https://theultimatetone.com/ Mon, 11 May 2026 12:47:41 +0000 MyBB https://theultimatetone.com/Thread-Upgrading-Eagle-version Fri, 20 Aug 2021 15:04:39 +0000 K O'Connor]]> https://theultimatetone.com/Thread-Upgrading-Eagle-version
If you were lucky enough to buy Eagle back when you could actually buy it for a one-time outlay of $$, you may be in a good position to upgrade to a better version. You are given a "key" on a floppy or other means and this is your licence to use Eagle and must be loaded when you load Eagle.

When CADsoft was around, they had various version of Eagle available for download. Your licence would open them once they were on your computer - it's been ages since I did that, so I'm probably not describing it correctly - and for most of my Eagle experience I've been using 4.16r2. The computer that lived on began recently to randomly shut itself off. This was a nuisance until one time I had just saved my Eagle work and the computer went off. I restarted it but then could not reopen that file - it was corrupted - lots of hours of work gone in a flash (more of a black-out).

Fortunately, I have another computer that a friend built for me and had loaded three Eagle versions onto: 6.3, 7.7 and 8.2. Also fortunate that the first computer behaved itself long enough for me to load my Eagle files and some other things onto a key so I could transfer them to the second computer. I placed the files into 6.3 and 7.7, both of which I had used minimally  in the past. I figured I would use 7.7 to rebuild the lost design.

The lost design was a rework of a previous design, so I began with that file. The board for this project is actually a panel of six boards and they happened to be positioned all around the origin instead of all in the upper right quadrant. This allowed me to place things accurately on the specific board I was working on, which was referenced to the origin. I tried to move  component but was blocked and a "board limit" window popped up. It turned out the 7.7 version was a crippled form, but my friend who loaded it would not have known that. Fortunately, the 6.3 was not crippled, so I am using it now.

The first computer with version-4 on it had a fatal flaw and is scrapped. The newer computer is faster and quieter - it is the quietest computer that has a fan that I've ever heard. It was designed specifically to be quiet so it could be in a living space. Frankly, having two potential work stations did not work for me; my brain can barely keep track of one computer, so the new paradigm is like the way-back paradigm and it's much easier. When my friend built this computer he had my Eagle key to be able to load the different versions. I believe 6.6 is still available on the web.

Like every Eagle version, 6.3 has its quirks. I believe they were trying to integrate Eagle with spice and 3D softwares, so some of the menus and file management is oriented towards that. For example, in older Eagle a project simply was saved directly into the Project folder. In 6.3, there are two subfolders in Projects, Eagle and Examples. Your projects go into the Eagle folder BUT not directly. Maybe there is a bug? but when you go to "ave" or "save as..." the Project folder only shows the Examples subfolder, so you have to save your project into there, then open both subfolders and rag and drop the project into Eagle.

Another quirk of 6.3 is that when you select the "Change" tool, the menu that appears has six completely useless-to-me options listed above "Layer", which used to be the top choice.

Another quirk is when you use the Group function. Old Eagle drew a box around the grouped elements, where 6.3 makes a shaded box. You used to be able to select the next function, say Move, then right click anywhere in the box to move the group. Then right click again to make a smaller move adjustment. In 6.3, when you right-click on the group a menu pops up of things you can do with the group. Move is way down on the list, so you cursor down and click and the the group has jumped down to your cursor. if you need to make a fine adjustment to the move, you have to right-click, cursor, have the group jump again and try positioning it more accurately. between these moves, it is best to change the scale so the adjustment can be made more precisely. of course, once the group is tied to the cursor the first time, you could cursor up to the Zoom-in function and try to move the group in one go.

A problem with group moves is that the cursor may not be in a convenient place within the group to accurately place the group where you want it. At least in old Eagle the group did not bounce around with each new attempt to move it.  You could make the first move and drop the group. Then zoom in and grab the group by the corner and move that corner to exactly where you want it.

Eagle is always throwing you little curves ]]>
If you were lucky enough to buy Eagle back when you could actually buy it for a one-time outlay of $$, you may be in a good position to upgrade to a better version. You are given a "key" on a floppy or other means and this is your licence to use Eagle and must be loaded when you load Eagle.

When CADsoft was around, they had various version of Eagle available for download. Your licence would open them once they were on your computer - it's been ages since I did that, so I'm probably not describing it correctly - and for most of my Eagle experience I've been using 4.16r2. The computer that lived on began recently to randomly shut itself off. This was a nuisance until one time I had just saved my Eagle work and the computer went off. I restarted it but then could not reopen that file - it was corrupted - lots of hours of work gone in a flash (more of a black-out).

Fortunately, I have another computer that a friend built for me and had loaded three Eagle versions onto: 6.3, 7.7 and 8.2. Also fortunate that the first computer behaved itself long enough for me to load my Eagle files and some other things onto a key so I could transfer them to the second computer. I placed the files into 6.3 and 7.7, both of which I had used minimally  in the past. I figured I would use 7.7 to rebuild the lost design.

The lost design was a rework of a previous design, so I began with that file. The board for this project is actually a panel of six boards and they happened to be positioned all around the origin instead of all in the upper right quadrant. This allowed me to place things accurately on the specific board I was working on, which was referenced to the origin. I tried to move  component but was blocked and a "board limit" window popped up. It turned out the 7.7 version was a crippled form, but my friend who loaded it would not have known that. Fortunately, the 6.3 was not crippled, so I am using it now.

