Hello everyone !
I was looking for a simple audio compressor to pair with a microphone for live use, dedicated to the microphone. What do you think of this one? It has many interesting settings: input gain, ratio, threshold, make-up gain, THD set
I want to make pcb copies of this audio compressor. I tried to reproduced the schematic on EDA, this is the original link : Compresseur audio Sonelec 002 (for private use)
I have several routing attempts, I don't know which one is the best in the end because it's the first time I've tried this. I have a user constraint for the design of this PCB : place all the potentiometers on the front of the chassis, in direct soldering without additional wires. This is why I start with a PCB border of approximately 130x90mm. I only applied one beginner's rule... keep direct connections between components as close as possible.
what do you think about the schematics and routing suggestions of EDA ? I used automatic routing. With 2 layers there are 6 vias, with 4 layers there are 3 vias. No error messages, EDA indicates when the tracks are too close to each other...
Photo n°1: original schematic (x2 mono with link option). SW1 is a switch to connect two PCB together.
Photo n°2: my reproduction on EDA (x1 mono). what is not clear to me is : what happens to 18v and 18va written on the original diagram, at the time of automatic routing ? In my version, power is named "ALIM"! after routing (without error), the two tracks 18v and 18va of the original schematic disappear, can you explain to me why?
Photo n°3: 2-layers routing (ALIM = POWER !)
Photo n°4: 4 layers routing (ALIM = POWER!)
Photo n°5 : 4-layers routing n°2
I was looking for a simple audio compressor to pair with a microphone for live use, dedicated to the microphone. What do you think of this one? It has many interesting settings: input gain, ratio, threshold, make-up gain, THD set
I want to make pcb copies of this audio compressor. I tried to reproduced the schematic on EDA, this is the original link : Compresseur audio Sonelec 002 (for private use)
I have several routing attempts, I don't know which one is the best in the end because it's the first time I've tried this. I have a user constraint for the design of this PCB : place all the potentiometers on the front of the chassis, in direct soldering without additional wires. This is why I start with a PCB border of approximately 130x90mm. I only applied one beginner's rule... keep direct connections between components as close as possible.
what do you think about the schematics and routing suggestions of EDA ? I used automatic routing. With 2 layers there are 6 vias, with 4 layers there are 3 vias. No error messages, EDA indicates when the tracks are too close to each other...
Photo n°1: original schematic (x2 mono with link option). SW1 is a switch to connect two PCB together.
Photo n°2: my reproduction on EDA (x1 mono). what is not clear to me is : what happens to 18v and 18va written on the original diagram, at the time of automatic routing ? In my version, power is named "ALIM"! after routing (without error), the two tracks 18v and 18va of the original schematic disappear, can you explain to me why?
Photo n°3: 2-layers routing (ALIM = POWER !)
Photo n°4: 4 layers routing (ALIM = POWER!)
Photo n°5 : 4-layers routing n°2
I don't understand why your component placement is so spread out? That's could cause issues with too much stray capacitance - the layout should match the circuit diagram fairly closely (if the schematic is logically drawn!). Once components are in logical relation to each other many traces will be short and direct and routing is going to be more tight and could avoid problems related to spare/slack layout.
Not sure why the power rails have vanished, perhaps they are wrongly named (normally in many packages the supply trace name must match the component's power pin names).
Not sure why the power rails have vanished, perhaps they are wrongly named (normally in many packages the supply trace name must match the component's power pin names).
Autorouting for audio seldom works very well.
Just manually place the major parts, it's easier than making all the corrections.
Just manually place the major parts, it's easier than making all the corrections.
I think Rv101 is connected to the wrong side of the capacitor?
This design seems a bit complicated to me. Does it outperform the classic and much simpler JFET circuit? And I wonder if the chip availability is solid.
Also, the chip is two channels, and you are not making a stereo device, ie you are using just half the chip?
This design seems a bit complicated to me. Does it outperform the classic and much simpler JFET circuit? And I wonder if the chip availability is solid.
Also, the chip is two channels, and you are not making a stereo device, ie you are using just half the chip?
@steveu yes you can link them together with SW1 switch, or just use one channel (one circuit) without SW1. If you talk about C106 you was right that was my mistake, he was reversed, it was reversed, I corrected it. According to the designer, you can assemble only one channel. I chose the first one, in case I want to test a stereo version later.
