Hello,
I'm currently working on a small project for school where I shall compare distorsion in Class A and Class A/B amplifiers.
I have decided to use a John Linsley Hood construction for my class-A amp and am thinking of building the Trimodal Amplifier by Douglas Self for comparison. I have the circuit in print in the book "Audio Power Amplifier Design Handbook" but would prefer to have it in digital form. I have searched for it on the net, but to no avail. Does anyone know where I can find it?
Also if anyone have Spice3-models of it and are willing to share it I'd be very happy.
I'm also searching for a good program to draw circuit diagrams, currently I use xfig but it is not very convenient to work with. My computer is an iBook with Mac OS X, that means I can run all BSD/Linux programs but not old macintosh applications. Since I only have low-level education and are rather young, I'm not qualified to a student-license, so the application can't be very expensive, free would be preferable.
Thanks in advance
Nils Mattisson
Sweden
I'm currently working on a small project for school where I shall compare distorsion in Class A and Class A/B amplifiers.
I have decided to use a John Linsley Hood construction for my class-A amp and am thinking of building the Trimodal Amplifier by Douglas Self for comparison. I have the circuit in print in the book "Audio Power Amplifier Design Handbook" but would prefer to have it in digital form. I have searched for it on the net, but to no avail. Does anyone know where I can find it?
Also if anyone have Spice3-models of it and are willing to share it I'd be very happy.
I'm also searching for a good program to draw circuit diagrams, currently I use xfig but it is not very convenient to work with. My computer is an iBook with Mac OS X, that means I can run all BSD/Linux programs but not old macintosh applications. Since I only have low-level education and are rather young, I'm not qualified to a student-license, so the application can't be very expensive, free would be preferable.
Thanks in advance
Nils Mattisson
Sweden
Hi,
Here you will find "DesignWorks Lite". It is one of the best and easy to use schematic drawing programs I’ve ever seen. Price is $39,95. But to my opinion it is definitely worth the money. Anyway you have a free trail of 30 days:
http://www.capilano.com/
Here you will find "DesignWorks Lite". It is one of the best and easy to use schematic drawing programs I’ve ever seen. Price is $39,95. But to my opinion it is definitely worth the money. Anyway you have a free trail of 30 days:
http://www.capilano.com/
Here's a schematic drawing package that I think is pretty good and its trial version is free: http://www.spectrum-soft.com/index.shtm
I am wondering why you want to build two different amplifier circuits to compare class A and class B. Won't it be difficult to know which distortion differences are due to the class and which are due to the design? Have you considered building just a single circuit and changing its output bias current to change it from class B to class A?
BAM
I am wondering why you want to build two different amplifier circuits to compare class A and class B. Won't it be difficult to know which distortion differences are due to the class and which are due to the design? Have you considered building just a single circuit and changing its output bias current to change it from class B to class A?
BAM
Nils was actually asking for software for an IMac and OS X. DesignWorks is native Mac software and it is very good.
"Good point, but isn't Douglas Self's Trimodal Amplifier switchable between class A and class B (and class AB). So you only need to build this one."
Indeed it is.
I will go on and say I cannot hear, or measure the differences when set up this way. UUT could put out 15W in A mode and 70W in AB. THD less than 0.002% either way.
Funny thing was the IMD was actually lowest with the bias set at ~20mA. I think this is what Self is refering to as 'optimally biased class B'.
Indeed it is.
I will go on and say I cannot hear, or measure the differences when set up this way. UUT could put out 15W in A mode and 70W in AB. THD less than 0.002% either way.
Funny thing was the IMD was actually lowest with the bias set at ~20mA. I think this is what Self is refering to as 'optimally biased class B'.
Pjotr said:
I did some work for one of the guys (and met the son) who started this (probaly one of the guys still) and they indeed are top notch -- i owned, and never used, a very early version of this.
I use VectorWorks (general CAD) for doing my schematics, but it doesn't qualify as cheap. There are a couple budget CAD programs, the one i can actually put my fingers on is Cadintosh by the same guys who do GraphicConverter. A Carbon version is available.
It would also be a good idea to scan thru Made4Mac and download.com. A good PCB layout program can be had from Osmond -- a carbon version of that is also available.
dave
Free schematic capture:
http://xcircuit.ece.jhu.edu/index.html
I can't vouch for this because I haven't tried it, but the price is right, and it looks like the author continues to maintain it.
http://xcircuit.ece.jhu.edu/index.html
I can't vouch for this because I haven't tried it, but the price is right, and it looks like the author continues to maintain it.
