That2180 vca based compressor-90deg detector filter

[richiyobs]

Hi builders
In last period I read and compared a lot of schemos to understand how envelope detectors really work, cause my starting idea was to replicate a Dbx165A model, Dbx165A and Rms Detector, the one with StopLevel control
But to much extreme for my beginning level, lots of detectors!!!! and also had the bad idea to use the free control port for limiting…. Old story, game over

If I m driven in that correct way I can build one ….as I did for diode compressor ahahahah
thanks to these readings and the support and patience of great members I was able to apply
an old DBX patent…. Great Mr Blackmer!
My curiosity started cause reading pages and pages in this forum once discovered the term Hilbert Transform by Gyraf
I thought it could be a solution to sum 2 feedbacks at 1 side chain, so with one control boards adjust 2 channels…. To not match stuff and also avoid the central energy sum…. I was using it wrong! now I understand how to implement that Concept
Also saw similar patents for avionic radio transmissions… anyway here is my scheme using That2180 for VCA
RMS dtk is just an approximation of what could be a DBX one…. it worked! Id like to see an original scheme….hard to find
Spent lots of time trying to smooth its response playing with the timing cap in simulation , when understood its important role
For someone with good knowledge it s an easy task but for me was a funny and interesting adventure for learnig stuff
The controlAmp is from Thacorp design notes, attack and release a simple net buffered as Pico Comp, now i can add a meter driver for GR without altering compression
The 90degree Filter is the noted Studer one Studer 1 194 533. 90 degree shifter. LTspice file

here i posted the patents Studer 1 194 533. 90 degree shifter. LTspice file

thanx for your attention and for the support i got

Best
Richi

 

[Analog_Fan]

What does the parallel opamps do?
they use the same resistors but in opposite configuration, U7 and U8, can't zoom in to the image.
Than the big parallel circuit in front accept different resistors.
better inline the schematic and a bit bigger.

 

[richiyobs]

sorry i did a screenshot at full screen, have to organize it better
U7 and U8 is part of the rms detector and square in symmetry
attached a pdf

 

[Analog_Fan]

Thank you.

so the signal from the that 2180 enters the "phase shifter"? or rectifier? or both?

 

[richiyobs]

Thank you.

so the signal from the that 2180 enters the "phase shifter"? or rectifier? or both?

The signal comes from the input and goes to the sidechain... First the shifter then rectifier... Then to controlAmp and finally to the positive control port of 2180

Bes

 

[Analog_Fan]

i haven't experimented with phase shifters.

it's on the to do list.
Love to hear it when its done.

Check Befaco Slew limiter
https://www.befaco.org/slew-limiter/https://befaco.org/docs/Slew_Limiter/Slew_Limiter_V1_2_Schematic.pdf
So you can add a ATTACK and DECAY property to it and a Shape to the control voltage of the AR envelope, giving it logarithmic properties.
The transistor core is awesome.


You should check the Falstaff simulator, there is a better rectifier circuit as example.
You can see in real time what your circuit does, accept you have to use a LM13700, no THAT2180 model there.
mouse hover of a resistor and change the value by scrolling the wheel and see what happens in real time.

i have done the Moog filter in the Falstad simulator and it behaves like the real thing, the clone i have at house.
You can add as much oscilloscopes as you want, just right click a element.

 

[richiyobs]

i haven't experimented with phase shifters.

it's on the to do list.
Love to hear it when its done.

Check Befaco Slew limiter
https://www.befaco.org/slew-limiter/https://befaco.org/docs/Slew_Limiter/Slew_Limiter_V1_2_Schematic.pdf
So you can add a ATTACK and DECAY property to it and a Shape to the control voltage of the AR envelope, giving it logarithmic properties.
The transistor core is awesome.


You should check the Falstaff simulator, there is a better rectifier circuit as example.
You can see in real time what your circuit does, accept you have to use a LM13700, no THAT2180 model there.
mouse hover of a resistor and change the value by scrolling the wheel and see what happens in real time.

i have done the Moog filter in the Falstad simulator and it behaves like the real thing, the clone i have at house.
You can add as much oscilloscopes as you want, just right click a element.

Thanks i ll check!

 

[Analog_Fan]

You can push even audio through that "slew Limiter", not sure if this would be useful for normal audio in any sense.
unless you're going to work with tiny expensive precision capacitors and opamps to hear it.

Just build it in the Falstad simulator and see for your self.
But would probably be a very cool thing behind the rectifiers to control the That2180.
The slew limiter takes everything, just gotta make the voltage suitable for the That2180.