The first computer with version-4 on it had a fatal flaw and is scrapped. The newer computer is faster and quieter - it is the quietest computer that has a fan that I've ever heard. It was designed specifically to be quiet so it could be in a living space. Frankly, having two potential work stations did not work for me; my brain can barely keep track of one computer, so the new paradigm is like the way-back paradigm and it's much easier. When my friend built this computer he had my Eagle key to be able to load the different versions. I believe 6.6 is still available on the web.

Like every Eagle version, 6.3 has its quirks. I believe they were trying to integrate Eagle with spice and 3D softwares, so some of the menus and file management is oriented towards that. For example, in older Eagle a project simply was saved directly into the Project folder. In 6.3, there are two subfolders in Projects, Eagle and Examples. Your projects go into the Eagle folder BUT not directly. Maybe there is a bug? but when you go to "ave" or "save as..." the Project folder only shows the Examples subfolder, so you have to save your project into there, then open both subfolders and rag and drop the project into Eagle.

Another quirk of 6.3 is that when you select the "Change" tool, the menu that appears has six completely useless-to-me options listed above "Layer", which used to be the top choice.

Another quirk is when you use the Group function. Old Eagle drew a box around the grouped elements, where 6.3 makes a shaded box. You used to be able to select the next function, say Move, then right click anywhere in the box to move the group. Then right click again to make a smaller move adjustment. In 6.3, when you right-click on the group a menu pops up of things you can do with the group. Move is way down on the list, so you cursor down and click and the the group has jumped down to your cursor. if you need to make a fine adjustment to the move, you have to right-click, cursor, have the group jump again and try positioning it more accurately. between these moves, it is best to change the scale so the adjustment can be made more precisely. of course, once the group is tied to the cursor the first time, you could cursor up to the Zoom-in function and try to move the group in one go.

A problem with group moves is that the cursor may not be in a convenient place within the group to accurately place the group where you want it. At least in old Eagle the group did not bounce around with each new attempt to move it.  You could make the first move and drop the group. Then zoom in and grab the group by the corner and move that corner to exactly where you want it.

Eagle is always throwing you little curves ]]> https://theultimatetone.com/Thread-Schematic-management Tue, 06 Aug 2019 22:50:25 +0000 K O'Connor]]> https://theultimatetone.com/Thread-Schematic-management
Part-1

When we draw a schematic by hand we are limited by the paper size as to how much circuitry we can comfortably fit onto the page. Symbols and text have to be large enough to read clearly, preferably without the need for a magnifying glass. Hand rendering usually invokes our sense of proportion and we try to keep similar symbols the same size as each other, and try to have room for what needs to be shown. We try to organise the circuit flow so it easy to follow and often use connection symbols such as GND and V+ to show things that are tied to each other without having to pull a line all the way across the page.

With computer software, and PCB design programs like Eagle, schematic entry is much the same as hand rendering except that we go to a library within the program to find symbols, then 'drop' them in place. Then we connect them with 'nets'. As we add more components we run out of space as far as the scale of our view goes, because Eagle defaults to a certain effective page size. We can zoom out and add more parts then use the 'fit' function to resize the circuit to the screen size. Things are smaller now, but likely with modern monitor sizes we can still read component names and values. However, it is very easy to get to a point where you have to begin zooming in to read text, and that becomes a problem if you ever want to print out the schematic.

In drafting, there are standard size "sheets", or paper sizes. 'A' is the same size as a North American letter size, 8.5" x 11". The orientation can be long-side vertical (portrait) or long-side horizontal (landscape). Size 'B' is twice the area; 'C' is four times; 'D' is eight times and 'E' is sixteen times. Obviously, for hobbyists and home users, printing anything other than 'A' size is impossible  Yes, there is 'legal' size paper and in Europe size A4 is slightly larger than letter size.

Eagle provides a facility to have multiple sheets for the schematic. This allows you to break the circuit into smaller portions that can be printed more easily and more legibly. When we need to make a connection tie from one sheet to another, we use "ports" or "wire links". These are DEVICES in the Eagle library that let you have these page breaks yet on the board the same-labelled ports are tied together by a trace.]]>
Part-1

When we draw a schematic by hand we are limited by the paper size as to how much circuitry we can comfortably fit onto the page. Symbols and text have to be large enough to read clearly, preferably without the need for a magnifying glass. Hand rendering usually invokes our sense of proportion and we try to keep similar symbols the same size as each other, and try to have room for what needs to be shown. We try to organise the circuit flow so it easy to follow and often use connection symbols such as GND and V+ to show things that are tied to each other without having to pull a line all the way across the page.

With computer software, and PCB design programs like Eagle, schematic entry is much the same as hand rendering except that we go to a library within the program to find symbols, then 'drop' them in place. Then we connect them with 'nets'. As we add more components we run out of space as far as the scale of our view goes, because Eagle defaults to a certain effective page size. We can zoom out and add more parts then use the 'fit' function to resize the circuit to the screen size. Things are smaller now, but likely with modern monitor sizes we can still read component names and values. However, it is very easy to get to a point where you have to begin zooming in to read text, and that becomes a problem if you ever want to print out the schematic.

