The Objective2 (O2) Headphone Amp DIY Project - Page 195 - diyAudio
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Old 27th January 2012, 06:51 PM   #1941
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Thanks. I actually did have that saved somewhere.
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Old 27th January 2012, 09:26 PM   #1942
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Quote:
Originally Posted by Jelle Schrijver View Post
That ODA(C) must be very good. Has been a long time since we heard from RS. To busy listening I guess.

Here a nice comment on headfonia about the O2:

I lifted this comment from his blog's Winter Solstice post. It's dated Jan 24th.

--
There hasn't been much ODA/ODAC progress to report and it's purely because I haven't had as much time as I hoped to devote to the project. I also haven't been keeping up with the diyAudio and other threads. But hopefully I'll have more free time soon.
--
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Old 27th January 2012, 10:17 PM   #1943
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Quote:
Originally Posted by imminentdomain View Post
If you don't trust your ears, I think you're missing the point of listening in the first place.
I trust my ears to make it possible for me to enjoy listening to music by ignoring or compensating for minor (and even major) flaws in a reproductive system.

The point of listening is to enjoy the music, not to focus on the quality of the system it's played on.
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Old 28th January 2012, 01:07 AM   #1944
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I'm putting together my O2, and have a couple of quick questions...

What's up with all those gain resistors? - (it doesn't matter much, just like to know why so many?)

I guess P1 & P2 are test points on the pcboard.

I've got a pair of tenergy 9v batteries for the O2 - the O2 will keep these charged as long as the walwart is plugged in? Or can I run the O2 from the walwart (and not install the batteries)?
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Old 28th January 2012, 02:24 AM   #1945
Davey is offline Davey  United States
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It's a standard non-inverting op-amp gain stage. Gains greater than unity require two resistors to implement. The O2 has a two position selectable gain so the requirement for the third resistor. It 'can't' be any simpler than that.

http://en.wikipedia.org/wiki/Op-amp_...ting_amplifier

The O2 charges installed batteries with the wallwart plugged in with power switch on or off. But you can easily run it sans batteries.

All of this operational stuff is explained in the extensive excellent documentation RocketScientest has provided for the O2.

Cheers,

Dave.

Last edited by Davey; 28th January 2012 at 02:27 AM.
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Old 28th January 2012, 02:27 AM   #1946
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thanks. i got all these extra resistors. i forget what i installed, but i guess if i don't have enough gain for my phones i can swap out those resistors.
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Old 28th January 2012, 01:57 PM   #1947
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Almost done. Why are there like 12 holes for the pot? Do I use the ones closes to the edge of the board?
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Old 28th January 2012, 02:27 PM   #1948
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NwAvGuy: O2 Details

Look about 1/4 of the way down under Component Notes. It tells you which holes to use as well as other things to do while soldering the board. If you used the 15mm from the BOM, you use the 6 holes closest to the board. I think on that piece, you have to clip off that metal edge as well or it will touch the front of the case.
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Old 28th January 2012, 02:31 PM   #1949
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yes, i found a photo for reference.

I've got it powered it up! Unfortunately, I don't have a pair of cheap headphones and an audio source to test it with yet.
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Old 28th January 2012, 03:34 PM   #1950
jmwreck is offline jmwreck  Philippines
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Click the image to open in full size.
Click the image to open in full size.

just wanted to show the outcome

hope its ok to post pics
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