@Mark Tillotson my components are so spread out because I don't know all the rules of good practice. I will try another layout in EDA following your remarks. In EDA I didn't know how to symbolize the 18v placed on the original diagram. So I took two +5v symbols that I renamed +18V-a and +18V. That was a good idea? I'll try other component layouts again, but I still have this preference to have pot in direct soldering, without wires, on the front.
@Mark Tillotson my components are so spread out because I don't know all the rules of good practice. I will try another layout in EDA following your remarks. In EDA I didn't know how to symbolize the 18v placed on the original diagram. So I took two +5v symbols that I renamed +18V-a and +18V. That was a good idea? I'll try other component layouts again, but I still have this preference to have pot in direct soldering, without wires, on the front.
New layout... he could be a bit better with some mm replacement
but above all I integrated a dual-pot print name "DUAL" because they are 2x10K linear on the schematic, it said "mecanical link 2x10k lin"...
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Still very spread out but definitely better! Horizontal one side and vertical the other is a common pattern. Consider ground-planes on both sides, stitched together with vias. I reckon it can be done in 60% of the area without too much struggle.
Power and ground traces are usually done significantly wider than signal traces to reduce the (inductive) impedance of the supply.
Don't forget mounting holes on the back corners 🙂
Power and ground traces are usually done significantly wider than signal traces to reduce the (inductive) impedance of the supply.
Don't forget mounting holes on the back corners 🙂
I've found that a copper "pour", defined as a ground plane on one side or the other, can make it easier to do a PCB layout. Typically, grounds are everywhere.
The same thing can be done on the other side for Vcc. If dealing with two supplies -- Vcc and Vee -- I have defined two planes, whose placement facilitates routing. Power/ground connections to devices usually take precedence in my PCB designs so the other nets have to accommodate that.
Though, truth be told, these days 4-layer boards are so inexpensive I usually take that option. Those extra 2 layers really make a difference in terms of ease of layout. In my layouts the inner two layers usually serve to provide Vcc, Vee and Gnd -- but can be used for interconnects if the layout is better, compared to other options.
You do need more silk screen nomenclature to indicate important I/O and power/ground connections. It also can be helpful to add a version number, in case you find it necessary to do more than one design turn. Otherwise it could be difficult to find the right PCB if you need to build up another one. I assure you that it's likely your first PCB will have some problem(s) you will want to address -- so you will end up with some boards that you do NOT want to accidentally use.
Not certain about the circuit operation? Or perhaps the designer's calibration notes talk about measuring some internal circuit nodes? You need to add some test points for that. All this stuff is easy to add now and will make your life MUCH easier down the road.
Optimism regarding your design is natural but taking the time to include a few CYA features in your PCB layout can pay big dividends.
The same thing can be done on the other side for Vcc. If dealing with two supplies -- Vcc and Vee -- I have defined two planes, whose placement facilitates routing. Power/ground connections to devices usually take precedence in my PCB designs so the other nets have to accommodate that.
Though, truth be told, these days 4-layer boards are so inexpensive I usually take that option. Those extra 2 layers really make a difference in terms of ease of layout. In my layouts the inner two layers usually serve to provide Vcc, Vee and Gnd -- but can be used for interconnects if the layout is better, compared to other options.
You do need more silk screen nomenclature to indicate important I/O and power/ground connections. It also can be helpful to add a version number, in case you find it necessary to do more than one design turn. Otherwise it could be difficult to find the right PCB if you need to build up another one. I assure you that it's likely your first PCB will have some problem(s) you will want to address -- so you will end up with some boards that you do NOT want to accidentally use.
Not certain about the circuit operation? Or perhaps the designer's calibration notes talk about measuring some internal circuit nodes? You need to add some test points for that. All this stuff is easy to add now and will make your life MUCH easier down the road.
Optimism regarding your design is natural but taking the time to include a few CYA features in your PCB layout can pay big dividends.
Hello your PCB component placement and layout is not optimized for Audio circuits. I can provide assistance if you need support, First you need to provide your target enclosure, then PCB dimensions. Auto-routing of PCB for Audio will not provide good result. We can collaborate, I have experience in designing PCBs for audio circuits.