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Tag: feedback
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/…
RIAA Equalizer Amplifier Design
This article explores the fundamental’s of phono amplifier design, culminating in a few practical designs. Special emphasis is placed on overload margins (critical if you want good sonics from your EQ amp), driving the EQ network adequately and noise. RIAA Equalization Amplifiers V2.0 Below is the RIAA Calculator Excel spread sheet. Please read the article above,…
Ovation e-Amp: A 180 Watt Class AB VFA Featuring Ultra Low Distortion
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…
Audio Power Amplifier Design – Peter J Baxandall
In this 6 part series of articles published from January 1978 in the now defunct Wireless World magazine, Peter Baxandall takes the reader through some of the fundamentals of audio amplifier design as they were understood at the time. Baxandall_Audio Power Amplifier Design In 1978 there was still much discussion about feedback and how to…
Augmented Feedback Error Correction (AFEC)
AFEC is a simple technique that augments the feedback of an amplifier to dramatically improve the Large Signal Non-linearity (LSN) distortion performance by up to 20 dB across the audio band. Additionally, AFEC acts to remove any DC offsets and also improve PSRR significantly. Augmenting the feedback in a manner similar to that described in…
Output Coupling Inductors
Inductors on the output of an amplifer are used to isolate the amplifer from capacitive loads at HF and ensure stability. There has been quite some debate on DIYaudio.com as to whether they are audible, necessary, or just the result of designers being overly cautious. Some very well known designers in the field have decided against using…
Oscillation Sniffer
No ‘scope? This simple circuit can help you quickly see if you have any oscillation problems on your opamp or amplifer circuit. Note, its NOT designed to be connected to high impedance nodes. Oscillation Sniffer by Bonsai
H.S. Black: Feedback
Feedback, or its application by humans as control theory, despite the protestations of audio designers that eschew its use, is an entirely natural phenomena. Every time you reach out to pick up an object, get up and walk around, or write something on a piece of paper, feedback data from multiple body sensors are being…
Measuring TIM
This paper by Leinonen, Otala and Curl investigates the measurement of TIM, a hot topic in the 1970’s and early ’80’s after its potential to cause sonic degradation by the incorrect application of feedback around high loop gain solid state amplifiers. Now days (2017), there is a very complete and thoroughly in-depth understanding of TIM…