Portable Headphone Amplifier(Premium Edition 2.5a)
Wednesday, July 11, 2012
Tuesday, May 1, 2012
The Objective2 (O2) is an open source headphone amplifier designed by Nwavguy, with emphasis on benchmark, performance and low cost. Comes fully assembled with custom front plates O2 amplifier and a UK/SG power adapter.
· Alps Dual Analog Potentiometer
· 3.5mm Input and Output Jacks
· Dual Gain Switch (2.5x and 6.5x)
· Opamps: JRC NJM2068D (Gain), 2x JRC NJM4556AD (Buffer)
· AC Jack
· Supports 9V Rechargeable NiMH Batteries for portability use. (Not Included)
· Custom 2 piece assembly front plates.
· CNC Aluminum base piece sand blasted finishing, clear anodized coated.
· Customized acrylic front piece.
· Flush Aluminum Knobs with rubber grips.
· Frequency Response: +/- 0.01dB (20Hz-20kHz)
· Gain: 2.5x and 6.5x
· Output Impedance: > 1 ohm
· Case Dimensions: 108.50 x 80.00 29.50 x mm (excludes knobs/buttons)
· Weight: Aprox 300g, with batteries
· 2 stage Opamp design
· Fully Assembled O2 Headphone Amplifier with Custom Front Plates. (Rev 1.1 - Nov 30th 2011)
· 240V AC to 15VAC 500mA UK/SG 3 Pin Power Adaptor Included.
Sunday, December 18, 2011
• Updated Custom printed Madcap Audio PCB Ver 2.2
• 2 stage opamp design.
• BB 2xOPA2227 Opamp in a Gold-Plated DIP Socket.
• Alps RK097 Volume Control with built in ON/OFF switch
• DC Power/Charging Jack
• Penguin Peppermint enclosure
• Dimension: Aprox size with knob:(6.2 x 11.3 x 2.4 cm)
2 Stage Opamp Design
The Madcap Audio amp features a two stage opamp approach that improves current handling. There are four opamps in the design: Two for the left ear and two for the right.
With improved current handling, it could drive headphones and IEMs that have relatively low impedance properly. This can improve the sound quality rather than the volume. As low impedance headphones/earphones requires more current to drive them properly.
Its a very stable opamp that gives user a warm and punchy sound with a wide sound stage.
The opamp is mounted in a gold-plated 8-pin DIP socket, allowing you to purchase other chips to alter the amp's "signature." Amplifier stability is an important concern when trying alternative opamps. A DIP socket gives you the option to try different opamps aka (Opamp rolling).
The quality of an amplifier's capacitors, resistors, and amplification chips plays a significant role in accurate sound reproduction.
- - - High quality Wima caps (input filtering caps)
- P - Nichicon E-cap (rail splitter)
- + - +/ - 1% ¼ watt resistors
New Printed Circuit Board
Most Cmoy amplifiers are built on perfboard and use thin wires to transfer the audio an electrical signals.
Madcap Audio amp is built on a high-quality printed PCB board. Which prove to be consistence and reliable when in operation.
Added decoupling capacitor/unity gain design in the PCB for more stable op-amp operation. (Needed for certain opamps)
The New PCB features improved grounding and circuitry routing.
The Madcap Audio Amp features the very popular Alps RK097 potentiometer, paired with a very high quality brushed aluminum knob.
Unit can be powered by a standard PP3 9v battery.
The Madcap Audio amp uses A standard resistor divider power system, with a pair of low ESR Nichicon 1000 uF capacitors. This will allow users to use higher current rated opamps without much limitation of current supply on ground.
DC Power / Charging Jack
Any linear-regulated 12V DC power adapter with a 2.1mm plug can be used to power the Madcap Audio Amplifier. Plugging in a DC power supply in “on” position will power up the device in playback mode. Plugging in a DC power supply in “off” position set the device in trickle charging mode.
(While using the charging mode, make sure only uses a PP3 9v NiMh battery !)
The Madcap Audio Amp is cased inside of very attractive * Penguin Peppermint tin. The metal casing also acts as a protecting the circuit from some forms of external EMI / RF interference. Foam support keeps the battery securely in place.
*Despite each tin being brand new, penguin peppermint tins occasionally have some sort of scratch or dent (not always!). Additionally, you should anticipate minor jack mounting imperfections due to the hand built nature of the product. Please excuse these possible minor cosmetic defects. Thank you!
• New Madcap Audio Headphone Amplifier
• Quick Instructions Sheet
Wednesday, October 19, 2011
Monday, May 2, 2011
Portable Headphone Amplifier