The ax-Amp: a 60W RMS class A Current Feedback Amplifier

Click this link to order 2 off ax- Amplifier PCB’s https://hifisonix.com/shop/2-off-ax-amplifier-module-pcb/ Part 2 of the ax-Amplifier has just been published in audioXpress, 15th April, covering the power supply, power control, mechanical assembly and wiring, followed by detailed measurements. Here is a short synopsis provided from the AX website:- Click on the link to visit audioXpress […]

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nx2-Amplifier Update

April 18th Update: The first nx2 proto board has been assembled and basic DC tests completed. This covers output stage quiescent current adjustment, DC offset adjustment and checking that all the DC voltages are correct, along with basic stability testing i.e. no oscillation. The next step will be to take an initial look at the […]

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CFA vs. VFA: A Short Primer For the Uninitiated

This article was written in 2014 in response to what can only be described as a vitriolic debate as to what constituted a CFA on diyAudio.com.  At the time, many of the participants were struggling to grasp the fundamental differences between VFA’s and CFA’s, and even how to tell them apart.  So, this document is […]

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AN-597 Current Feedback Amplifiers

This National Semiconductor application note was written by Hans Palouda and published in 1989. It explains basic CFA operation clearly and concisely. AN-597 Current Feedback Amplifiers Here are some other useful application notes and articles that may help in developing an understanding of amplifier topologies and their associated trade-offs. wiki https://en.wikipedia.org/wiki/Current-feedback_operational_amplifier EDN https://www.edn.com/design/analog/4458753/In-defense-of-the-current-feedback-amplifier ADI https://www.analog.com/media/en/training-seminars/tutorials/MT-034.pdf TI https://cas.ee.ic.ac.uk/people/dario/files/E416/OA-30.pdf     […]

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CFA’s: An Intuitive Analysis from Intersil

This application note from Intersil provides a simple and easy to understand explanation about CFA operation   CFA – An Intuitive Analysis

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Hifisonix kx-amplifier now replaced with the new kx2-Amplifier

If you have purchased PCB’s and are still constructing your kx-Amplifier, I will continue to fully support your efforts as required, so do not worry. 114 PCB sets of the kx-Amplifier were sold, with as far as can be ascertained, a large proportion of them being built.  Unfortunately  6 of the builders reported oscillation problems […]

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