In drafting, there are standard size "sheets", or paper sizes. 'A' is the same size as a North American letter size, 8.5" x 11". The orientation can be long-side vertical (portrait) or long-side horizontal (landscape). Size 'B' is twice the area; 'C' is four times; 'D' is eight times and 'E' is sixteen times. Obviously, for hobbyists and home users, printing anything other than 'A' size is impossible  Yes, there is 'legal' size paper and in Europe size A4 is slightly larger than letter size.

Eagle provides a facility to have multiple sheets for the schematic. This allows you to break the circuit into smaller portions that can be printed more easily and more legibly. When we need to make a connection tie from one sheet to another, we use "ports" or "wire links". These are DEVICES in the Eagle library that let you have these page breaks yet on the board the same-labelled ports are tied together by a trace.]]> https://theultimatetone.com/Thread-Library-parts Sun, 23 Sep 2018 18:12:45 +0000 K O'Connor]]> https://theultimatetone.com/Thread-Library-parts
In Eagle and other PCB layout software, the components are stored in a parts "library". Eagle comes with some libraries developed over the years by its developers, and to which you can add your own parts. It is your choice whether to use the default libraries or to make your own for things that you use all the time, as this can save a lot of scrolling through the existing libraries.

Note that the libraries are listed alphabetically in the library directory. If you create your own directory it is convenient if it shows up at the top of the list. To force this, use numbers at least as the first part of the library name, or as the entire name. I use a couple of libraries named this way: one for laying out schematics, and another for laying out mechanical drawings for chassis and face plates.

Each component is called a DEVICE. A DEVICE is comprised of a SYMBOL that goes on the schematic and a PACKAGE that goes on the board. Each device can have s many packages as you wish, and some devices might actually require more than one symbol to be complete. For example, a resistor has only one functional element and thus has only one symbol, but because the resistor can be many different physical sizes, it can have many packages. A dual-triode, like a 12AX7, has three functional elements: two triodes and a heater. If the DUAL-TRIODE device is made correctly to assure proper schematic flow, the DEVICE will have three symbols and then one or more packages as required. Ideally, the 12AX7 should have two packages: one for mounting on the top side of the board and one for mounting on the bottom side. Alternatively, you can have one package and use the MIRROR tool once the package is placed on the board.

You can go in to the library directly, but it is usual to have a schematic open before invoking the Library directory.]]>
In Eagle and other PCB layout software, the components are stored in a parts "library". Eagle comes with some libraries developed over the years by its developers, and to which you can add your own parts. It is your choice whether to use the default libraries or to make your own for things that you use all the time, as this can save a lot of scrolling through the existing libraries.

Note that the libraries are listed alphabetically in the library directory. If you create your own directory it is convenient if it shows up at the top of the list. To force this, use numbers at least as the first part of the library name, or as the entire name. I use a couple of libraries named this way: one for laying out schematics, and another for laying out mechanical drawings for chassis and face plates.

Each component is called a DEVICE. A DEVICE is comprised of a SYMBOL that goes on the schematic and a PACKAGE that goes on the board. Each device can have s many packages as you wish, and some devices might actually require more than one symbol to be complete. For example, a resistor has only one functional element and thus has only one symbol, but because the resistor can be many different physical sizes, it can have many packages. A dual-triode, like a 12AX7, has three functional elements: two triodes and a heater. If the DUAL-TRIODE device is made correctly to assure proper schematic flow, the DEVICE will have three symbols and then one or more packages as required. Ideally, the 12AX7 should have two packages: one for mounting on the top side of the board and one for mounting on the bottom side. Alternatively, you can have one package and use the MIRROR tool once the package is placed on the board.

You can go in to the library directly, but it is usual to have a schematic open before invoking the Library directory.]]> https://theultimatetone.com/Thread-Incremental-vs-Complete-Schematic-Capture Sun, 23 Sep 2018 17:39:47 +0000 K O'Connor]]> https://theultimatetone.com/Thread-Incremental-vs-Complete-Schematic-Capture
Note that on the scale we are working on, ALL the work is by hand: hand stuffing of the PCB: hand soldering; hand assembly; hand wiring of whatever requires wiring; hand testing.

Suppose the project is a simple guitar amplifier.

If the amp is solid-state, then there are not too many thermal considerations other than where the output devices might be bolted to the chassis, or to a heatsink, and if the heatsinking will be adequate?

If the amp uses vacuum tubes, then we have to assure air flow around the tubes and try to keep their heat away from the PCB. Do we put the tubes on the PCB? Do we use chassis-mounted tube sockets and wire to the board from there? Let's suppose we decide to mount the tubes on the PCB. This has many advantages in that the wiring around the tube socket is "locked in" and parasitic capacitance will be controlled and will be consistent for every copy of this amplifier. Besides, card-mounted sockets eliminates nine connections per 12A_7 and up to six connections for each output tube. Suppose, then that the choice is to use PCB-mounting for the tubes.

In our vision of the amp, we know the general placement of the controls and tubes and jacks. In our modern time, the instinct would be to mount all of these items on one PCB to eliminate as much wiring as possible. Indeed, for a preamp-only or a power-amp-only this is easy to do and does not necessarily incur a weighty service penalty. For a complete amplifier it may be more problematic, so we might have to split the single large board into smaller pieces to make servicing easier.

Splitting the PCB into smaller parts also has the advantage of allowing a modular approach to the development of a product line - a "family" of amplifiers - and/or for easy construction of custom amps. It also allows one to use the less-expensive versions of Eagle or other PCB design software, where the board size is restricted.

