Here is the same jack from CUI, a different manufacturer, via Digikey:
Digi-Key - CP1-3555NG-BE-ND (Manufacturer - SJ1-3555NG-BE)
what the? well i'm kind of stunned right now. I was playing around and decided to go directly from my motherboard's soundcard 1/8" out into my O2.
I would never do this with other amps b/c the noise is quite audible but to my amazement its totally silent.
on low gain i can turn the volume all the way up with NO noise at all, on hight gain i have to go to about 12 oclock before i start to hear minimal noise, which would probably blow my eardrums with music on.
what is it about this amp that makes it so insulated from computer noise?
I would never do this with other amps b/c the noise is quite audible but to my amazement its totally silent.
on low gain i can turn the volume all the way up with NO noise at all, on hight gain i have to go to about 12 oclock before i start to hear minimal noise, which would probably blow my eardrums with music on.
what is it about this amp that makes it so insulated from computer noise?
Two things that I can think of: high input impedance of 10kΩ and a real ground plane with the audio's common dumping into it... which is also attached to the aluminum enclosure of the amp.
Full gain left channel, attenuated right channel
This is my first diy electronic project. It was fun. Everything is together, measurements looked good, plugged in headphones and source -- all good. Pressed play on source (an ipod), full volume left channel not effected by volume knob, right channel seems to work fine. I am slowly trying all the diy tests again and making my way through the more in depth tests.
Since I am new -- I am not confident that I would know what measurement was out of whack unless the "details" page has the measurement value explicitly.
This is my first diy electronic project. It was fun. Everything is together, measurements looked good, plugged in headphones and source -- all good. Pressed play on source (an ipod), full volume left channel not effected by volume knob, right channel seems to work fine. I am slowly trying all the diy tests again and making my way through the more in depth tests.
Since I am new -- I am not confident that I would know what measurement was out of whack unless the "details" page has the measurement value explicitly.
Guys, i need some help....
I'm starting my second try of build a headphones amp...the first try i make one by my own...but never finished it...so i opted for a DIY one....eheh
I already buy this material:
Kilo Intl ML-50-6MM Clear Knob
Machined O2 Front Panel
O2 Printed Circuit Board
Now i need to buy the components and a B2 case....someone can knows were can i buy a complete kit of components and this case...? I'm from portugal BTW...
Thanks
I'm starting my second try of build a headphones amp...the first try i make one by my own...but never finished it...so i opted for a DIY one....eheh
I already buy this material:
Kilo Intl ML-50-6MM Clear Knob
Machined O2 Front Panel
O2 Printed Circuit Board
Now i need to buy the components and a B2 case....someone can knows were can i buy a complete kit of components and this case...? I'm from portugal BTW...
Thanks
I really enjoy this amp. I have a question for RS.
Would it be possible to feed the amp with DC, mainly to charge the batteries. I don't mean necessary on the onboard AC connector, I could tap someware and add an extra DC input.
I ask because small switching psu are much lighter than transformers, and I use the amp when I am travelling. I use it almost aleays on batteries and connect to AC only to recharge.
Thanks,
Davide
Sent from my N-04C using Tapatalk
Would it be possible to feed the amp with DC, mainly to charge the batteries. I don't mean necessary on the onboard AC connector, I could tap someware and add an extra DC input.
I ask because small switching psu are much lighter than transformers, and I use the amp when I am travelling. I use it almost aleays on batteries and connect to AC only to recharge.
Thanks,
Davide
Sent from my N-04C using Tapatalk
Have you tried Farnell? You can try uploading the BOM, though it'll take a day. The b2 case seems to be listed as US stock so you may want to try ebay to avoid the fee.
If you prefer to have everything finished take a look here. Jokener took care of the first GB for europe and now he has another GB up and running for late comers.
http://www.diyaudio.com/forums/group-buys/201323-o2-amplifier-kit-pcb-groupbuy-worldwide.html
EDIT:
agdr, True, i haven't checked that thread since the start...
Had forgotten about that, should probably try to get a hold of him as well because i'm two boards short.
Last edited:
Well I was going to suggest Jokener's worldwide group buy. I just had a look at that thread, which I hadn't gone back to in awhile.... looks like that is why you are back here!
Try jtktam in Canada. He is selling kits too. The last few posts have prices and says he will do it worldwide:http://www.diyaudio.com/forums/group-buys/198388-o2-parts-canada.html
EDIT: QRikard - looks like we were both composing at the same time! Check out the last few posts in Jokener's thread - something has happened, it seems...
