High power headphone amp - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Headphone Systems Everything to do with Headphones

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 1st February 2013, 07:44 AM   #1
diyAudio Member
Join Date: Sep 2012
Default High power headphone amp

A while ago I made a pcb for a high power headphone amp that can drive all impedances. It is a simple design with an opamp followed by a pair of diode biassed BD139/140 or BC327/337 for more current. The PCB has been used by several people and it works really well for a low price. Total price is 20-25 euro without housing.
Attached Images
File Type: jpg DSC_0194.jpg (621.9 KB, 248 views)
File Type: jpg schematics.jpg (113.7 KB, 245 views)
  Reply With Quote
Old 1st February 2013, 07:49 AM   #2
diyAudio Member
Join Date: Sep 2012
A new version is almost done. It will be ordered soon.
It now has a transformer on the PCB as well.

It fits in standard housings for 100x160mm PCBs, leaving room for potmeter, connectors etc. See attachment for an example of the case someone made with my PCB inside I think it looks really nice.
Attached Images
File Type: jpg DSC_0195.JPG (80.2 KB, 231 views)
File Type: jpg headphone_amp_2_2.JPG (568.6 KB, 198 views)
  Reply With Quote
Old 1st February 2013, 09:18 AM   #3
jcx is online now jcx  United States
diyAudio Member
Join Date: Feb 2003
Location: ..
gnd is connected "wrong way around" - the xfmr ct to rectifier/cap gnd is a "dirty gnd" large 2x line frequency charging current pulses flow in it, the amp circuitry should connect to the regulator side of the reservoir C gnd, let the xfmr ct trace be a stub

the outline suggests an EI xfmr - may radiate mag field causing hum so close to the amp circuitry, traces - if it has a "belly band" you may want to rotate 90 - or allow room for some iron/low carbon steel sheet shielding

for added stability I would add a inner feedback C to each op amp that could be a stuffing option

local nF bypass caps at the op amp should be connected right at the op amp ps pins, choose one size - the "universal" hole pattern adds inductance - I would use different circuit rather than rework part values

but probably little need for the 22 uF C11/20 so close to the reg

the pull-up/down R for the Vbias may be too high for the worst case range of output Q hfe, may limit current at high Vswing, low frequency

Last edited by jcx; 1st February 2013 at 09:24 AM.
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
HPA-2 Headphone Amp Kit (High quality & High-end components) kawo Group Buys 20 17th February 2012 04:34 PM
High Quality headphone amp shark70 Chip Amps 1 16th March 2010 01:38 PM
High linearty low-power BJTs and Class A headphone amp percy Headphone Systems 24 27th July 2009 05:00 PM

New To Site? Need Help?

All times are GMT. The time now is 06:21 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2