gootee, have you had a look at the O2 layout? If yes, do you have any insight into RS's design? It seems to me that the output has caps placed nearby, but the voltage gain stage appears "naked" (though I didn't examine it as closely I could have). I don't remember RS blogging on this particular aspect of his design, at least in comparison with his other in-depth notes.
I'm not sure what you mean. What "identifying" are you asking about? Do you have the BOM?
Hi all, just after a bit of advice. I've built my O2 and was wondering if anyone knows how i can work out the gain resistor part of it.
I'm not after deafening sound but even on full volume its still not as loud as my phone for example. I am taking my output from a E-MU 1010pci sound card and the outputs not amplified like a ipod or 'normal' pc sound card.
Any help would be much appreciated.
I'm not after deafening sound but even on full volume its still not as loud as my phone for example. I am taking my output from a E-MU 1010pci sound card and the outputs not amplified like a ipod or 'normal' pc sound card.
Any help would be much appreciated.
All the parts were in the same bag, so I had to check the values of each resistors, which is easy, but now I have 8 ceramic caps that I can't figure their values. Here's what I have:
4x with BC 221 on it
2x with BC 105z
1x 223 E1M
1x 213AFP
That's what is writen on them an I don't know what it means
http://www.diyaudio.com/forums/headphone-systems/217086-building-o2-headphone-amp.html
In that link are a bunch of photos, and the first links on the top page take you to nwavguy's pages, which have all the info you will ever need about this project.
In that link are a bunch of photos, and the first links on the top page take you to nwavguy's pages, which have all the info you will ever need about this project.
I was in exactly your position; I used a multimeter for the resistors and photographs for the capacitors.
Why not compare the numbers on the parts with the values in the bill of materials?
Sent from my mobile thinger using the tapawhatsit
Those number codes signify picofarads. 1st digit, 2nd digit, tens multiplier. So...
221 = 220pF (C11, C12, C19, C20)
105 = 1000000pF = 1μF (C1)
223 = 22000pF = 0.022μF
213 = 21000pF = 0.021μF
The last two are for C16 & C21. Probably an availability issue, so a cap 1 nanofarad less was substituted. Virtually no difference where it's used in the O2 power management circuit.
221 = 220pF (C11, C12, C19, C20)
105 = 1000000pF = 1μF (C1)
223 = 22000pF = 0.022μF
213 = 21000pF = 0.021μF
The last two are for C16 & C21. Probably an availability issue, so a cap 1 nanofarad less was substituted. Virtually no difference where it's used in the O2 power management circuit.
I had difficulty with those capacitors, too, but I guess I got them right. Mine were also different than what they were in O2 reference pictures. Capacitor calculator really helped with them.
Anyway, my subject was that I just plugged my O2 to a DC adapter and now it outputs no sound anymore. It still "works" with one battery though, but clips very badly.
Where could I get some spare parts for the O2 in EU? Also do you know which parts could potentially be broken with it?
Anyway, my subject was that I just plugged my O2 to a DC adapter and now it outputs no sound anymore. It still "works" with one battery though, but clips very badly.
Where could I get some spare parts for the O2 in EU? Also do you know which parts could potentially be broken with it?
If you go back a couple pages, when I did that it cooked the 4556 chips. It sounds like you are down a battery too? Make sure you replace the damaged one with the exact same, or just replace both.
Sent from my mobile thinger using the tapawhatsit
4562 and 8620 may replace the 2068 effectively. 8066 may be too fast of a chip for this board. Or not.
Give the stock parts a few hours burnin and you will be even more impressed. And i do mean few.
Sent from my mobile thinger using the tapawhatsit
For spares take help from swalter of "head n' hifi".
BTW What really happens if you connect DC adapter? Does the o/p is busted if h/p is connected apart from 1 bat. not getting charged? Or does the PM of O2 offers some protection from DC adapter.?
I wont be doing this trial/mistake
on my O2
Last edited:
I measured my batteries, they were about 8.8V each. Anyway weird thing, yeasterday my O2 worked for few minutes fine, but then as I turned power on and off, it stopped working again.. I'll take some measurements and post here later..
Hi, finally found some time to read up on the thread.
I guess the set came from me, just to point out that the caps are actually packed like this from mousers supplier, I just take two out of a bag of a thousand and do not really read what is printed on them when preparing the kits.
Taking the tolerance of 20% into account those caps have, even a 173 would still be within specs as long as it has a tiny bit of positive tolerance
Stefan
Stefan