Last edited:
troubleshooting build
There seem to be no solder bridges. (The solder is not great, but nothing seems to be bridging and everything seems secure.)
I retested resistances -- resistances are all right.
I retested voltage. I believe all the diodes tested correctly. But there was some funky stuff -- pin 4 and pin 8 of U4 do not drop below 1v with a battery removed. -- The details page indicates that this means broken MOSFET. Additionally pin 2 of U2 is near -11.8v instead of -8.4, this indicates that U2 is broken (or maybe Q1 or Q2).
I retested the headphones (for the heck of it) with the AC and without batteries. Everything sounds nice. and the volume knob attenuates the right channel but not the left -- could this be due to U2 or the MOSFET being broken, or must something else also be improper?
There seem to be no solder bridges. (The solder is not great, but nothing seems to be bridging and everything seems secure.)
I retested resistances -- resistances are all right.
I retested voltage. I believe all the diodes tested correctly. But there was some funky stuff -- pin 4 and pin 8 of U4 do not drop below 1v with a battery removed. -- The details page indicates that this means broken MOSFET. Additionally pin 2 of U2 is near -11.8v instead of -8.4, this indicates that U2 is broken (or maybe Q1 or Q2).
I retested the headphones (for the heck of it) with the AC and without batteries. Everything sounds nice. and the volume knob attenuates the right channel but not the left -- could this be due to U2 or the MOSFET being broken, or must something else also be improper?
Suggestion: start with figuring this one out first. -11.8V is essentially the negative rail (negative power supply) voltage with the unit running on AC power.
The chip pins are numbered counter-clockwise looking at it from the top, starting with the "dot" in the upper left corner being pin 1. Check that you are measuring the right pins.
With the power switch on and the headphones unplugged, measure between ground (the metal shell of the gain switch) and pin 8 of U2, then between ground and pin 4 of U2 and see if you get the 12.0Vdc and -12.0Vdc rails, +/-0.2Vdc or so with the O2 running on AC. Be very careful on the IC not to short pins together when measuring!
Helps to have the DMM test probe resting on the edge of the plastic IC socket to stabilize it at each pin. If you are using batteries do all these measurements once for AC plugged in, with the batteries out, then again with the AC unplugged and the batteries in. In the case of batteries the U2 pins 8 and 4 should read somewhere around +8.4Vdc and -8.4Vdc, +/-1.5Vdc or so depending on battery charge level.Then measure ground to pin 2 of U2 again for both cases (AC only and batteries only) and see what you get.
What you are testing here is the condition of your power supplies going into the mosfets, along with the U2 pin 2 reference voltage divider.
Maybe RocketScientist will log on and jump in here.
Last edited:
Charging.......
Hi all,
My amp is done and sounds amazing. The only issue I am having is with the batteries. I have tried 2 different sets including the blue Tenergy 250's RS recommended. After keeping the amp plugged in for around 24 hours I only get about 10 minutes of battery time before the amp does the low power "stutter." All is well when i plug it back in. I guess my amp is not charging? Everything checked out IAW the testing section. Any ideas?more info
Thanks,
Todd
Update: now it stutters even with power plugged in. The weird thing is it is intermittent. It stutters, then corrects itself......ahhhhhhhh
Hi all,
My amp is done and sounds amazing. The only issue I am having is with the batteries. I have tried 2 different sets including the blue Tenergy 250's RS recommended. After keeping the amp plugged in for around 24 hours I only get about 10 minutes of battery time before the amp does the low power "stutter." All is well when i plug it back in. I guess my amp is not charging? Everything checked out IAW the testing section. Any ideas?more info
Thanks,
Todd
Update: now it stutters even with power plugged in. The weird thing is it is intermittent. It stutters, then corrects itself......ahhhhhhhh
Last edited:
I'M AN I-D-I-O-T!!!!!!!!! It only happens when using Pandora..........
Ahh..."Buffering..." It's interesting that plugging it back in appeared to fix the problem. A strange coincidence there!
RocketScientist probably has a slicker way to do it, but I've just posted one way here:
http://www.diyaudio.com/forums/head...rc-diode-cap-heatsink-mods-4.html#post2856990
I wrote up this reply and then realized it was essentially a modification. I'm trying to keep mods out of the main O2 thread here, so I stuck it in my mod thread instead.
Good luck! Please post a picture if you build it.