Once we make these decisions regarding the board size and what is on it, we should first make a hand drawing with the dimensions for spacing of the externally visible and accessible components, then we can begin drawing the schematic. Because we have an idea of where some things should be placed on the PCB, we can choose to lay out the entire schematic THEN lay out the board, OR lay out a small part of the schematic and start the board, then add a few parts at a time, arranging them as we go along.

Using the entire schematic entry approach is the conventional design intent. You draw the schematic and then select the BOARD icon. Eagle asks "Create new board (named as your schematic)?". Press OK and the board editor opens with a rectangular board outline to the right and all the components arranged to the left. The parts have fly-wires between them showing what lead terminal ties to what other component terminal. It can be quite a mess and intimidating if the circuit is complex. The shapes of the components will make it obvious what each component type is, and they will be laid out in numerical order identical to the order they were dropped onto the schematic. This last detail explains why you might see R1, R2, etc at the middle or end of a schematic rather than at the beginning - the designer or draftsperson simply dropped R1 and used it in the first part of the circuit he/she was thinking about.

Note that (in older Eagle versions) the default board outline is on a 0.05" (50-mil) grid and represents the centre of the milling tool rather than the true board edge. Use the REMOVE tool to get rid of these lines, then use the DRAW tool to lay out a board outline closer to what it should really be. More on these specific actions later.

You should print out the schematic to assist with laying the board. In the board editor, you can use the MOVE command to move parts from the field onto the actual board. If you made that hand drawing of the key dimensions previously, now is when it comes in handy. You can draw reference lines on the board area to show how to precisely align and position the pots, jacks and tube sockets. Move these components first as their positions influence the positioning of all the small resistors and capacitors, and as to how to lay the traces between components.

Fortunately the MOVE feature allows you to enter the geographic designator or NAME of the component into the command line while the cursor is over the board area close to where the next part should be. Enter the name and that part is suddenly stuck to the cursor as a virtual component, ready to be dropped onto the board. left-click to drop the part, then enter the name of the next part to position. Use the ZOOM tools to better see the part of the board you are working on.

Alternatively, since you know the basic lay of the land for the board itself and likely have a schematic in mind, you might do the layout a bit at a time as you build up the schematic. Again, having the hand drawing with key dimensions for placement of the externally accessible parts is essential, although you can also make those decisions within Eagle. Suppose you open the schematic and drop the jacks and pots. Then open the board and make the proper outline for the board and add the reference lines for where the pots and jacks should go. Now move those parts from the field at left onto the board space, lining them up as they should be.

Here is where you can take advantage of the GRID command. Suppose all the pots and jacks are on a 1.5" spacing. Set the grid to 1.5" and for the grid lines to be visible. Now when you move a given component, it can only move in 1.5" increments and everything will be easily lined up to the required spacing. After these parts are in place, reset the GRID back to 0.1" or whatever small increment is appropriate. The dimensions here can just as easily be metric, with "easy" spacings based on millimetre or centimetre multiples. Using this technique might let you save the step of drawing the reference lines, but those are handy to have for other steps later, like laying out a chassis drawing.

Now you have the pots and jacks on the board where they should be and on the schematic in relative positions that may or may not promote a good schematic layout. Move them as required to make space for the next few components. Say we drop the tubes in next. 

Depending on how we have constructed our dual-triode symbol, we are either dropping individual triode sections OR dropping a dual-triode with each ADD command. Using the individually requested triode sections allows for an easier to follow schematic that does not have the signal doubling back on itself - the signal flows from left-to-right as it should. When we add the first triode section to the schematic, the entire dual-triode package is dropped into the unconnected component field in the board editor. The next triode section we drop onto the schematic does not change the board editor. The third triode section we drop adds a new duo-triode package to the board. Using the "component" dual-triode, the heater will be a third component that we drop onto the schematic later using the INVOKE tool. It takes two clicks to drop the two triodes onto the schematic, and a later step to connect the heaters, with the potential to forget about the heater wiring, but also for making a neater schematic.

If we have made the duo-triode symbol as exactly that - a dual triode with six connections - then each request for a dual-triode drops the two-section symbol on the schematic and the package onto the board. Most schematics using this symbol approach also have the heater connections within the symbol, so in fact there are nine-connection points made to the single schematic symbol. Where this is a more realistic presentation of the PHYSICAL component, it is NOT really what we want to have on the schematic. The schematic is an abstract representation of the circuit and should make following the signal and power flow EASIER than it is in the real world construction. Having this all-in-one symbol is intuitive but obfuscating at the same time. It allows each 12A_7 to be dropped onto the schematic and board in one click.]]>
Note that on the scale we are working on, ALL the work is by hand: hand stuffing of the PCB: hand soldering; hand assembly; hand wiring of whatever requires wiring; hand testing.

Suppose the project is a simple guitar amplifier.

If the amp is solid-state, then there are not too many thermal considerations other than where the output devices might be bolted to the chassis, or to a heatsink, and if the heatsinking will be adequate?

If the amp uses vacuum tubes, then we have to assure air flow around the tubes and try to keep their heat away from the PCB. Do we put the tubes on the PCB? Do we use chassis-mounted tube sockets and wire to the board from there? Let's suppose we decide to mount the tubes on the PCB. This has many advantages in that the wiring around the tube socket is "locked in" and parasitic capacitance will be controlled and will be consistent for every copy of this amplifier. Besides, card-mounted sockets eliminates nine connections per 12A_7 and up to six connections for each output tube. Suppose, then that the choice is to use PCB-mounting for the tubes.

