In design notes... Check diy pedal
That2180 vca based compressor-90deg detector filter
- Thread starter richiyobs
- Start date
Help Support GroupDIY Audio Forum:
Here's a thread from a guy named puretube who did an envelope circuit using a "90-degree", aka dome filter
https://www.diystompboxes.com/smfforum/index.php?topic=25313.0to reduce ripple.
Might be what riciyobs is looking for, or at least a lead FWIW
https://www.diystompboxes.com/smfforum/index.php?topic=25313.0to reduce ripple.
Might be what riciyobs is looking for, or at least a lead FWIW
Thanks for the link... Yes the quadrature reduced ripples... Everything from rectifier to Cv out smoothed... This technique gives an analytic extraction of the envelope as declared
Believe also distortion at low freq
Best
- Joined
- Jul 8, 2010
- Messages
- 513
You might want to look at the Weaver Alignment for the Dome filter. It has less ripple than the Studer.
https://proaudiodesignforum.com/forum/php/viewtopic.php?p=16533#p16533
R. B. Dome was the name of the "inventor": The Studer "90° Filter" Stereo to Mono Summer/Recorrelator - Pro Audio Design Forum
https://proaudiodesignforum.com/forum/php/viewtopic.php?p=16533#p16533
R. B. Dome was the name of the "inventor": The Studer "90° Filter" Stereo to Mono Summer/Recorrelator - Pro Audio Design Forum
Fine! Thank you so much... I ll experiment
Analog_Fan
Well-known member
did ya check the Befaco slew limiter simulation?
it follows the input voltage rather than a traditional ADSR or AR envelop that outputs 10 volts from a syntesizer, it does no rise above the input voltage, but you control the rise and fall.
Yes a quick check... But in few time I couldn t understand... Have to find time... I m reorganizing all my Sim to avoid errors... As I can I ll retry
But can you please better explain the advantages respect to a standard config?
Best
Analog_Fan
Well-known member
wel, therefor you need check the "befaco Slewlimiter" simulation i gave you.
play an hour or so with it.
you can adjust the input voltage before the switch, to see what i mean, that it follows the input voltage.
Use the scroll wheel of the mouse to adjust resistors, capacitors.
it's very a cool circuit, based on the DUSG (Universal Slope generator) circuit from Serge, witch it's used the company "Make Noise" as Make Noise "math's".
the world most sold "eurorack" synthesizer module. i got serial 9000+.
the dual long tail transistor amplifier, although in this case horizontal is the magic.
It's a pretty difficult circuit in the original form, but Befaco Changed it, they are Spanish.
another advanced it the "shape", instead of linear "effect", you can give it a logarithmic shape (the shape "slider" in the right column.
Spice is specialist simulator, Falstad is a constant real time simulator, good enough for fast "bread boarding".
You can save your work to disc or save the URL, share URL with other people.
Check the "app's" on the website of Paul Falstad, he has more pure math application on there.
Spice is good for circuits like Equalizers, (active filtes), etc, although the same can be done with the Falstad simulator as long as you know how to use it.
The scope settings can be accessed by right clicking the icon in the particular scope and options menu.
Spice is like a one shot simulator, while the Falstad allows you to play with the "interface" of the device you're building and see how it works in real time.
Try build the device you're making in the falstad simulator to see if it behaves like you expect, before you start soldering and finding out it doesn't.
But you have to use LM13700 instead.
save it, than build in the "befaco slew limiter" on the right spot.
Both are very good, but both can do task differently.
play an hour or so with it.
you can adjust the input voltage before the switch, to see what i mean, that it follows the input voltage.
Use the scroll wheel of the mouse to adjust resistors, capacitors.
it's very a cool circuit, based on the DUSG (Universal Slope generator) circuit from Serge, witch it's used the company "Make Noise" as Make Noise "math's".
the world most sold "eurorack" synthesizer module. i got serial 9000+.
the dual long tail transistor amplifier, although in this case horizontal is the magic.
It's a pretty difficult circuit in the original form, but Befaco Changed it, they are Spanish.
another advanced it the "shape", instead of linear "effect", you can give it a logarithmic shape (the shape "slider" in the right column.
Spice is specialist simulator, Falstad is a constant real time simulator, good enough for fast "bread boarding".
You can save your work to disc or save the URL, share URL with other people.
Check the "app's" on the website of Paul Falstad, he has more pure math application on there.
Spice is good for circuits like Equalizers, (active filtes), etc, although the same can be done with the Falstad simulator as long as you know how to use it.
The scope settings can be accessed by right clicking the icon in the particular scope and options menu.
Spice is like a one shot simulator, while the Falstad allows you to play with the "interface" of the device you're building and see how it works in real time.
Try build the device you're making in the falstad simulator to see if it behaves like you expect, before you start soldering and finding out it doesn't.
But you have to use LM13700 instead.
save it, than build in the "befaco slew limiter" on the right spot.
Both are very good, but both can do task differently.
Analog_Fan
Well-known member
https://www.falstad.com/circuit/circuitjs.html
the default starting circuit is like a RC, LC circuit, not sure with a voltage source.
But it has some cool motion to it and takes a while before it ends.
Than explore the Example circuit in the "help" menu, they are neat and mostly better than the things you find online.
the default starting circuit is like a RC, LC circuit, not sure with a voltage source.
But it has some cool motion to it and takes a while before it ends.
Than explore the Example circuit in the "help" menu, they are neat and mostly better than the things you find online.
Analog_Fan
Well-known member
Falstad is for the bright idea you cooked right now.
You can build logic circuits in there and see how it behaves in realtime, like they do in Cd4000, 74HC series.
