|
A Current-Domain Electrostatic Amplifier for Stax Omega II Headphones - The amplifier
operates primarily in the current domain. The first stage is a voltage controlled current sink. The second stage is a current-controlled voltage source. The fourth stage is a constant current sink. The main advantage of current domain amplifiers is speed..... designed by
Kevin Gilmore (circuit design added 04/05/06) |
|
A DC-Coupled Tube Amplifier With Futterman Output Stage for Dynamic Headphones - The
Futterman output stage in this tube amp offers the choice of DC- and AC-coupled outputs. The class AB design can output up to 24mW into a 30-Ohm load or nearly 500mW into a 600-Ohm load. Designed by Rudy van Stratum (circuit design added 04/05/06) |
|
A Digitally Programmable Gain and Attenuation Amplifier Design - AN-137 Analog Devices
Application Notes (app note added 2/06) |
|
A Fender-Tone Tube Headphone Amplifier - This tube amplifier with sonic controls has a
paralleled White cathode follower output stage for driving low impedance headphones. The sonic controls consist of a Fender tone stack (bass, mid and treble), and ambience and blend controls. Includes simulation files for use with OrCAD Lite software. Designed by
Alex Cavalli (circuit design added 04/05/06) |
|
A HiFi Preamp - The PGA2310 is a pretty neat chip. It's capable of attenuating a stereo source over a 127dB range (-95.5dB to
+31.5dB) with 0.5dB steps. It has a maximum gain error of +/-0.05dB, and THD of 0.0004% at 1KHz. The sweet spot between THD and noise appears to be between 3V RMS and about 8V RMS...(circuit added 04/05/06) |
|
A JFET-MOSFET Headphone Driver - This amplifier is based on the MOSFET headphone driver by
Greg Szekeres. It has a JFET impedance buffer front-end and a choke-input power supply. The sound characteristic of the amplifier can be tuned by adjusting the low pass filter formed with the input capacitance of the MOSFET. Designed by Richard Murdey (circuit
design added 04/05/06) |
|
A Low-Voltage Class-A Tube Headphone Amplifier - This OTL design features a high-voltage
power supply that is less than half of the one used in the author's first amp and most other tube amps, but without compromising performance. Designed by Helmut Ahammer (circuit design added 04/05/06) |
|
A Musical Distortion Primer - This is an introduction to the basic means of distorting a signal in a musically
useful way. The approach is as non-technical as possible. I use the simplest signal waveform, a sine wave, to illustrate all these, although a guitar is much more like a sawtooth than a sine wave. The clipped waveforms will be shown in their raw state....(circuit
design added 04/05/06) |
|
A Non-Complementary Audio Noise Reduction System - National Semiconductor Application Note (app note added 2/06) |
|
A Pocket Headphone Amplifier - This is a Chu Moy headphone amp I made. I got the PCB design
from Guzzler from Head-Fi and the original design is very popular and is here. I changed Guzzler's layout so I could use a Taiwan Alpha pot on the PCB. These pots a high quality (some say better than ALPS blue velvet) and are available from Jaycar. You can see the thread
here. I also made a DIY Brown dog adapter so I could use two OPA627 single opamps in a dual opamp socket. |
|
A Pure Class A Dynamic Headphone Amplifier - A high-current output amplifier for
low-impedance dynamic headphones such as the Grados. The amplifier features an new servo biasing circuit which operates entirely outside the audio feedback loop. The author includes a balanced-bridge version of the amp for headphones that are wired in dual-mono as well as
instructions for converting a Grado SR80 to dual-mono operation.... Designed by Kevin Gilmore (circuit design added 04/05/06) |
|
A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers - A basic circuit is provided in the article,
but it is assumed that the builder knows all the pitfalls. The supplied schematic is in fact for a capacitance multiplier filter (not a regulator), but is somewhat lacking (I feel) and can be improved dramatically....(added 04/05/06) |
|
A Single-Ended OTL Amplifier for Dynamic Headphones - A simple OTL design that uses just
two tubes (dual triodes) for stereo. It has a common cathode input stage direct-coupled to a cathode follower output stage. Designed by Aren van Waarde (circuit design added 04/05/06) |
|
A SRPP-Input Tube Amplifier For Headphones And Loudspeakers - This transformer-coupled
design uses a series regulated push-pull input stage and a parallel-triode cathode bias output stage. The audio output transformer is hand-wound from a kit. The amp will drive both headphones and speakers. Designed by Tony Frazer (circuit design added
04/05/06) |
|
A Tube Headphone Amplifier/Preamp with Relay-Based Input and Power Switching - A tube
headphone amplifier inspired by the "Top-Level" and "No-Compromise" amps of Andrea Ciuffoli, except that the output stage uses a triode-connected pentode. Because this amp also serves as a preamp, the author has put in a sophisticated relay-based switching system (both
input source selection and power supply). The power supplies also feature slow-on and stepped delayed turn-on. The power-on LED doubles as a warm-up status indicator. Designed by Helmut Ahammer (circuit design added 04/05/06) |
|
A Weighting Filter for Audio Measurements - For noise measurements. Ideal for use with the AC Millivoltmeter
above (electronic circuit added 4/05) |
|
A Zero-Feedback SRPP-Input Headphone Amplifier - Features a series regulated push-pull
input stage and transformer-coupled output stage with an output impedance of about 2.5 ohms. It has zero global feedback for open, natural sound without any harshness. Designed by Simon Busbridge (circuit design added 04/05/06) |
|
|