In our vision of the amp, we know the general placement of the controls and tubes and jacks. In our modern time, the instinct would be to mount all of these items on one PCB to eliminate as much wiring as possible. Indeed, for a preamp-only or a power-amp-only this is easy to do and does not necessarily incur a weighty service penalty. For a complete amplifier it may be more problematic, so we might have to split the single large board into smaller pieces to make servicing easier.

Splitting the PCB into smaller parts also has the advantage of allowing a modular approach to the development of a product line - a "family" of amplifiers - and/or for easy construction of custom amps. It also allows one to use the less-expensive versions of Eagle or other PCB design software, where the board size is restricted.

Once we make these decisions regarding the board size and what is on it, we should first make a hand drawing with the dimensions for spacing of the externally visible and accessible components, then we can begin drawing the schematic. Because we have an idea of where some things should be placed on the PCB, we can choose to lay out the entire schematic THEN lay out the board, OR lay out a small part of the schematic and start the board, then add a few parts at a time, arranging them as we go along.

Using the entire schematic entry approach is the conventional design intent. You draw the schematic and then select the BOARD icon. Eagle asks "Create new board (named as your schematic)?". Press OK and the board editor opens with a rectangular board outline to the right and all the components arranged to the left. The parts have fly-wires between them showing what lead terminal ties to what other component terminal. It can be quite a mess and intimidating if the circuit is complex. The shapes of the components will make it obvious what each component type is, and they will be laid out in numerical order identical to the order they were dropped onto the schematic. This last detail explains why you might see R1, R2, etc at the middle or end of a schematic rather than at the beginning - the designer or draftsperson simply dropped R1 and used it in the first part of the circuit he/she was thinking about.

Note that (in older Eagle versions) the default board outline is on a 0.05" (50-mil) grid and represents the centre of the milling tool rather than the true board edge. Use the REMOVE tool to get rid of these lines, then use the DRAW tool to lay out a board outline closer to what it should really be. More on these specific actions later.

You should print out the schematic to assist with laying the board. In the board editor, you can use the MOVE command to move parts from the field onto the actual board. If you made that hand drawing of the key dimensions previously, now is when it comes in handy. You can draw reference lines on the board area to show how to precisely align and position the pots, jacks and tube sockets. Move these components first as their positions influence the positioning of all the small resistors and capacitors, and as to how to lay the traces between components.

Fortunately the MOVE feature allows you to enter the geographic designator or NAME of the component into the command line while the cursor is over the board area close to where the next part should be. Enter the name and that part is suddenly stuck to the cursor as a virtual component, ready to be dropped onto the board. left-click to drop the part, then enter the name of the next part to position. Use the ZOOM tools to better see the part of the board you are working on.

Alternatively, since you know the basic lay of the land for the board itself and likely have a schematic in mind, you might do the layout a bit at a time as you build up the schematic. Again, having the hand drawing with key dimensions for placement of the externally accessible parts is essential, although you can also make those decisions within Eagle. Suppose you open the schematic and drop the jacks and pots. Then open the board and make the proper outline for the board and add the reference lines for where the pots and jacks should go. Now move those parts from the field at left onto the board space, lining them up as they should be.

Here is where you can take advantage of the GRID command. Suppose all the pots and jacks are on a 1.5" spacing. Set the grid to 1.5" and for the grid lines to be visible. Now when you move a given component, it can only move in 1.5" increments and everything will be easily lined up to the required spacing. After these parts are in place, reset the GRID back to 0.1" or whatever small increment is appropriate. The dimensions here can just as easily be metric, with "easy" spacings based on millimetre or centimetre multiples. Using this technique might let you save the step of drawing the reference lines, but those are handy to have for other steps later, like laying out a chassis drawing.

Now you have the pots and jacks on the board where they should be and on the schematic in relative positions that may or may not promote a good schematic layout. Move them as required to make space for the next few components. Say we drop the tubes in next. 

Depending on how we have constructed our dual-triode symbol, we are either dropping individual triode sections OR dropping a dual-triode with each ADD command. Using the individually requested triode sections allows for an easier to follow schematic that does not have the signal doubling back on itself - the signal flows from left-to-right as it should. When we add the first triode section to the schematic, the entire dual-triode package is dropped into the unconnected component field in the board editor. The next triode section we drop onto the schematic does not change the board editor. The third triode section we drop adds a new duo-triode package to the board. Using the "component" dual-triode, the heater will be a third component that we drop onto the schematic later using the INVOKE tool. It takes two clicks to drop the two triodes onto the schematic, and a later step to connect the heaters, with the potential to forget about the heater wiring, but also for making a neater schematic.

