hello guys, I wanted to ask about this transformer: http://www.evernote.com/shard/s102/...fda580616a83/72735cbd9d3d3e3dda12874e98482e60
this is the one I have, if I assemble it, can I use it to power and charge my o2 ?
my concern is that I havent read VAC on the output
thanks
It will work fine if you wire it up for 20V (series). Your regulators may get a bit on the hot side but everything will operate within spec, so you're good to go.
wow, thank you. there will be a voltage drop so it isnt exactly going to reach 20v. the "series" that you have mentioned is the same as the way it was shown on my link?
It sound very jagged, it happen to both channels and was on battery. This morning when I tested it without input, the headphone was silence for 1about 0 second, then a 'tub, tub.....' sound in interval about 0.5 second come.
wow, thank you. there will be a voltage drop so it isnt exactly going to reach 20v. the "series" that you have mentioned is the same as the way it was shown on my link?
Yeah. Series wiring means that you're wiring one half of the transformer to feed the other... like how you stick D batteries end to end in a flashlight.
Here's a good link for it.
base on your link, i must be following the series on figure 1. which is just the same diagram on my link.
however, if you refer to my link, it mentioned:
Electrical Specifications (@25C)
1. Maximum Power: 10.0VA
2. Input Voltage – Series: 230VAC @ 50/60Hz, Parallel: 115VAC@ 50/60Hz
3. Output Voltage – Series: 20.0V CT@ 0.5A, Parallel: 10.0V @ 1.0A
4. Voltage Regulation: 20% TYP @ full load to no load
5. Hipot: 3500VAC between primary to secondary and windings to core.
CT is center tapped right? am i going to follow the diagram on figure 2?
That sounds like the rapid clicking that happens when the battery is low. It should go away as soon as you plug the AC back in. This is what RocketScientist mentioned on his blog:
ok, will try that once I reach home on Saturday, I am outside without the charger now.
How long it need to charge the battery if I am using a 75VA, 14Vac trans as input? I charge it 4 hour before I take it out, I think is not enough.
Thanks.
NiMH batteries should be charged at around 10% of their rated capacity, i.e. around 20mA, so should take 10 hours to charge from flat. Charging them faster than this can overheat them. NiMH batteries generally need 4 - 5 full charge/discharge cycles before reaching their maximum capacity.
I for one would like to again put in a big "thank you" to RS and others who made the group buy(s) happen. I've really been enjoying my O2 the last month or so and am really looking forward to the ODA/ODAC build coming up. I'm also saving my pennies for some HD-700's, which I think the O2 should handle nicely.
I too have been amused by some of the O2 reviews by subjective types. Generally good reviews, but usually reluctant to put them ahead of much more expensive amplifiers (even without AB testing).
But I'm with RS when it comes to subjective reviews: without some kind of direct comparison (ABX or blind AB), I don't think they're worth much. I would be incredibly impressed if anyone could truly tell this apart from another good, low output impedance, FLAT (i.e. non-tube) amplifier that has a similar noise floor (noise can be a dead giveaway). I have yet to see anyone do that consistently. I swear some of these guys just make stuff up to have something to write.
I too have been amused by some of the O2 reviews by subjective types. Generally good reviews, but usually reluctant to put them ahead of much more expensive amplifiers (even without AB testing).
But I'm with RS when it comes to subjective reviews: without some kind of direct comparison (ABX or blind AB), I don't think they're worth much. I would be incredibly impressed if anyone could truly tell this apart from another good, low output impedance, FLAT (i.e. non-tube) amplifier that has a similar noise floor (noise can be a dead giveaway). I have yet to see anyone do that consistently. I swear some of these guys just make stuff up to have something to write.
Hi Everyone,
I made my second 02 amp with a gain of 1x and 2.5x in mind, so i soldered resistors R17 and R21 to positions R19 and R23, respectively, and left R17 and R19 empty on the PC board. I plug in my headphones and there's a channel imbalance. Would this have anything to do with me repositioning the resistors?
After messing with it a bit I found that wiggling the input jack up and down would cause it to go in and out of balance, but when left alone, it's defaulted as imbalanced. I'm suspecting this to be the culprit.
Note on Imbalance: It sounds like the left channel gain is working fine; I hear a difference in loudness switching from low to high gain. The level of loudness on the right channel stays the same regardless of the gain setting, think its stuck on the high gain.
Has anyone experienced a similar problem? Any advice on fixing this? Any help is much appreciated.
I made my second 02 amp with a gain of 1x and 2.5x in mind, so i soldered resistors R17 and R21 to positions R19 and R23, respectively, and left R17 and R19 empty on the PC board. I plug in my headphones and there's a channel imbalance. Would this have anything to do with me repositioning the resistors?
After messing with it a bit I found that wiggling the input jack up and down would cause it to go in and out of balance, but when left alone, it's defaulted as imbalanced. I'm suspecting this to be the culprit.
Note on Imbalance: It sounds like the left channel gain is working fine; I hear a difference in loudness switching from low to high gain. The level of loudness on the right channel stays the same regardless of the gain setting, think its stuck on the high gain.
Has anyone experienced a similar problem? Any advice on fixing this? Any help is much appreciated.
Hmmm, I don't agree with that sentiment at all.
I don't want to comment on the O2's sound quality here, but I think it's important to note that subjectivity is the ultimate judge of ALL audio equipment. If you don't trust your ears, I think you're missing the point of listening in the first place. As one person put it so bluntly "customers don't listen with their scope."
I agree that if people make outrageous claims they should back them up with some data. But if someone simply relates their opinion, it's hardly the case that you can just write it off in the manner you have. The point of relating experience on a forum like this is to build a consensus, it's how sites like Amazon leverage a community to produce a real understanding of how a product performs.
I don't write off subjective listening, but I do believe it needs to be done in a blind AB setting in order to be of any value. The idea of sighted subjective listening is way too biased in my opinion. I would definitely give weight to a properly level-matched ABX test where there were significant differences reliably detected. The brain is just too unreliable otherwise.
But we're getting off-topic here and this has been discussed ad nauseum in countless other threads I'm sure.
