek comps have more than one) has gone bad or something in the sidechain/timing circuit?
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: weiss on April 26, 2019, 06:52:19 PM
To me it sounds like an extremely fast release time. Maybe one of the timing caps (most Joemeek comps have more than one) has gone bad or something in the sidechain/timing circuit?

Hey!
Thanks for the input. But wouldn’t it just distort then? It is alternating, that‘s What irritates me...  :o
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: fripholm on April 27, 2019, 03:10:22 AM
LDRs have their own inherent timing 'built in' as well. How fast depends on the model used. Maybe that's why it doesn't get fast enough for just distortion.

Does this 'helicopter effect' change when you turn the release knob?
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: weiss on April 27, 2019, 01:13:35 PM
LDRs have their own inherent timing 'built in' as well. How fast depends on the model used. Maybe that's why it doesn't get fast enough for just distortion.

Does this 'helicopter effect' change when you turn the release knob?

oh wow. you are right!
i turned the knob and the effect stopped. i'm gonna watch this and see if it stopped for good or if it returns, if it would come back, do you happen to know which capacitor could be defective?

thank you very much already !!  :D
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: fripholm on April 28, 2019, 06:30:05 AM
This doesn't necessarily mean that something is defective. Light dependent resistors are all over the place with their resistance and/or timing values - even with the same model (from the photo it looks like a Silonex NSL32). Maybe that's the reason why it happens on only one channel using the same settings.

I once had a Joemeek ThreeQ mic pre. While the preamp and the EQ were useable, the opto compressor in this thing sounded horrible.  It was able to punch holes in the audio signal every time a transient came along.  This happened in a very unpredictable manner and didn't sound musical at all - regardless of the settings used...
Title: Re: JoeMeek TwinQ signal interruption problem (helicopter noise)
Post by: weiss on April 28, 2019, 10:07:58 AM
This doesn't necessarily mean that something is defective. Light dependent resistors are all over the place with their resistance and/or timing values - even with the same model (from the photo it looks like a Silonex NSL32). Maybe that's the reason why it happens on only one channel using the same settings.

I once had a Joemeek ThreeQ mic pre. While the preamp and the EQ were useable, the opto compressor in this thing sounded horrible.  It was able to punch holes in the audio signal every time a transient came along.  This happened in a very unpredictable manner and didn't sound musical at all - regardless of the settings used...

alright, thank you!  :)
yeah i know, i wouldn't use this in my studio. It is not my own compressor, a friend gave it to me  ::)