Downloads related to the Linear Audio Cube-law amplifier

NEW Updated Supplement 2+ March 2017 -- Thermal SOA using a Vbe multiplier to control the clip level if the MOSFET's get too hot. It allows ONE pair of MOSFET's (was two pair) for 100W and no need for the fuse in the speaker line. Several other useful circuit developments (not covered in the Addendum) can be added to the free Linear Audio PCB.

To download Supplement 2+ go to 'A3 Downloads' tab 

1. How to download LTspice files to simulate the Linear Audio Vol.8 Cube-law amplifier.

Unfortunately, Zip files cannot be posted on at this site due to Jimdo restrictions on certain file types for this free site. Look in this G-drive link,or E mail me using Contact and I'll email your the latest Zip files for simulations.

2. Download a User Guide for simulating the above LTspice cube-law amp circuit files

How to simulate the Cube Amp using LTspice
Loads of info on how to simulate and use the two jigs (Anylaw jig and EKV fittng jig)
Adobe Acrobat Document 1.1 MB


3. Download a 40 page supplement to the Linear Audio Cube-law Amp article (Vol.8)

Original Linear Audio Vol.8 article Supplement 1
Additional material on how a Cube-law amp works and why cube-law-AB is virtually crossover distortion free. More on the SOA design, driver design, how PC works, compensation, soft clipping distortion simulations and PC phase reversal effects reported in listener tests.
[This Supplement has been rewritten and is now Supplement 2+ -- see A3 downloads].
Adobe Acrobat Document 1.1 MB


4. Download article ref. #4 (for private use only)

J. Ramirez-Angulo, et al, ‘Applications of composite BiCMOS transistors’, ISCAS 1992, p1262-65
Adobe Acrobat Document 704.3 KB

5. Download a LTE in Electroncs World Feb 1994 by Ivor Brown (referenced in Supplement)


Adobe Acrobat Document 66.3 KB

6. Download a LTE in Electroncs World Apr 1996 by Douglas Self (referenced in Supplement)

Adobe Acrobat Document 114.6 KB

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7. Added Oct 2014>>Download the Willy Sansen distortion tutorial

Adobe Acrobat Document 1.3 MB

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8. Added Oct 2014>>Download LTspice files for 19kHz+20kHz CCIF IM Cube-law amp simulations plots in Linear Audio Letters to the Editor October 2014 are now here.

9. Added Aug 2015>>Letter to the Editor of Linear Audio in response to Steve Conner's queries a.k.a. Scopeboy at around 6th October 2014, with a postscript: IMD tests courtesy of Jan Didden March 2015. Download from here.

10. Added Mar 2016>>Ivor Brown, 'Audio Power, FETs and feedback', E&WW Apr 1990 p343-349. This article has a FET output stage (Common Source with voltage gain) that out-performs all the conventional power amp designs popularised by Douglas Self over the next 25 years. Still, 25 years on, very few designers have noticed Ivor Brown's topology -- Common Source with voltage gain, and it doesn't use Miller compensation.

Ivor Brown's article: A sensibly-driven FET power amp, EW-WW April 1990
Adobe Acrobat Document 2.1 MB

11. Added Sep 2016>>Studio 350 Power Amp, SC Jan 2004. A rare example of SOA design taking into account the case temperature of the transistors. To read set Acrobat to View>RotateView>CW.

Adobe Acrobat Document 4.3 MB