Hi Dave,
In the late 80ties I did an extensive search for CAD software for the Mac. In those days the people at Capilano were the only ones that understood that hardware people are working completely different than software people. So they came up with a piece of software (DesignWorks) that was easy to use by hardware people and relatively bug-free. Later on they came with a nice Mac version of ABEL, a PLD design package originally developed by DATA IO. In those days there was only some crude DOS software, programmed to the “bare steel”, or there was software for Unix mainframes costing tons.
I still use a 68k version (V3.5) running on Basilisk for quick setting up prototyping schematics. Once you have made your own collection of libs it works pretty fast. I also still use it for schematics that have to go in print. When printed to a .ps file is can be easily imported in AI for touch-up.
IMO their software is still standing out the mass out there when you concern the price, graphics capabilities and ease of use. But it is schematic capture only.
When working on a win-system I would recommend using the already mentioned SpectraSoft software. The schematics capture part is also good and easy to use and it is FREE.
--------------------------------------------------
Nils, are you still there?
Attached the schematic of the tri-modal amp I have found. It is not of my own so I can’t take responsibility for it.
Chaio
In the late 80ties I did an extensive search for CAD software for the Mac. In those days the people at Capilano were the only ones that understood that hardware people are working completely different than software people. So they came up with a piece of software (DesignWorks) that was easy to use by hardware people and relatively bug-free. Later on they came with a nice Mac version of ABEL, a PLD design package originally developed by DATA IO. In those days there was only some crude DOS software, programmed to the “bare steel”, or there was software for Unix mainframes costing tons.
I still use a 68k version (V3.5) running on Basilisk for quick setting up prototyping schematics. Once you have made your own collection of libs it works pretty fast. I also still use it for schematics that have to go in print. When printed to a .ps file is can be easily imported in AI for touch-up.
IMO their software is still standing out the mass out there when you concern the price, graphics capabilities and ease of use. But it is schematic capture only.
When working on a win-system I would recommend using the already mentioned SpectraSoft software. The schematics capture part is also good and easy to use and it is FREE.
--------------------------------------------------
Nils, are you still there?
Attached the schematic of the tri-modal amp I have found. It is not of my own so I can’t take responsibility for it.
Chaio
BAM: That is why I plan to build the Douglas Self design. If I understood it correct it is very easy to switch between Class-A,A/B,B. The JLH-amp is mainly for the fun of it (don't tell my teacher though ).
Concerning the software, I checked Designworks and it seems to me that the Liteversion of it isn't available for OS X yet, the Proversion is too expensive to me.
I also checked Eaglesoft and since it doesn't include the sourcecode it will probably be though to get it running.
Xcircuit seems promising, I will have to take a closer look at it.
I stumbled across a program called GNU Electric which seems very good, it can even autogenerate Spice3 files, problem is only that it is a tad buggy. I compiled and started it successfully but all of the menus were lost so it's not usable yet. According to the author (Steven Rubin) the bugs will be ironed out in the next version which should be available in a month. Osmond will work for the PCB layout, when I get so far.
Pjotr: Thanks for the schematic, it will save me a lot of time. It is not completely identical to the one found in my book (Audio Power Amplifier Design Handbook, Douglas Self) but the differences are minor so I will be able to use it.
Thanks for all of the replies.
/Nils
).Concerning the software, I checked Designworks and it seems to me that the Liteversion of it isn't available for OS X yet, the Proversion is too expensive to me.
I also checked Eaglesoft and since it doesn't include the sourcecode it will probably be though to get it running.
Xcircuit seems promising, I will have to take a closer look at it.
I stumbled across a program called GNU Electric which seems very good, it can even autogenerate Spice3 files, problem is only that it is a tad buggy. I compiled and started it successfully but all of the menus were lost so it's not usable yet. According to the author (Steven Rubin) the bugs will be ironed out in the next version which should be available in a month. Osmond will work for the PCB layout, when I get so far.
Pjotr: Thanks for the schematic, it will save me a lot of time. It is not completely identical to the one found in my book (Audio Power Amplifier Design Handbook, Douglas Self) but the differences are minor so I will be able to use it.
Thanks for all of the replies.
/Nils
Dave,
You don’t know of Basilisk BasiliskII is an open source 68k Macintosh emulator:
http://www.uni-mainz.de/~bauec002/B2Main.html
An OS X port:
http://www.users.bigpond.com/pear_computers/
And a Win port:
http://gamma.nic.fi/~lpesonen/BasiliskII/
For both you need an image file of an original Mac ROM. Extraction software is provided if you own a 68k Mac. ROM’s with checksum F1A6F343 (general 1 MB rom) is working without any problems.
