[tomb]

  Honestly, I just wanted to build an amp. They all cost about the same amount....
 
So what if I chose a 3 channel? Literally, so what? It still sounds good, right? There are still people who have built it and love it, right? If there are any issues or problems, I also am building the o2 amp...
 
If there are further and further issues, I now have MULTIPLE opamps I can use for future builds.

 
There's a very easy way to tell when you build one.  Simply temporarily short the output ground channel to chassis ground.  You can do this by simply connecting the headphone jack's ground to chassis ground. That will take the active ground channel out of the circuit.  The difference in the sound of the amp is night and day.  It's one of the things you must do when building one - be certain the output ground is isolated from the chassis ground for proper operation of the 3rd channel.
 
It's also a reason why many people don't know how to properly test one - you have to lift the ground on the measuring device, or else you're shorting out the active ground channel.  There's been a whole lot of mis-informed scuttlebutt spread around the internet as a result - and that's probably an understatement.
 
From Morsel's webpage on the PPA (the original active ground channel headphone amplifier):
"Signal ground is input ground, not output ground. Output ground is the output of the ground channel. It exists solely to drive headphones. It is not a true ground. Do not connect signal ground to output ground. This defeats the purpose of differential output and may cause amplifier instability. Do not use the headphone output as a line level output as this may short signal ground to output ground. Use signal ground instead of output ground for line level outputs."
http://elvencraft.com/ppa/
 
It's easy to see that without proper precautions, testing the output on an active ground channel amplifier can lead to horrible measurements if the instrument is connected in the "normal" way, as if the amplifier was a line-level device from the headphone jack.  
 
So yeah - build a 3-channel amplifier ... they definitely sound good.

 

 

[wakibaki]

So what if I chose a 3 channel? Literally, so what?

You might get a visit from the 2-channel police.

jcx makes some good points. You're not the only potential benefiter here. Other people are reading this thread.

The waste of money may seem of little consequence to you, had you but known you could have given it to charity, and got a better amp into the bargain. Have a look, the cost of a populated board can easily exceed the yearly income of a person in the 3rd. world.

Anything that can be done to mitigate the present effects of past mass hysteria is to be welcomed.

w

Re-reading this, I'm struck by the idea that hysteria is not very far below the surface at any time in this audience, after all, in most instances headphone amplifiers are redundant. I bet I could hypnotise a whole roomful of you guys with just a click of my fingers.

 

[tomb]

waki-hypnotism?
 
Of course jcx makes some good points.  He always does.  You didn't, though.  There's another side to the issue - always has been.  It's some people who try to slam the lid on that that make the offense.
 
Here's a question - have you ever built a 3-channel amp?  Compared it to the same version with two channels? Tried to tell the difference?  Shorted out the active ground and noticed the effects?
 
Just some questions while you're busy clicking those fingers.

 

[wakibaki]

tomb
 
It surprises me not at all to discover you, advocating that someone should waste their money.
 
Your behaviour is self-serving to the point of being embarrassing to witness.  You are a member of the trade, try to act like you understand financial propriety, even if you have no appreciation of design consideration.
 
w

 

[mcandmar]

You need to lay off the wakibaki mate, your making no sense..

 

[esiuda]

You are exactly right.  Build whatever YOU want,
 
Everyone's ears are different.  We may each like a slightly different sound.  I have friends who can not tell the difference between a 128 mp3 and a Flac of the same song.  Or the difference between some cheap bookshelf speaker system and some very decent expensive speakers, other then the big speakers are louder.
 
Build it, use it, enjoy it.  Do not be afraid to experiment.  Do not be afraid to fail.
 
Do not get hung up on the numbers game.  You could go crazy changing parts, and circuits to get the best test results, but does it sound good to you?  Remember, the only one you have to impress is yourself!
 
I have built the O2, which is a 2 channel amp.  I liked it
 
I then built AMB's portable, which is a 3 channel.  I liked that also.
 
Yes they sound different,  To me the AMB sounds a little better.
 
I then built the O2 power booster board from AGDR.  Seems to tighten up the O2 just a bit.
 
But guess what, I enjoy listening to both of them!  They both sound great!  I have always enjoyed putting together circuit boards.
 
I am currently getting parts for a B22 build, like I said before, I will start with 2 channels, 1 power supply, and then 2 channels 2 power supplies, then a 4 channel 1 power supply.  I have the option of stopping at any time!  Extra parts just go into another system I will put together for my kids to use. 

 

[VelictAF]

  tomb
 
It surprises me not at all to discover you, advocating that someone should waste their money.
 
Your behaviour is self-serving to the point of being embarrassing to witness.  You are a member of the trade, try to act like you understand financial propriety, even if you have no appreciation of design consideration.
 
w

 
 
It's my money. It's our hobby. You're the one person here who isn't benefiting head-fi almost at all.

 

[VelictAF]

  You are exactly right.  Build whatever YOU want,
 
Everyone's ears are different.  We may each like a slightly different sound.  I have friends who can not tell the difference between a 128 mp3 and a Flac of the same song.  Or the difference between some cheap bookshelf speaker system and some very decent expensive speakers, other then the big speakers are louder.
 
Build it, use it, enjoy it.  Do not be afraid to experiment.  Do not be afraid to fail.
 
Do not get hung up on the numbers game.  You could go crazy changing parts, and circuits to get the best test results, but does it sound good to you?  Remember, the only one you have to impress is yourself!
 
I have built the O2, which is a 2 channel amp.  I liked it
 
I then built AMB's portable, which is a 3 channel.  I liked that also.
 
Yes they sound different,  To me the AMB sounds a little better.
 
I then built the O2 power booster board from AGDR.  Seems to tighten up the O2 just a bit.
 
But guess what, I enjoy listening to both of them!  They both sound great!  I have always enjoyed putting together circuit boards.
 
I am currently getting parts for a B22 build, like I said before, I will start with 2 channels, 1 power supply, and then 2 channels 2 power supplies, then a 4 channel 1 power supply.  I have the option of stopping at any time!  Extra parts just go into another system I will put together for my kids to use. 

That's what I'm talkin' bout bro. I'm all about breaking and experimenting. that's a true hobbyist. Not someone who says "this is bad, because I think it's bad. End argument"
 
Edit: Here are some 18 gauge wires I twisted and made! I have 22 gauge, too. Pictures incoming.