[chrislangley4253]

enjoyed reading your impressions OP

 

[adydula]

Hello to All...
 
Sitting here listening to Blood Sweat and Tears.....with the O2 and ODAC.
 
After going thru several amps, SOHA ii DIY, Schitt Asgard, Schitt Lyr and a multitude of tubes, A few AVR's and a Preamp head section..
 
Bought on3 O2 from JDS Labs and liked to so much I built a second one...parts arent that bad at all to get from Mouser.
 
Board from JDS.
 
Using with Q701's, LCD2's and Grado 325i's...no real issues driving any on these and all sound very good in their own right.
 
Also bought several AC to AC supplies to play with voltages and gain settings...
 
Running stock settings with these cans and again no issues driving.
 
Highly recommend this amp as a first DIY project....hard to go wrong.
 
All the best
Alex
 
PS: All the other amps are out of the inventory.

 

[adydula]

gates_2....
 
How are u liking the O2 ??
 
Still ok fine?
 
Alex

 

[gambit300]

Okay, I feel like an idiot posting this, but I have run out of ideas. I put an O2 together, but apparently I had a few of the diodes in backwards. I blew a capacitor. I went ahead and replaced the cap and fixed the diodes. I doubled checked to make sure that everything was in correctly. I turn on my O2 and the LED lights up and nothing blows up (yay). When I plug in headphones and my source, I have to turn both my source and O2 volume up all the way before I can hear anything. The sound is only barely audible when I do this. I literally have to be in a quiet room and concentrate to hear the music. Any ideas how I can go about trying to figure out what is wrong?

 

[adydula]

gambit there is a troubleshooting section on the designers site....
 
Check each and every component you installed and make sure they are the correct values in the correct place on the board. You should have measured all the resistors for their values before soldering to the board....check all the voltage and resistance checks per the instructions on the site.
 
Sounds like you have  an amplification problem, if you have to crank up the volume to hear anything....check to make sure the gain resistors are the correct values and in the correct places on the board.
 
Make sure your op amps are in the ic sockets are the right ones and in the right way.
 
It also could be a short across the "lands" as we call them or "traces" carefully check.
 
Take your time and look for solder bridges and cold solder joints...
 
Alex

 

[gates_2]

Well, I was enjoying my O2, I gave it to a friend, but he said he couldn't get it to work.
 
Cue frustration.
 
On further review one of the 9V batteries looks somewhat deformed. Not sure if it was an internal battery issue or an amp-charging issue.
 
The amp lights up when plugged in, but no sound whatsoever. I thought it must be the MOSFET's. Replaced those, no dice. Only reading 12V between the battery terminals with an 18V AC supply line.
 
Replaced U5, U6, and all the op-amps on the board. No dice, powers on but no sound what-so-ever.
 
Reworked every solder circuit on the board. No dice.
 
Frustrated. I've never had an amp give me so much headache, and I've built numerous, much more complicated ones!
 
Anyone with a similar situation/Advice? I'm getting close to just throwing this away. No problem for months and months, and then it dies.

 

[fihidelity]

Quote:

Well, I was enjoying my O2, I gave it to a friend, but he said he couldn't get it to work.
 
Cue frustration.
 
On further review one of the 9V batteries looks somewhat deformed. Not sure if it was an internal battery issue or an amp-charging issue.
 
The amp lights up when plugged in, but no sound whatsoever. I thought it must be the MOSFET's. Replaced those, no dice. Only reading 12V between the battery terminals with an 18V AC supply line.
 
Replaced U5, U6, and all the op-amps on the board. No dice, powers on but no sound what-so-ever.
 
Reworked every solder circuit on the board. No dice.
 
Frustrated. I've never had an amp give me so much headache, and I've built numerous, much more complicated ones!
 
Anyone with a similar situation/Advice? I'm getting close to just throwing this away. No problem for months and months, and then it dies.

Perhaps the battery heated up to the point that it damaged the PCB, it sounds unlikely but it seems like you've checked most all else.

 

[gates_2]

Yea who knows, fed up and scrapping it on the sale forums for parts.
 

 

[tomb]

Quote:

Yea who knows, fed up and scrapping it on the sale forums for parts.
 

What about sending it to NWAVGUY?  From reading his blog on the O2 and all of his claims, seems like he might be able to fix it.  At the very least, one would think he would respond to some pics and a question for help.

 

[fihidelity]

What about sending it to NWAVGUY?  From reading his blog on the O2 and all of his claims, seems like he might be able to fix it.  At the very least, one would think he would respond to some pics and a question for help.

Unfortunately he's basically disappeared from the face of the Eart. Worth a try though.

 

[HolyCheese]

I have built this amp (just started the third) and I must say that i'm very impressed. It's certainly much MUCH!!!!! better then my e10. Great thing for it's price. 
I didn't know what to expect after all the negativity but I actually wowed when I first listened to it.
 
I don't own any high end amplifiers and maybe I can do an comparison sometimes but my next goal is a new DAC. No need for an amp. Though I probably will build some just for fun. Anyone got a nice tube amp recommendation? I'm actually pretty good at DIYing but still a beginner. So I guess you could say I'm average good at it.

 

[adydula]

Yes he has disappered from the scene but it doesnt take anything away from his designe and the many hundreds of O2 amps that are out there functioning just fine, including 2 at this location. hundreds of trouble free world class transparent listening.
 
The price for a fully assembled amp has dropped down to $129 at JDSLabs...thats FULLY assembled!!!
 
That said all things electronics will have issues from time to time but for the most part they run and run and run....and there are not tubes or real heat issues to deal with.
 
Who knows why or why not this guy took the stage left scenario....but the O2 amp is living out in the wild just fine.
 
A.

 

[doof-ed]

Call it a crazy question, but would it be possible to build the o2 with the dac in the same housing still with the batteries?
 
I know this is rather impractical and i've read that it wont fit in the standard housing together, but it was an idea I had. 
 
When I get some more income generated i'll be keen to build one of these - just an o2 kit - no shed means no custom work

 

[bada bing]

You can shoehorn the ODAC board underneath the PCB in the battery area, it has been done but is a tight fit.
 
Just my opinion, but the batteries on the O2 are the dumbest part of the design. Having the batteries
necessitates overcomplicating the power supply section. The amp itself is too large IMO for a portable.
The batteries are a significant portion of the cost. And the biggest reason is the clipping level changes
between battery power and wall power.

 

[adydula]

I agree somewhat on the batteries if your going mobile etc...
 
On the other hand many of us use the amp in a desktop mode and dont really care but there is a positive side to this as well.
 
There are many discussions about AC power and its worts...true or not....and having batteries and using pure DC takes all that out of the way....
 
I have one with batteries and one without, one with an integrated ODAC and one with an external.
 
A.