A JFET preamp for beginners. Simple yet elegant. Low noise.
The following is an example for a very simple and high quality JFET preamp. You can use this to amplify a very low signal sources. FET transistors are usually not used independently in preamplifiers. In most of the cases they are paired with bipolar transistors. Read More »
We have completed this module this week. It is a custom build by order of a customer. The module has many specific functions. It can be used for speaker protection, speaker delay, toroid soft start and others. Read More »
Well we all like and enjoy beautiful things of life. Art is a fine example. Engineers however are a kind of different animals. They enjoy looking at bizarre things. I do as well. What you see on the right is a fine example. A “painting” made out of electronic elements. Almost every possible type of electronic device is used and I think it’s amazing.
No deep thoughts about this. I’m not an art expert. Some might find it ugly, some might find it strange or whatever. I just wanted to share this with everybody.
If you like this be sure to check out this website.
Define Original and Reproduced musical and audio contents
In general we listen to musical performances in two basic ways. The first one involves an actual attending to real live music events (a concert, an opera, ballet music festival etc.). In this case the musical content we perceive is called ORIGINAL musical (audio) content (OAC), unlike the REPRODUCED musical (audio) content (RAC), which we perceive by using electronic and electro-acoustic devices. For the purpose of this article I will use the terms original audio content and reproduced audio content.
The reproduced musical contents are generally divided by two groups depending on the time we listen to them.
The first type is the so called synchronous audio contents. Those we get when we listen to any LIVE broadcasting over the TV, radio and live internet streams. This type of musical content is characterized by the fact that it occurs simultaneously with its original prototype but at a different place.Read More »
So it was a pleasant weekend. Just a few folks gathered together to listen to some good music. Well not only. It’s always about listening to something in particular and test it against something else. In this case one of the guys had brought his beloved CD player – the Unico CD Primo by Unison Research.
Well I had to say that I was rather suspicious about this testing. The first thing is that this CD player has a really good looking tube output stage. Having noticed that it was clear that this fellow has nothing to do with the neutral and transparent sound. However I kept my thoughts to me and we all sat down and listened. Read More »
Here is a very interesting video on how to test power supplies. There are four parts actually. The series of videos focus on using DC-DC buck and step-up power supplies by Texas Instruments. The techniques described however are applicable to any other manufacturer.
The first part shows some power supply testing fundamentals like setup overview, necessary equipment, proper connections etc.
Here is a very good schematic showing a tipical power amplifier grounding system. I have tried it ina many of my projects and it works every time. No hum, no ground loops no noise. Dead silent. Of course a proper power supply routing on the main PCB is critical. If done properly some very very high performance could be achieved.
One of the more troubling aspects of analog circuit design is amplifiers that oscillate when they are not supposed to. Engineers commonly respond to spurious oscillations with empirical efforts to defeat the instability, by throwing small-value resistors, ferrite beads, and bypass capacitors at the problem (whether in a hardware prototype or circuit simulation), hoping it will go away. Perhaps these kludged circuits stop oscillating, but then the performance has been degraded. Or perhaps occasional production units oscillate. What is a circuit designer to do?
The answer, of course, is to understand why the circuit oscillates. There is always a rational, underlying cause for annoyingly unwanted sinusoids, and finding it can lead not only to a stable circuit, but also a performance-optimized circuit. Not only can the oscillation be modeled and its compensation designed, the margin of stability can also be estimated so that you can know how far from oscillation the circuit design is.
In Part 1 we examine causes and solutions for discrete BJT (bipolar junction transistor) amplifier circuit oscillation. The principles carry over to FETs fairly directly. We will look at two cases: in the first parasitic resonance is the cause; in the second the little-known effect of high-frequency impedance gyration explains why capacitively-loaded emitter followers often oscillate.
Why Circuits Oscillate Spuriously, Part 1: BJT Circuits by Dennis L Feucht – >>>LINK<<<
In the January issue the concept, and possible consequences, of slew-rate limitation were discussed, with particular reference to one cause, in which the first stage of an amplifier is unable to supply the current demanded by the collector-to-base feedback-stabilization capacitor in the second stage. With suitably modified circuit designs such effects may be made insignificant. Before specific circuits are discussed in later articles, the present article will deal with some basic ideas about negative feedback and transfer functions.
This one is an interesting article by AES, featuring considerations about the interface, jitter and other interesting topics.
In a correctly functioning digital audio system the only observable signal impairments should be attributable to band-limitation and an additive noise residue. Thus although the subjective sound quality of digital audio has received some criticism since the launch of the compact disk (CD) medium 10 years ago, there can be little doubt that the theoretical performance obtainable from the 16 bit linear PCM format sampled at 44.1 kHz is superb compared to any analog source available to the customer
Is the AES/EBU / SPDIF Digital Audio Interface Flawed? – >>>LINK<<<
This issue includes:Paper: The Mathematics of MixingPaper: Modeling and Analyzing Resonant Panel AbsorbersPaper: Forensic Evaluation of Electrical Mains Frequency AnalysisEngineering Report: Testing the Preference Consequences of Dynamic Range CompressionEngineering Report: Long Term Trends of Dynamic Processing in Mainstream MusicFeature: Recording Preserva […]
This issue includes:Paper: Unified Speech and Audio Coding Standard for Varied Content and Bit RatesPaper: Panning Phantom Images Using Time and Level DifferencesPaper: Frontal Projection Headphones for Improved Spatial AccuracyPaper: Vertical Localization in a 3-D Wave Field SynthesisPaper: Acoustic Feedback Control with Adaptive EqualizerEngineering Report […]
This issue includes:Paper: MP3 Compression Can Change Timbre of Sustained Musical TonesPaper: Interaural Intensity Differences from Real and Phantom SourcesPaper: Exploring Sensitivity to Changes in Phase SpectrumPaper: A Robust Audio Watermarking SystemPaper: A Dual-Channel Speech Reinforcement System for VehiclesEngineering Report: Noise in Audio TriodesEn […]
This issue includes:Paper: Automating Dynamic Range Compression Parameter ValuesPaper: Multiport Acoustic Models for Audio Signal ProcessingPaper: Physical Modeling of Timpani Drums with Graphical Processing UnitsPaper: Evaluating Hearing Damage from Portable Listening DevicesPaper: Examining the Audio Quality of Digital Broadcast SystemsPaper: Frequency Dep […]
This issue includes:Paper: Wavetable and Sampling Synthesis Using Higher-Order IntegrationPaper: Minimizing Decorrelator Artifacts in Directional Audio CodingPaper: Measuring Impulse Response with a Constant Signal-to-Noise RatioPaper: Using Ultrasound to Create a Virtual MicrophonePaper: Workplace Noise Regulation in the Music IndustryPaper: Speech Intellig […]