 

[Analog_Fan]

in FAQ i did build it.

Befaco Slew Limiter Falstad simulation:
https://tinyurl.com/23yezemu
Click the SPDT switch to make it work.

hover over the oscilloscope traces to see what "track" is lighting up.
the first scope is the output.

hover over the potentionmeter slider in the right column or right side, to see which pot in the circuit.
You can right click any track and see the voltage and amps over that track.

play with the SHAPE know and see the output change it's curve.
it's looks newby or amateur software, but you can make sub circuits, so you don't have to clutter the "worksheet" with wires and have a trazillion components.
it's just Paul hasn't grouped the input's and output's very wel to build such sub circuits, the are scattered over several grooups in the list, but it works.

to add new elements just right click in the work area.

 

[Analog_Fan]

here is with an audio input.
https://tinyurl.com/2yt4tcyq
just have to select a mp3 file on your "machine".

via the option "menu", "other options" you can adjust the speed of the simulator.
time step size: 1m = 1 millisecond, other wise your would wait an age for audio to show up.

 

[richiyobs]

here is with an audio input.
https://tinyurl.com/2yt4tcyq
just have to select a mp3 file on your "machine".

via the option "menu", "other options" you can adjust the speed of the simulator.
time step size: 1m = 1 millisecond, other wise your would wait an age for audio to show up.

HI Analog still have to check the simulator... As soon I can I ll try to run your links... Thanks, very interesting...
So is it possible to run audio file into simulator and listen to a processed one? Cool feature if it is so
Once I tried to use Qucs or something similar for this purpose... It s used by Plugin developers to import in python o similar all the data and of course in Real time it let s you process audio and create vst
Only limitation you get few component models... But it was years ago.... Have to check for new releases..

 

[richiyobs]

For the slew limiter... Took a quick look at the schemo
The shape control adjust the tracking mode, right? Linear or log....
In my idea used dbx approach to get antilog response... It s the way the human ear reacts to stimulus... That s what I could understand and tried to apply
If you also look the dbx118 schemo you ll find a compander Amp!
I m trying to have 2 control amps summed at Cv on simulation.... But first wanna build a proto to check it
Best

 

[richiyobs]

Check Befaco Slew limiter
https://www.befaco.org/slew-limiter/https://befaco.org/docs/Slew_Limiter/Slew_Limiter_V1_2_Schematic.pdf

https://www.haraldswerk.de/Utilities/Slew/Slew.html#Anker03is this the same concept?

best

 

[Script]

Is your schematics maybe missing diodes in the ATT and REL circuitry ?

 

[richiyobs]

Is your schematics maybe missing diodes in the ATT and REL circuitry ?

You re right... Removed cause they change the Cv slope in a bad manner.... I think it s working... I m not a Pro in simulation but looks doing something
Still looking for a better but simple config
Using it drawn in line instead of loop buffered works for sure... But this way can add a meter driver without altering compression
Have you got any suggestions?
Best

 

[richiyobs]

this seems a good way....

Edit- also attached another possible one, believe it s a right one, Thatcorp has bjt array, no way for me

 

[richiyobs]

sorry had attached a wrong screenshot
should this work? saw this config in RM57
simple charging and discharging C5... right?

Thanx for attention

 

[Analog_Fan]

HI Analog still have to check the simulator... As soon I can I ll try to run your links... Thanks, very interesting...
So is it possible to run audio file into simulator and listen to a processed one? Cool feature if it is so
Once I tried to use Qucs or something similar for this purpose... It s used by Plugin developers to import in python o similar all the data and of course in Real time it let s you process audio and create vst
Only limitation you get few component models... But it was years ago.... Have to check for new releases..

it has an audio output pin, but it doesn't work on my system so i can't tell you, but it appears on the scope.
tried QUCS aswel but couldn't get it runningm, seams to be an abandoned project or so when i checked.

The audio input is like a pin in the circuit, if you use it you can select a mp3 file.

 

[Analog_Fan]

https://www.haraldswerk.de/Utilities/Slew/Slew.html#Anker03is this the same concept?

best

the concept is the same, but the Befaco module circuit is much more "advanced".
the shape control is a pot instead of a SPDT switch.

 

[Analog_Fan]

this seems a good way....

Edit- also attached another possible one, believe it s a right one, Thatcorp has bjt array, no way for me

what is the file from the That cooperation?
to have a look at this circuit.