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Category: Projects
The ax-Amplifier: A Very High-Performance 60W RMS Class A Amplifier featuring AFEC
Parts 1 and 2 of the ax-Amplifier were published in the April and May 2024 issues of US based audioXpress magazine. Part 1 – The ax-Amplifier Part 2 – The ax-Amplifier Click on the link to get the supplementary data (BOM etc) from audioXpress Click this link to order 2 off ax- Amplifier PCB’s https://hifisonix.com/shop/2-off-ax-amplifier-module-pcb/…
Imroved Soft Start + DC Blocker aka iSSDCB
The original Soft Start + DC Blocker published on this website a few years ago required quite complex wiring encompassing both the mains supply to the transformer and wiring from the rectified and DC-smoothed secondary. Additionally, the mains power switch had to be rated for the full primary AC load current which placed severe limitations…
Hifisonix X-Altra Mini II Line Preamplifier with Remote Control (Deprecated)
The X-Altra Mini II has been discontinued as a complete project. The individual PCBs are still available over in the shop however and are great line stages and power supplies. The X-Altra Mini II is a superb preamplifier and it sits at the heart of my system, but it was complex with lots of inter-module…
Hifisonix kx2 Class A Current Feedback Amplifier
The 15W RMS (28W peak class A) kx2-Amplifier offers outstanding noise and distortion performance and is specifically designed for driving high efficiency speakers in average to large listening spaces but also performs well driving more normal efficiency speakers in restricted listening spaces. Please note the kx2-Amplifier PCBs are supplied by Jim’s Audio. You can buy…
Hifisonix X-Altra MC/MM RIAA Phono EQ Preamp
The X-Altra MC/MM phono preamp, whether bought as a completed unit or DIY built, delivers the ultimate performance with respect to noise, overload, and RIAA conformance, placing it among the very best available anywhere at any price. In 2021, the design was featured in audioXpress, a leading audio industry publication based in the US. Part…
Hifisonix nx-Amplifier: A High Performance 100 W Class AB Current Feedback Amplifier
Originally published in December 2012. This power amp design is based on the sx-Amplifier topology, but with the TIS and output stage re-configured for class AB operation, enabling it to deliver 100 W into 8 Ohms. I have kept the design very simple, retaining the CFA topology, providing a very wide -3 dB bandwidth of…
Hifisonix sx-Amplifier: A 15 W Class A Current Feedback Amplifier
Originally published in August 2012. Update January 2018: For the sx-Amplifier, you can buy a complete set of very high quality Double Sided THP Gold Flashed PCB’s from Jim’s Audio here: sx-Amplifier DS THP PCB Set About 150 sx-Amplifiers have been built world-wide. As you can read about in the PDF below, my class A…
Hifisonix High Performance Balanced Line Stage
Click here to buy a stereo PCB for this line stage over in the Shop. Click here for the schematic Click here for the BOM Click here for some measurements of the Balanced Line Stage This compact OPA1641 and OPA1642 board is the perfect building block around which to build a high-performance line stage. Here…
Hifisonix Discrete JFET Input Line Stage
This discrete JFET input line stage can drive a 2k ohm load to 6V RMS in class A at less than 30 ppm distortion and at 3V RMS into 2k ohms, the distortion is around 7ppm at 1 kHz. The output stage runs at 20mA standing current. A jumper allows the user to select either…
Hifisonix Micro Ripple Eater
Click here to buy a Micro Ripple Eater PCB in the Shop This simple ripple eater (aka MRE) can deliver up to 10A per supply rail (provided it is suitably heatsinked!) and will reduce mains related ripple on amplifier supply rails by up to 40 dB and as much as 50 dB at HF. The…