If we have made the duo-triode symbol as exactly that - a dual triode with six connections - then each request for a dual-triode drops the two-section symbol on the schematic and the package onto the board. Most schematics using this symbol approach also have the heater connections within the symbol, so in fact there are nine-connection points made to the single schematic symbol. Where this is a more realistic presentation of the PHYSICAL component, it is NOT really what we want to have on the schematic. The schematic is an abstract representation of the circuit and should make following the signal and power flow EASIER than it is in the real world construction. Having this all-in-one symbol is intuitive but obfuscating at the same time. It allows each 12A_7 to be dropped onto the schematic and board in one click.]]> https://theultimatetone.com/Thread-PCB-schematic-capture-basics-part-1 Fri, 21 Sep 2018 04:48:09 +0000 K O'Connor]]> https://theultimatetone.com/Thread-PCB-schematic-capture-basics-part-1
Using computer software to design printed circuit boards traditionally involves two steps: capturing the schematic, then laying out the board. Technically there is a third step that precedes these which is to make the library of parts, but we will assume here that a device library already exists. In which case, you could still say there is a third step afterwards, which is to generate the Gerber and Excellon files for the PCB house to use to manufacture the board.

Schematic capture is actually YOU manually drawing the schematic in the "schematic editor". 

I've only used Eagle (and Maxi-PC back in 1987) but I would think most PCB design software is more similar than different? In Eagle, you go to the File button, then select New from the drop-down menu, then select Schematic in the second drop-down menu. The schematic editor will open.

Across the top of the window are three tool bars: The top one has file management menus as File, Edit, Draw, View, Tools, Library, Options, Window, Help. Some of these functions are duplicated as icons in the second toolbar, as: folder, Save, Print, Tile, Board/schematic-jog, page sheet-number-window, Use, Script, Run, Zoom functions (full, in, out, redraw) Undo, Redo, Stop, traffic-lights. The third toolbar has just the GRID icon, which is a group of dots (?) and is very important.

For schematic capture, the GRID MUST BE SET TO 0.1" or the connections to the parts will not be made. Right click on the scale icon and the GRID window opens. You see Display on/off which provides grid-lines that are visible or not. Beside this is Style Dots/Lines, where the visible grid indication can be solid lines or lines of dots. It is normal on the schematic to turn the display OFF, in which case it does not matter which style is selected.. Below this is the Size window, where you enter 0.1 and then make sure the default "inch" is visible
Below this is a window called Multiple, which is usually set to 1 (one) and then the Alt window which might be defaulted to 0.01. These are noncritical. Press OK to set the grid.
the scale, zoom functions, 

Down the left-hand side is a tool bar with all the functions available for the schematic editor, in two columns of icons. One of them is the Add function, which looks like a logic AND gate, which is how you access the library of parts. Left-click and a window named ADD opens showing a list of libraries. Scroll through the list. If you know which library has the part you want, left-click on it and it will open and you can see all the parts in that library. Scroll through it and left-click on the part you need. When you do this, the schematic SYMBOL will appear in one of the right-hand boxes within the ADD window, and the PACKAGE will appear in the box beside it. If this is the correct part, then click on OK and the ADD window disappears and the part is now stuck to the cursor in the schematic editor.

Use the mouse to move the part anywhere on the screen you wish, then left click to drop the part. The virtual part is still attached to the cursor allowing you to drop as many of this components onto the schematic as you wish. This is handy when you need a lot of resistors, for example, or capacitors, or any other component. Each part dropped onto the schematic will be assigned a geographic NAME in the sequence of their addition, so if resistors, they will be R1, R2, R3, and so on.

You can MOVE the parts around using the MOVE icon, which is like a compass with an arrow pointing up (north). Left-click on MOVE then cursor to the part you want to move, left click on the part and it is attached to the cursor. If you right-click the part will rotate and stay on the cursor until you left-click again to drop it in place. Each rotational step is 90-degrees, which is appropriate for the schematic as all the connection points on the component, called PINS, must be on the 0.1" grid which is square. 

To connect the components to each other, we draw NETS between them. The NET icon has a hatch-mark line at top that bends and goes down to the right, with three horizontal green lines within. Left-click on this and the third tool-bar along the top will now have options for the wires that you will draw. The first are how the wires can bend, with common default being 90-degrees. The next is orthogonal (45-degrees), then random, and curving options, then the mitre-window, and infill-windows, then Style (Continuous, LongDash, ShortDash, DashDot), and the Net Class ((0-default). Generally, we use the defaults of 90-degree bends, no infill, continuous and 0-default class.

After clicking on the NET icon, we cursor to the pin of one component, then right click, then cursor up or down or sideways as appropriate. There will be a green wire attached to the cursor that will bend where we click until we reach another component pin. We can cursor to any point along the wire we have just laid and make a branching wiring to another component. A dot will appear at the junction when we make the next click on the branch, at a bend or at the next component pin.

Each group of component ends that are tied together is called a "net", short for "network". Each net is assigned a name by Eagle, as N$1, N$2, N$3, and so on. The name of the net is inconsequential to us most of the time and never see these names anyway unless we select the Information icon, or have a reason to rename the nets. We will discuss these things later.

The first time you save the schematic you will be asked where it should be saved and to name the schematic. This is mostly a computer file management issue, following the tree to a point within Eagle where the schematic should be accessible. Eagle has a Projects folder, which is where these things should go. It is a good practice to make a new project folder for your new schematic because you will eventually have a related board and the CAM files needed for manufacturing. That is twelve (12) files overall for the one board, so best to isolate it from your other projects with each in its own project folder.

As you go along adding parts to the schematic, SAVE FREQUENTLY. Eagle likes to crash especially if the computer is older or has been on for a few hours and it would be frustrating to lose hours of work.]]>
Using computer software to design printed circuit boards traditionally involves two steps: capturing the schematic, then laying out the board. Technically there is a third step that precedes these which is to make the library of parts, but we will assume here that a device library already exists. In which case, you could still say there is a third step afterwards, which is to generate the Gerber and Excellon files for the PCB house to use to manufacture the board.

