Additional material for Hegglun Cube Law power amp

In his Volume 8 article on Cube Law power amplifiers Ian Hegglun mentions that he has a lot of additional information available on the subjet. This additional info can be accessed on line courtesy of Mason Green. There's even more info and also the possibility to get additional PCBs from Mason at his own site.

As if that is not enough, there's more interesting info Ian collected including simulation models and files to simulate his amp with LTspice...


In his article on Audio Equalisation in Volume 7, Malcolm Hawksford provided three Appendices. These contain Matlab scripts that can be used to explore the various circuit concepts described in the article.

Those Appendices can be downloaded in text format for immediate use in Matlab or any of it's equivalent applications.


Testing One, Two, Three...

Stuart Yanigers' Linear Audio Volume 2 article with this title has drawn considerable interest from both audio professionals as well as serious amateurs and hobbyists.

Many readers requested to make it available on line, so here it is.



High Octane phono preamp

In Vol 6, Hannes Allmaier published his Peter Baxandall - inspired High Octane phono preamp. To facilitate building this preamp, Hannes gives some building tips and lists the Bill of Material. He also graceously provided the Gerber files for manufacturing the PC board for personal/study use. A picture of the populated prototype PCB is here. Please contact Hannes for any commercial use of this project.


LSJ74B preliminary data sheet

Linear Systems has send me the preliminary data sheet for the LSJ74B, the long-awaited replacement for the discontinued Toshiba 2SJ74B. This is posted here for the benefit of those who purchased Linear Audio Vol 6 asnd received a free LSJ74B and LSK170B.


BoM for Putzeys demo preamp Linear Audio Vol 5

Our friend Paul Hendriks from The Netherlands build Bruno Putzeys' demo preamp project from Linear Audio Vol 5. He produced a complete BoM which can be sourced one-stop from distributor Farnell. Even if you want to buy from another distributor, the complete list with manufacturing codes will be very usefull. With thanks to Paul.


Power Supply for Gary Galo's  Archival Phono Preamp

Gary Galo's article in Vol 5, "An Archival Phono Preamp" mentioned that a suitable power supply would be posted online - here it is.

It is based on the Jung/Didden regulator published in Audio Amateur in 1995, amended by Walt Jung's article in issue 4/2000 in Audio Xpress. The original articles can be downloaded from Walt's web site.


Gerbers and PCB layout for Bruno Putzeys' article in Vol 5

The article from Bruno Putzeys in Vol 5 'The G-word, or, how to get your audio off the ground' is accompanied by a complimentary PCB for the demo project (courtesy It's a busy PCB and to help with parts placement, a larger version of the stuffing guide, the top layer and the bottom layer is available here. The Gerbers can also be downloaded if you want to make your own.


Patrick K. (aka EUVL) wrote an interesting article for Vol 3, "Design Considerations for a Class A Amplifier Enclosure". This is an subject that is very rarely treated at all. The article gives a complete treatment of all involved issues and can be used as a procedure to calculate the required heatsink capacity for a project, as well as selecting a suitable product to mee those requirements. Therefor, Patrick and I have agreed to place it online for further dissemination.


Color graphs for Jack Walton's regulator article in Vol 4

Linear Audio Volume 4 has a long-awaited article by Jack Walton, comparing a large number of low power supply regulators. Comparison includes measurements and controlled listening tests by the New Jersey Audio Club.

The article has a several rather busy graphs with curves in various shades of grey. The readability could be better, so I regenerated those graphs in color and posted them here on-line.

Fig 5, positive regulators Line Rejection

Fig 6, negative regulators Line Rejection

Fig 7, positive regulators Output Noise

Fig 8, positive regulators Output Impedance

Fig 9, negative regulator Output Impedance



MathCad resources for the audio enthousiast

Update 5 July 2012: Mason Green send me some info on an alternative to MathCad/MatLab: Scientific Python. He included a link to an excellent tutorial on Scientific Python. For an example of a practical application of Scientific Python, see Mason's PORC (Python Open Room Correction) project. Thank you Mason!
There have been several articles in Linear Audio supported by MathCad calculations and graphs; Burkhard Vogel's articles come to mind. If you are the curious type you probably discovered that a MathCad license can set you back $ 1500 or so. Not really DIY territory. However, here's a well kept secret: the student/educational version of MathCad is available for less than $ 100 and is identical to the expensive version, the only difference being that you don't get on-line support. And you need a professor- or student ID to be able to buy that version.
But it gets still better: if you buy Brent Maxfields'book Essential MathCad for Engineering, Science and Math for less than $ 50 you get an included MathCad 15 one-year student license for free. And the book is a great reference to the application so you can do without the on-line support. For beginners, I recommend Stephen P. Tubbs' MathCad for Electrical Engineers and Technologists. This last book takes you in slowly with calculating and graphing things like the current in a C-R circuit, for example. Both books are highly recommended! Note: the Maxfield book was published in 2009 so I don't know how many copies are still on offer.
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