Using the QuantAsylum QA401 for accurate Audio Measurements
in Power amplifiers, Preamplifiers, Technical
The QA 401 from QuantAsylum (superseded by a newer, improved QA 402 and now the QA403) has emerged as a popular, comprehensive audio test instrument in the DIY audio fraternity and the go to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 […]
Building Quiet Audio Power Amplifiers Requires Best Wiring and Layout Practices
in Power amplifiers, Technical
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 […]
Fast transimpedance aka Voltage Amplifier Stages for Audio Power Amplifiers
in Power amplifiers, Technical
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 phenomena all bipolar transistor suffer from.
How to wire-up a Dual Mono Bloc Amplifier
in Power amplifiers, Technical
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 […]
JLH 10 Watt Class A Amplifier
in Power amplifiers, Technical
This is a copy of the original John Linsley-Hood article that appeared in Wireless World in 1969. This design, almost 50 years old, is still built in its hundreds all over the world. A quick root around on the web will show numerous kits, many of quite acceptable quality, emanating from China and Hong Kong. […]
Ovation e-Amp: A 180 Watt Class AB VFA Featuring Ultra Low Distortion
in Power amplifiers
The e-Amp is a 180 Watt RMS (very conservatively rated into 8 Ω ) fully balanced symmetrical (‘FBS’) amplifier featuring an emitter follower triple (EFT) bipolar output stage and beta enhanced VAS stage. The amplifier can be configured using jumpers for TMC (Transitional Miller Compensation) or straight Miller compensation (MC). The VAS can be lightly […]