Headphone amps.

Discussion in 'Home Theater Projects' started by Mark Fitzsimmons, Jun 21, 2003.

  1. Mark Fitzsimmons

    Mark Fitzsimmons Supporting Actor

    Aug 18, 2001
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    I just got my Sennheiser HD-280 Pro's yesterday for dorm and think it'll be best if I get a proper amp to drive them. Wondering if anyone has built a diy headphone amp before. They are 64 ohm headphones, so they don't need tons of power to get loud and I need an amp design that will be simple to make. Simplicity is key because many of the designs I've seen look awfully complex and I'll be a first time builder.

    Thanks in advance.
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Feb 1, 2002
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    I built a headphone amplifier using the LM386 integrated circuit. It uses a 9V rechargeable NIMH battery and has an AC Adapter plus green LED "on" indicator.

    It has enough power to amplify headphones to excruciating levels, as well as power high sensitivity small speakers. (to low volumes)

    Anyways, I basically researched designs from this site:


    This site shows how to make the headphone amp that I personally made. The only modification I made was adding dual outputs so 2 ppl can use the headphone amp and an LED.

    I bought most of my parts from partsexpress, with a few odd parts from Radioshack. I also used a larger project case than he did so I had more room to place the components.

    Expect total cost to be in the $40 range. My amp has a smooth frequency response, sounds just as good as the source with a barely audible "hiss". Once the music is playing you don't notice it anymore.

    Here are the specs:

    Size: 1 x 2 x 4 inches more-or-less
    Weight: 5 ounces (includes NiCd battery)
    Distortion: 0.2%
    Freq Response: 5Hz to >110kHz (-1dB)
    Max Output level: 1.7Vrms (loaded with RS Pro 25 phones)
    Noise: Inaudible in quiet room
    Output Power: 375mW into 8-ohms
    Input Impedance: 33Kohms, minimum
    Running Time: 6-hours, est, high-cap NiCd, depending on audio level
    Circuit Desc: Uses two LM386 power amp chips, 10-caps, 5-resistors.
    Controls: Volume, On/Off switch
    I/O's: Input pigtail, mini-phone out. DC power in.

    May I remind you that this was my first amplifier I ever built, but I had experience with soldering so it didn't take me longer than 4 hours or so. There was some trouble shooting towards the end that took up most of the time because I had some oscillating going on. The solution was I found out I didn't ground a component.

    Good luck
  3. Ellen

    Ellen Stunt Coordinator

    Jan 8, 2000
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    You might also check out the META42.

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