Schematic capture is actually YOU manually drawing the schematic in the "schematic editor". 

I've only used Eagle (and Maxi-PC back in 1987) but I would think most PCB design software is more similar than different? In Eagle, you go to the File button, then select New from the drop-down menu, then select Schematic in the second drop-down menu. The schematic editor will open.

Across the top of the window are three tool bars: The top one has file management menus as File, Edit, Draw, View, Tools, Library, Options, Window, Help. Some of these functions are duplicated as icons in the second toolbar, as: folder, Save, Print, Tile, Board/schematic-jog, page sheet-number-window, Use, Script, Run, Zoom functions (full, in, out, redraw) Undo, Redo, Stop, traffic-lights. The third toolbar has just the GRID icon, which is a group of dots (?) and is very important.

For schematic capture, the GRID MUST BE SET TO 0.1" or the connections to the parts will not be made. Right click on the scale icon and the GRID window opens. You see Display on/off which provides grid-lines that are visible or not. Beside this is Style Dots/Lines, where the visible grid indication can be solid lines or lines of dots. It is normal on the schematic to turn the display OFF, in which case it does not matter which style is selected.. Below this is the Size window, where you enter 0.1 and then make sure the default "inch" is visible
Below this is a window called Multiple, which is usually set to 1 (one) and then the Alt window which might be defaulted to 0.01. These are noncritical. Press OK to set the grid.
the scale, zoom functions, 

Down the left-hand side is a tool bar with all the functions available for the schematic editor, in two columns of icons. One of them is the Add function, which looks like a logic AND gate, which is how you access the library of parts. Left-click and a window named ADD opens showing a list of libraries. Scroll through the list. If you know which library has the part you want, left-click on it and it will open and you can see all the parts in that library. Scroll through it and left-click on the part you need. When you do this, the schematic SYMBOL will appear in one of the right-hand boxes within the ADD window, and the PACKAGE will appear in the box beside it. If this is the correct part, then click on OK and the ADD window disappears and the part is now stuck to the cursor in the schematic editor.

Use the mouse to move the part anywhere on the screen you wish, then left click to drop the part. The virtual part is still attached to the cursor allowing you to drop as many of this components onto the schematic as you wish. This is handy when you need a lot of resistors, for example, or capacitors, or any other component. Each part dropped onto the schematic will be assigned a geographic NAME in the sequence of their addition, so if resistors, they will be R1, R2, R3, and so on.

You can MOVE the parts around using the MOVE icon, which is like a compass with an arrow pointing up (north). Left-click on MOVE then cursor to the part you want to move, left click on the part and it is attached to the cursor. If you right-click the part will rotate and stay on the cursor until you left-click again to drop it in place. Each rotational step is 90-degrees, which is appropriate for the schematic as all the connection points on the component, called PINS, must be on the 0.1" grid which is square. 

To connect the components to each other, we draw NETS between them. The NET icon has a hatch-mark line at top that bends and goes down to the right, with three horizontal green lines within. Left-click on this and the third tool-bar along the top will now have options for the wires that you will draw. The first are how the wires can bend, with common default being 90-degrees. The next is orthogonal (45-degrees), then random, and curving options, then the mitre-window, and infill-windows, then Style (Continuous, LongDash, ShortDash, DashDot), and the Net Class ((0-default). Generally, we use the defaults of 90-degree bends, no infill, continuous and 0-default class.

After clicking on the NET icon, we cursor to the pin of one component, then right click, then cursor up or down or sideways as appropriate. There will be a green wire attached to the cursor that will bend where we click until we reach another component pin. We can cursor to any point along the wire we have just laid and make a branching wiring to another component. A dot will appear at the junction when we make the next click on the branch, at a bend or at the next component pin.

Each group of component ends that are tied together is called a "net", short for "network". Each net is assigned a name by Eagle, as N$1, N$2, N$3, and so on. The name of the net is inconsequential to us most of the time and never see these names anyway unless we select the Information icon, or have a reason to rename the nets. We will discuss these things later.

The first time you save the schematic you will be asked where it should be saved and to name the schematic. This is mostly a computer file management issue, following the tree to a point within Eagle where the schematic should be accessible. Eagle has a Projects folder, which is where these things should go. It is a good practice to make a new project folder for your new schematic because you will eventually have a related board and the CAM files needed for manufacturing. That is twelve (12) files overall for the one board, so best to isolate it from your other projects with each in its own project folder.

As you go along adding parts to the schematic, SAVE FREQUENTLY. Eagle likes to crash especially if the computer is older or has been on for a few hours and it would be frustrating to lose hours of work.]]> https://theultimatetone.com/Thread-PCB-layout-guidelines-for-audio Thu, 13 Sep 2018 14:36:44 +0000 K O'Connor]]> https://theultimatetone.com/Thread-PCB-layout-guidelines-for-audio
There are a few basic guidelines for laying out audio circuits on PCBs (printed circuit boards):

SAVE a lot - every few operations press SAVE so you do not lose hours of work if the program crashes.

