ax-Amplifier

The ax-Amp has been moved to the ‘Projects’ page – you can find a link to the shop for PCB’s in there.

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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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Ground Loops

Updated with new material 7th January 2019 This set of c. 70 slides is the culmination of my experience over a period of about 25 years building numerous power amplifiers and preamplifiers. I first started out in audio around 1975 or 76 as a teenager. Some of my creations were reasonably quiet – through pure […]

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How to wire-up a Dual Mono Bloc Amplifier

A few people have asked about wiring up a dual mono amp aka dual mono bloc. In a dual mono bloc there are separate power supplies and lots of opportunity for cross channel ground loops and ordinary ‘classic’ ground loops as well. This wiring scheme addresses the situation were unbalanced connections between the source equipment […]

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Amplifier History: The JBL SA-600

The beautifully styled JBL SA-600 amplifier was launched by the James B. Lansing company in 1966, and Bart Locanthi (the designer) wrote the  technical article linked to at the bottom of this write-up in January 1967. I’ve included this in the hifisonix power amplifier library because it is one of the earliest – if not […]

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