The Objective2 (O2) Headphone Amp DIY Project - Page 341 - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

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
Reply
 
Thread Tools Search this Thread
Old 28th August 2013, 04:22 PM   #3401
diyAudio Member
 
Join Date: Feb 2008
Quote:
Originally Posted by Zigis View Post
Probably too high gain.
Thank you for the suggestion Zigis, but, unlikely, switching the gain from 6.5 to 2.5 the distorion is still there (on the Cmoy I only have the default gain 9).


Northernsky
  Reply With Quote
Old 28th August 2013, 05:29 PM   #3402
agdr is offline agdr  United States
diyAudio Member
 
agdr's Avatar
 
Join Date: Sep 2010
Quote:
Originally Posted by ericj View Post
Is anyone currently selling nonmetallic faceplates?
Walter at Head N HiFi lists bamboo, acrylic and even leather in his pull-down list:

O2 Front Panel
  Reply With Quote
Old 28th August 2013, 05:32 PM   #3403
agdr is offline agdr  United States
diyAudio Member
 
agdr's Avatar
 
Join Date: Sep 2010
Quote:
Originally Posted by northernsky View Post
I was surprised because I can clearly recognize an audible distortion by the O2 amp, especially audible on music with high power on bass.
What DC offset voltage do you measure on the output of each channel with nothing plugged into the input jack? Should be around 3mV or so.

If the offset voltage looks OK one thing to try would be new output NJM4556A chips, however they are not likely to both be bad. Is the amount of distortion about equal on both channels? Also take a DC voltage reading from the metal shell of the gain switch (ground) to pin 4 of either NJM4556, then again from ground to pin 8 and see what you get (the power supply rails).

Last edited by agdr; 28th August 2013 at 05:39 PM.
  Reply With Quote
Old 28th August 2013, 07:49 PM   #3404
diyAudio Member
 
Join Date: Feb 2008
Quote:
Originally Posted by agdr View Post
What DC offset voltage do you measure on the output of each channel with nothing plugged into the input jack? Should be around 3mV or so...
Thank you agdr: you gave me my job for the weekend...

Northernsky
  Reply With Quote
Old 28th August 2013, 09:18 PM   #3405
JZatopa is offline JZatopa  United States
diyAudio Member
 
Join Date: May 2003
Location: Chicago
Interested in a 3d printed one?
  Reply With Quote
Old 28th August 2013, 09:31 PM   #3406
agdr is offline agdr  United States
diyAudio Member
 
agdr's Avatar
 
Join Date: Sep 2010
Quote:
Originally Posted by DJNUBZ View Post
Interested in a 3d printed one?
Hey that is pretty slick! Just curious - can you make 2mm thick, same as the aluminum panel?
  Reply With Quote
Old 29th August 2013, 07:45 PM   #3407
JZatopa is offline JZatopa  United States
diyAudio Member
 
Join Date: May 2003
Location: Chicago
Here is a design someone has already created.

I am waiting for some parts for my printer and then I can print one for you. Let me do a test print and see what I get when I can.
  Reply With Quote
Old 29th August 2013, 08:35 PM   #3408
agdr is offline agdr  United States
diyAudio Member
 
agdr's Avatar
 
Join Date: Sep 2010
Wow, you've been able to print the whole case! That is fantastic. I haven't messed with 3D printers at all. I'm sending a PM. One of the reasons I gave up on this project

An "O3" - 35% smaller SMD RS O2 headphone amp version

was the case from Hammond was about 3/4" too short to use PCB mounted battery snaps instead of snaps on leads. Looks like your printer could kick out custom case sizes!

Last edited by agdr; 29th August 2013 at 08:39 PM.
  Reply With Quote
Old 29th August 2013, 09:52 PM   #3409
diyAudio Member
 
Join Date: May 2013
Just thought I'd mention that Shapeways - Make, buy, and sell products with 3D Printing is a great place to have your 3d designs printed. Just take a look at their material selection list:
3D Printing Materials on Shapeways

mmm, stainless!
  Reply With Quote
Old 30th August 2013, 08:13 AM   #3410
diyAudio Member
 
availlyrics's Avatar
 
Join Date: May 2011
Quote:
Originally Posted by northernsky View Post
Thank you for the suggestion Zigis, but, unlikely, switching the gain from 6.5 to 2.5 the distorion is still there (on the Cmoy I only have the default gain 9).


Northernsky
Assuming you are using DIP8 OPA2134 or so you can chk.-
each JRC4556 from O2 in your CMOY at low gain (2X and NOT 9X).
or/and
use the opamp in CMOY in the gain stage of O2.
Swap opamps one by one, listening to any audible distortion. Beware of offset voltages at o/p(not above 20mV) & use only elcheapos h/p for initial testing.
__________________
Thanks,
availlyrics
  Reply With Quote

Reply


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
Headphone amp project grahamfocal Headphone Systems 7 21st June 2011 05:28 PM
My latest project - DAC + headphone amp gmarsh Digital Line Level 105 13th December 2010 02:31 PM
My headphone amp project trifidmaster Headphone Systems 2 22nd December 2008 03:52 PM
Mini Ipod headphone amp DIY project Nordic Headphone Systems 14 11th March 2007 02:35 PM
Need help for a battery headphone amp project dismalonyx Headphone Systems 1 15th April 2004 11:22 PM


New To Site? Need Help?

All times are GMT. The time now is 11:08 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2