Oops Nils you are right, no DesignWorks Lite for OS X If you are still interested, send them an e-mail. I can’t imagine they will not port it to OS X in the near future.
You don’t know of Basilisk
BasiliskII is an open source 68k Macintosh emulator: http://www.uni-mainz.de/~bauec002/B2Main.html
An OS X port:
http://www.users.bigpond.com/pear_computers/
And a Win port:
http://gamma.nic.fi/~lpesonen/BasiliskII/
For both you need an image file of an original Mac ROM. Extraction software is provided if you own a 68k Mac. ROM’s with checksum F1A6F343 (general 1 MB rom) is working without any problems.
Oops Nils you are right, no DesignWorks Lite for OS X
If you are still interested, send them an e-mail. I can’t imagine they will not port it to OS X in the near future.
Pjotr said:You don’t know of Basilisk
Thanx for that. I knew there were a couple emulators kicking around, i tried one it wouldn't work and i wasn't motivated enuff to pursue it -- i have a 100MHz '040 machine for running the one old piece of software i need (breaks in OS newer than 7.6 or machines with >16 MB RAM, log charts require System 6)-- but it would be nice to be able to run it on my G4 in X.
dave
As an admirer of Lemke (based on their excellent work with GraphicConverter), I purchased Cadintosh. I was in particular attracted by the claims of "numeric entry", as this is how I design. But after having tried Cadintosh, I would suggest that you avoid it, as it is neither easy nor intuitive to use.
IMO, a wiser purchase would be an old copy of ClarisCad (although I haven't tried this on the newer Mac OS versions). I don't know what the ultimate capablities of ClarisCad are, but at least you will spend most of your time actually designing, rather than fighting the program.
If you can afford it, VectorWorks is a truly wonderful CAD program. I use it for all of my mechanical design work (all of the upcoming Lyra cartridges have been designed with VectorWorks). Admittedly, it costs upwards of US$800, but it is intuitive (you don't have to memorize lots of arcane commands,) and it is easy to use and will save you lots of time (and frustration).
But VectorWorks isn't really suited for schematic capture. In fact, when it comes to schematic capture on the Mac, I don't know if there are _any_ programs worth recommending. Maybe the older versions of B2Spice or Electronic Workbench (although for serious work, the simulator in EWB is a bad joke).
Although I am far from being a fan of Windows, you may be ahead by investing in a cheapie WinPC and using it as an EDA-only workstation, or maybe VirtualPC (if you have a fast Mac) would do the trick.
Most of my electronic design and layout work is done on a Win2K PC in Protel 98, including the final board versions of my 3-dimensional air-dielectric layouts (I do a fair amount of this work in VectorWorks to get the mechanical perspective). If you are willing to customize it, fill in its inadequacies and devise lots of tricks for it, Protel is capable enough. But it is neither cheap nor easy to use.
I would like to upgrade to Protel DXP, but my piggy-bank is still woefully short of pennies...
regards, jonathan carr
IMO, a wiser purchase would be an old copy of ClarisCad (although I haven't tried this on the newer Mac OS versions). I don't know what the ultimate capablities of ClarisCad are, but at least you will spend most of your time actually designing, rather than fighting the program.
If you can afford it, VectorWorks is a truly wonderful CAD program. I use it for all of my mechanical design work (all of the upcoming Lyra cartridges have been designed with VectorWorks). Admittedly, it costs upwards of US$800, but it is intuitive (you don't have to memorize lots of arcane commands,) and it is easy to use and will save you lots of time (and frustration).
But VectorWorks isn't really suited for schematic capture. In fact, when it comes to schematic capture on the Mac, I don't know if there are _any_ programs worth recommending. Maybe the older versions of B2Spice or Electronic Workbench (although for serious work, the simulator in EWB is a bad joke).
Although I am far from being a fan of Windows, you may be ahead by investing in a cheapie WinPC and using it as an EDA-only workstation, or maybe VirtualPC (if you have a fast Mac) would do the trick.
Most of my electronic design and layout work is done on a Win2K PC in Protel 98, including the final board versions of my 3-dimensional air-dielectric layouts (I do a fair amount of this work in VectorWorks to get the mechanical perspective). If you are willing to customize it, fill in its inadequacies and devise lots of tricks for it, Protel is capable enough. But it is neither cheap nor easy to use.
I would like to upgrade to Protel DXP, but my piggy-bank is still woefully short of pennies...
regards, jonathan carr
jcarr said:
That is good to know. Never tried it myself... like you i assumed given Graphic Convertor that it should be half decent.
Allen Wright uses ClarisCad for his drawing needs. He is running under 9.1 (IIRC) but it is necessary to run it out of a less than 2 GB disk partition.
