My Beautiful Michell Gyrodec SE

I bought my turntable in 2016, having read about Michell turntables on and off for more than 20 years. While working in Taiwan between 2011 and 2015, I visited a local Audio shop in Tianmu, Taipei where a full Gyrodec within its Perspex case was on display. It was a huge piece of machinery, but […]

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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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Using the QuantAsylum QA401 for accurate Audio Measurements

The QA 401 from QuantAsylum (superseded by a newer, improved QA 402 and now the QA403) has emerged as a popular, comprehensive audio test instrument in the DIY audio fraternity and the go to instrument in many cases for commercial production testing in the audio industry. It combines a first rate DAC and ADC with […]

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Building Quiet Audio Power Amplifiers Requires Best Wiring and Layout Practices

There is a misconception that noise pickup is reduced by placing the input RCA connectors (and similarly XLR input connectors in a fully balanced system) on opposite sides of the amplifier rear panel and then running short wires to the amplifier modules. This arrangement is the worst of all worlds. The internal loop areas available […]

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So Just How Quiet is Your Phono Stage?

You may be in for a surprise: actually not that quiet! The reason of course is that the cartridge inductance and resistance dominate the noise in any decent phono amp. To get the best in terms of noise performance, you really need to keep the input referred noise voltage and noise current to a minimum. […]

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Fast Transimpedance aka Voltage Amplifier Stages for Audio Power Amplifiers

Here is a quick look at some of the problems that can occur when the VAS (aka TIS) in an audio amplifier is driven into saturation without considering the effects of base charge storage – a phenomenon all bipolar transistors suffer from.

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