Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

The Zen Headphone Amplifier

The Zen Headphone Amplifier

Excellent sound quality, simplicity, linearity and no multi-stage feedback. It is a single stage class A MOSFET design with the right gain and a low output impedance.
The schematic in figure 1 shows one channel of the headphone amp. The HexFets employed are the usual International Rectifier IRF610, both for the active side and for the current source. The circuit is quite simple, only one gain stage built around an IRF610 (Q2 at the bottom of the schematic), biased by another IRF610 (Q1). The two diodes (D1 and D2) are for over-voltage protection purposes: any type, between few volts and about 15-16V will work fine.

The main idea behind Pass’ variable current source is that the bias current is controlled by the output signal. The “sensing amplifier” is built around Q3. An output resistor, R11, senses the current through the load. Q3 drives the gate of Q1 and modulates the bias current in Q2 according to the “sensed” load current.

The Grados are low impedance headphones, about 30 ohms, and are very efficient too. To get the maximum output swing required by a headphone amplifier, I measured, by a storage scope, the maximum output level at which the headphones began obviously to distort. At 2.7Vpeak (1.9Vrms), there was enormous sound pressure from the headphones. This was definitely plentiful!

Visit Here for more.

 

More Articles to Read

A 400W (1kW Peak) 100A electronic load using linear MOSFETs
A 400W (1kW Peak) 100A electronic load using linear MOSFETs
Shirt Pocket Transceiver with the Si5351 and OLED
Shirt Pocket Transceiver with the Si5351 and OLED
All metal C930e webcam
All metal C930e webcam
The Soldering Tools That Make Your Life Easier
The Soldering Tools That Make Your Life Easier
App note: Operation evaluation of ultra low ON resistance MOSFET supporting quick charge for 1 c ...
App note: Operation evaluation of ultra low ON resistance MOSFET supporting quick charge for 1 cell Lithium ion battery protection
Synthesized Sidetone
Synthesized Sidetone
App note: Application precautions: Power MOSFET application notes
App note: Application precautions: Power MOSFET application notes
A high current power supply built around a server voltage regulator
A high current power supply built around a server voltage regulator
Bridge Monitoring System using Wireless Sensor Network
Bridge Monitoring System using Wireless Sensor Network
Piezoelectric Micropump Driver
Piezoelectric Micropump Driver

Top




Shares