What is the difference between schematic capture & just drawing schematics (which is what i do with VW)? I've been using VW since before the Mac II, so am fairly comfortable with it.
dave
Dave:
>Like you I assumed given Graphic Convertor that it should be half decent.<
Considering its parentage, I assumed that Cadintosh would be a prince, but the actual results were much closer to a frog.
>Allen Wright uses ClarisCad for his drawing needs.<
I think I recall Allen mentioning this when I met him at the Frankfurt Hi-End show. Although I haven't used ClarisCad for schematic work, nor for layouts, I have used Adobe Illustrator to do radial-style pcb layouts (for example, switched attenuator & star-grounding boards).
>What is the difference between schematic capture & just drawing schematics?<
Drawing schematics can be done with any type of drawing program, provided that you are willing to make up symbols for all of the components that you want to use.
Schematic capture is sometimes done just for memorandum purposes (to see how something looks when you have worked out the pertinent details), but its normal role is as the front-end editor for exporting the electrical data to other programs, such as simulators or PCB layout editors. Therefore, a schematic capture program will treat lines as electrical connections instead of as just lines, and will include ways of tying the schematic symbol data to simulation models and/or physical footprints.
For simulation purposes, there should be links from the schematic capture program to a symbol editor that can assign electrical meaning to a schematic symbol and its individual pins as well as modifying the symbol shape, and a model editor that can be used to define the component's simulation characteristics. For layout work, there should be links to a footprint editor that can assign electrical meaning to individual pads of a footprint as well as modifying the footprint shape. It is also good to have back-annotation (so that changes made in the various editors can automatically be reflected in all open schematics).
Once you have simulated your schematic, and are satisfied wih the results, the schematic-capture front-end will export all of the electrical data to the PCB editor in the form of a "net-list". The netlist will tie all of the component footprint pads together according to the electrical connectivity you have defined in the schematic, and insures that you make no connection errors in the layout. If you need extra help in completing your design, the netlist is also used to drive other components like rule-violation checkers and auto-routers.
hth, jonathan carr
>Like you I assumed given Graphic Convertor that it should be half decent.<
Considering its parentage, I assumed that Cadintosh would be a prince, but the actual results were much closer to a frog.
>Allen Wright uses ClarisCad for his drawing needs.<
I think I recall Allen mentioning this when I met him at the Frankfurt Hi-End show. Although I haven't used ClarisCad for schematic work, nor for layouts, I have used Adobe Illustrator to do radial-style pcb layouts (for example, switched attenuator & star-grounding boards).
>What is the difference between schematic capture & just drawing schematics?<
Drawing schematics can be done with any type of drawing program, provided that you are willing to make up symbols for all of the components that you want to use.
Schematic capture is sometimes done just for memorandum purposes (to see how something looks when you have worked out the pertinent details), but its normal role is as the front-end editor for exporting the electrical data to other programs, such as simulators or PCB layout editors. Therefore, a schematic capture program will treat lines as electrical connections instead of as just lines, and will include ways of tying the schematic symbol data to simulation models and/or physical footprints.
For simulation purposes, there should be links from the schematic capture program to a symbol editor that can assign electrical meaning to a schematic symbol and its individual pins as well as modifying the symbol shape, and a model editor that can be used to define the component's simulation characteristics. For layout work, there should be links to a footprint editor that can assign electrical meaning to individual pads of a footprint as well as modifying the footprint shape. It is also good to have back-annotation (so that changes made in the various editors can automatically be reflected in all open schematics).
Once you have simulated your schematic, and are satisfied wih the results, the schematic-capture front-end will export all of the electrical data to the PCB editor in the form of a "net-list". The netlist will tie all of the component footprint pads together according to the electrical connectivity you have defined in the schematic, and insures that you make no connection errors in the layout. If you need extra help in completing your design, the netlist is also used to drive other components like rule-violation checkers and auto-routers.
hth, jonathan carr
jcarr said:
Thanx for that excellent explanation...
One would hope for some of the UNIX software that does this getting ported to OS X eventually since OS X now represents the largest installed base of UNIX machines.
dave
And just this morning i was reminded of another potential schematic drawing program -- Concept Draw. I have gotten as far as downloading the trial, but haven't tried it yet.
dave
trimodal pcbs
If you are not doing the PCBs yourself *because you can*, they are available here, albeit at a price:
http://www.signaltransfer.freeuk.com/trimodal.htm
Jake
If you are not doing the PCBs yourself *because you can*, they are available here, albeit at a price:
http://www.signaltransfer.freeuk.com/trimodal.htm
Jake
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