NEVER use the AUTO-ROUTER. The auto-routing function is "a big deal" according to the designers of PCB CAD software, but it is entirely useless when laying out audio circuits as it will destroy the proper order of grounding. Galactic Grounding can be applied to PCBs as well as to hand-wired circuits, and is key to achieving a low-noise assembly. Just as with hand-wiring, the ground and power paths on a PCB must be made manually, or "forced" to go where we want them to. It is often easiest to NOT use the GND symbol to achieve this.

Lay out the schematic with normal orientations for the parts, circuits and symbols:
Positive voltage up
Negative voltages down
Ground symbols (if used) pointing down
Signal coming IN from left
NPN transistors with E pointing down*
N-mosfet with S pointing down*
N-jfet with S down*
PNP transistors with E pointing up*
P-mosfet with S pointing up*
P-jfet with S up*
*sometimes these must be rotated horizontal

Keep the signal path as straight as possible inasmuch as signal flow moves from left to right on both the schematic and the board.

Use proper voltage spacing especially for tube circuits. There are conservative and aggressive guides for this and it is better to err on the side of conservative. a good guideline is:
0.00012 x V
V=volts
measurement is in inches
solder mask applied
0.001" = 1-mil (milli-inch). The above equation can be done in mils as 0.12 x V = mils. It is easier to refer to a trace width or space as 16-mil, 40-mil, etc.
Without a solder mask (which is pretty unusual today) the equation becomes V / 0.001
When checking the board, turn on the GRID and set it to a small increment and count the divisions between traces, then divide by 0.12 for a spacing in V. For example, a spacing of 40-mil provides 40 / 0.12 = 333V. If you know the voltage spacing you need, multiply V x 0.12 for mils. For example, 500V needs 500 x 0.12 = 60-mils.

Use appropriate track WIDTH. You can select the track WIDTH on the fly, before you lay the trace, or change it afterwards. Track WIDTH determines current capacity and it is surprising how much current a narrow trace will handle.

More to follow.]]>
There are a few basic guidelines for laying out audio circuits on PCBs (printed circuit boards):

SAVE a lot - every few operations press SAVE so you do not lose hours of work if the program crashes.

NEVER use the AUTO-ROUTER. The auto-routing function is "a big deal" according to the designers of PCB CAD software, but it is entirely useless when laying out audio circuits as it will destroy the proper order of grounding. Galactic Grounding can be applied to PCBs as well as to hand-wired circuits, and is key to achieving a low-noise assembly. Just as with hand-wiring, the ground and power paths on a PCB must be made manually, or "forced" to go where we want them to. It is often easiest to NOT use the GND symbol to achieve this.

Lay out the schematic with normal orientations for the parts, circuits and symbols:
Positive voltage up
Negative voltages down
Ground symbols (if used) pointing down
Signal coming IN from left
NPN transistors with E pointing down*
N-mosfet with S pointing down*
N-jfet with S down*
PNP transistors with E pointing up*
P-mosfet with S pointing up*
P-jfet with S up*
*sometimes these must be rotated horizontal

Keep the signal path as straight as possible inasmuch as signal flow moves from left to right on both the schematic and the board.

Use proper voltage spacing especially for tube circuits. There are conservative and aggressive guides for this and it is better to err on the side of conservative. a good guideline is:
0.00012 x V
V=volts
measurement is in inches
solder mask applied
0.001" = 1-mil (milli-inch). The above equation can be done in mils as 0.12 x V = mils. It is easier to refer to a trace width or space as 16-mil, 40-mil, etc.
Without a solder mask (which is pretty unusual today) the equation becomes V / 0.001
When checking the board, turn on the GRID and set it to a small increment and count the divisions between traces, then divide by 0.12 for a spacing in V. For example, a spacing of 40-mil provides 40 / 0.12 = 333V. If you know the voltage spacing you need, multiply V x 0.12 for mils. For example, 500V needs 500 x 0.12 = 60-mils.

Use appropriate track WIDTH. You can select the track WIDTH on the fly, before you lay the trace, or change it afterwards. Track WIDTH determines current capacity and it is surprising how much current a narrow trace will handle.

More to follow.]]> https://theultimatetone.com/Thread-PCB-design-for-guitar-amps Wed, 22 Aug 2018 19:09:02 +0000 K O'Connor]]> https://theultimatetone.com/Thread-PCB-design-for-guitar-amps
Printed circuit board (PCB) use is not new to guitar amp fabrication; just look at Marshall amps built since 1965 or so, or to Ampeg amps from the same era, let alone countless other brands.

PCBs offer consistent unit-to-unit performance by eliminating variations of stray capacitance and stray inductance - the "parasitic" elements of the physical construction.

There is NO reliability difference between a properly laid out and assembled PCB and a properly laid out and assembled hand-wired amp.

We will discusss using PCB design software such as Eagle, and the basic things to be mindful of in using PCBs for guitar amp construction - really, for construction of any device.

Have fun]]>
Printed circuit board (PCB) use is not new to guitar amp fabrication; just look at Marshall amps built since 1965 or so, or to Ampeg amps from the same era, let alone countless other brands.

PCBs offer consistent unit-to-unit performance by eliminating variations of stray capacitance and stray inductance - the "parasitic" elements of the physical construction.

There is NO reliability difference between a properly laid out and assembled PCB and a properly laid out and assembled hand-wired amp.

We will discusss using PCB design software such as Eagle, and the basic things to be mindful of in using PCBs for guitar amp construction - really, for construction of any device.

Have fun]]>