Spice it to fine tune, to make sure you got the right capacitors, inductors and making sure it behave stable at any time, since falstad uses math perfect capacitors, inductors, default things.
You can build logic circuits in there and see how it behaves in realtime, like they do in Cd4000, 74HC series.
Spice it to fine tune, to make sure you got the right capacitors, inductors and making sure it behave stable at any time, since falstad uses math perfect capacitors, inductors, default things.
Analog_Fan
Well-known member
this one:.
https://tinyurl.com/2yt4tcyq
the one with the audio input.
right click the audio input above the switch on the left in the circuit, select a mp3 on your computer, adjust the "time step" settings to 1m, to set 1 millisecond, otherwise you will grow a beard first before you see the start of the song.
and see the "envelop" ride over the audio by playing the "rise" and "fall" or attack and decay slider in the right column.
You can also see how the "peak" detector from your circuit works in real time, but rather the ATTACK/decay circuit in your circuit, use the fbefaco slew limiter instead. just build it in front of it and move the audio input. and falstad has a better wave rectifier circuit in the examples circuits.
https://tinyurl.com/2yt4tcyq
the one with the audio input.
right click the audio input above the switch on the left in the circuit, select a mp3 on your computer, adjust the "time step" settings to 1m, to set 1 millisecond, otherwise you will grow a beard first before you see the start of the song.
and see the "envelop" ride over the audio by playing the "rise" and "fall" or attack and decay slider in the right column.
You can also see how the "peak" detector from your circuit works in real time, but rather the ATTACK/decay circuit in your circuit, use the fbefaco slew limiter instead. just build it in front of it and move the audio input. and falstad has a better wave rectifier circuit in the examples circuits.
Last edited:
HI Analog thanks for your great explanation! For sure I ll check it better... It s a cool feature seeing in real time how circuit works... Very helpful for a newbie like me... It took me lots of time make Lt works... So I m a bit scared starting a new simulator... But It s an interesting way to run...
So your advice is to put the Befaco slew limiter in front of the detector... Right?
Let s see... I ll keep you updated
Best
ran Falstad... starting to understand a bit.....
is there a way to listen to the processing sound?
so according to befaco s schemo the input buffer defines the shape of the detector made by the bjt array...right?
is c4 Timing cap? or both c3 and c4 for charge and discharge?
rise and fall cv out are used to drive external devices?
edit- or rise and fall cv are for external sidechain?
thanks for attention
best
Last edited:
Analog_Fan
Well-known member
nope,
Fine tune your peak detector in the Falstad simulator.
just extract it from your circuit,start with the Falstad wave rectifier in the example list from the "help menu", that one is better than yours, drag with your mouse over the entire circuit to select it and use "control + C & Control & V" to copy and paste in a new circuit or just build your peak detector behind it and see how it works.
right click the work area and search for the audio input in the component list.
the analog output is the first element in the "output and Labels" section.
the audio input in the "input section" 3rd from below.
the befaco slew limiter comes behind the peak detector and the wave rectifier.
the goal of the peak detector is to act on on a set amplitude, the threshold and make the That2180 close or reduce the volume, compress.
the Befaco slew limiter gives it character. like a delay witch is a desired effect and professional compressor can do.
the peak detector is the heart of the circuit and deserves a lot of thought.
Analog_Fan
Well-known member
Yep, C4 is the timing cap.
that's the you might want to adjust in the real circuit to a smaller one, like 1nF or so.
Use Wima AC pulse capacitors or some other high spec with a 2.5% tolerance.
2nF2
https://eu.mouser.com/ProductDetail/WIMA/FKP2C012201D00HSSD?qs=WI052HLiD5jLQ3B/QKmOLQ==size:
| 7.2 mm (length) | 4.5 mm (width) | 6 mm (height) | ||
| brand: Wima (Germany) | ||||
| Series: FKP 2 | ||||
| Tolerance: 2.5% | ||||
|
https://eu.mouser.com/ProductDetail/WIMA/FKP2C011001D00HSSD?qs=WI052HLiD5hOMKujMbXT9w==1nF
C3 is to make the circuit stable, use this one
100pF
https://eu.mouser.com/ProductDetail/WIMA/FKP2C001001D00HN00?qs=WI052HLiD5hqsCUy38Lkcw==Film Capacitors
pretty much the best.
| 7.2 mm (length) | 4.5 mm (width) | 6 mm (height) | |||
| brand: Wima | |||||
| Series: FKP 2 | |||||
| Tolerance: 2.5% | |||||
|
pick a PCB footprint that you especially made for easy removal or unsoldering, a special made one with bigger holes so you don't overheat the small via and they come off the PCB and your project is destroyed, like 1.0 mm drill and 2 mm outer diameter or more. best is to use slotted holes using the milling layer in eagle (a topic on it's own) or custom via in Kicad.
Rise and Fall CV are indeed for external gear, you can leave the out if you like, unless you change them to an audio input with wave rectifiers.
Thanks for clarifying....
yes wima FKP .... using them on diodebridge and jfet comp-lim also
Will work on
Sure I ll trouble you again
Best
experimenting with a different detector...
builded a trident proto few time ago so tried to implement that approach, and it seems fine ... a phase splitter used as sort of window comparator
less components... also rised the range at dtk out so i believe to have 20dB of compression
attached fast ATT & slow REL
it s a lite schemo to fasten simulation
edit- the slope at dtk out makes harder compression
best
builded a trident proto few time ago so tried to implement that approach, and it seems fine ... a phase splitter used as sort of window comparator
less components... also rised the range at dtk out so i believe to have 20dB of compression
attached fast ATT & slow REL
it s a lite schemo to fasten simulation
edit- the slope at dtk out makes harder compression
best
Attachments
Last edited:
