[oyster]

 
Quote:

 
Check the current rating as well, though likely it's at least 200 mA or so and thus okay.
 
It may be okay.  If you have a multimeter to measure the voltage unloaded, then that should tell you.  The voltage you measure without the adapter plugged into the amp (so unloaded) should be about 13.5V AC or so.  In fact the "default" AC adapter recommended, the WAU12-200 (which I and many others use), is rated for 12V nominal but is more around 13.5V unloaded, so your 13V adapter may be okay.  It depends also on what exactly the voltage is you're getting from the wall.  Note that the transformer output voltage drops, the more power you pull from it.
 
If the rating is too low, then under sustained heavy power consumption, the voltage out of the transformer to the 12V regulators may drop close enough to 12V that the regulators get cranky and start to misbehave, meaning that the power supply rails have more noise on them, degrading the performance a little bit.  Heavy power consumption pretty much means bench testing max output into low impedances--this probably won't happen in practice unless you're listening really load on a planar magnetic headphone while charging batteries (which are depleted) simultaneously.  If not under sustained heavy power consumption, a suitable adapter on the "low" side is just as good, maybe even preferred since there will be less waste heat generated by the regulators.

Many thanks for the response. Although i could not understand most of it......am a big zero in electronics
 
The wall output is 240V. Just measured the unloaded output of the adapter, it's 13.05V. Should be ok then...right?
Also, would you still suggest getting a >14V supply for a better performance.....maybe more volume output?
 

 

[mikeaj]

Quote:

Many thanks for the response. Although i could not understand most of it......am a big zero in electronics
 
The wall output is 240V. Just measured the unloaded output of the adapter, it's 13.05V. Should be ok then...right?
Also, would you still suggest getting a >14V supply for a better performance.....maybe more volume output?

 
13.05V is too low for it to work (apparently), but it practice it might be okay with some headphones maybe?  I'm not that familiar with how those regulators behave, and I didn't check the data sheet.  How much current is the adapter rated for?  There should be a number given like 0.5A or 200 mA or something like that.
 
This is a situation where more (voltage) past a certain point is not better, but you're definitely under that point.
 
The text from the article is this:
Quote:

AC Wall Transformer – There has been some confusion over the wall transformer and it’s a critical component. Most wall transformers put out DC but the O2’s power supply requires at least 13.5 volts AC. The ideal transformer would be rated at 14 - 16 VAC and 400 mA or higher. In North America the Triad WAU12-200 from Mouser is rated at 12 volts but is really about 13.5 VAC with no load, and on normal 120 volt line voltage works fine for anything but full power sine wave testing or driving rare low impedance power hungry cans. If your line voltage is below 117 VAC  or 235 VAC, and/or you plan to drive difficult low impedance headpones (i.e. HiFiMan planars), I would suggest a 14+ VAC transformer at 400+ mA. The best Mouser transformers are the WAU16-400, 412-218054 or WAU16-1000 CUI. But those are more expensive than the WAU12-200. The WAU20-200 also works for higher impedance headphones. At least some European 230 volt input 12 VAC output transformers only measure around 11.5 to 12 volts on normal line voltage and won’t work (especially if designed for halogen lights). You can also change the power jack to a 5.5mm x 2.5mm version if needed to match the plug of different wall transformers.

 

 

[oyster]

Quote:

 
13.05V is too low for it to work (apparently), but it practice it might be okay with some headphones maybe?  I'm not that familiar with how those regulators behave, and I didn't check the data sheet.  How much current is the adapter rated for?  There should be a number given like 0.5A or 200 mA or something like that.
 
This is a situation where more (voltage) past a certain point is not better, but you're definitely under that point.
 
The text from the article is this:
 

The current is rated at 1A. I am using the amp with 150ohm, 92db Yamaha HP50A . The source is HP out from my mp3 players Clip+/touch 3g/Nokia X5. While at low gain i think i definitely need quite more volume.
 

 

[darren700]

Cant wait for the ODA to come out... so anxious

 

[Lil' Knight]

Spent a couple of hours last weekend building the amp. Pairing with another low budget DAC (Grub) now. I'm getting some pretty nice tunes, excellent value for the money, considering how much they cost ($35 + $35).

However, comparing the O2 with the B22 would be a real joke to me. It's one heck of a fine sounding amp, but by no way on the level of the B22. In the most optimistic way, I'd say it can stand against the M3 pretty well. I also don't think I prefer the O2 than another DIY amp, the Minimax ($250). Still, for $35, I can't ask more.

 

[LizardKing1]

I think the big question was, if all the levels of distortion and frequency coloring on the O2 are below audibility, and the ones on the Beta22 are even lower, then there's no way these 2 amps could be distinguishable. Kind of like if you have have a sphere with 1 micron diameter and another one with 0.0001 micron diameter, in terms of sight it's irrelevant which one is smaller because you can't see any. Why is the O2 not "on level" with the Beta22 in terms of sound? Besides the voltage output, I assume they should be exactly the same to us, and so very much comparable.

 

[129207]

Quote:

Why is the O2 not "on level" with the Beta22 in terms of sound?

Because actually admitting this after you spent $1K+ on a B22 would implode the universe itself. 

 

[Lil' Knight]

Because actually admitting this after you spent $1K+ on a B22 would implode the universe itself. 

Not worth spending time replying to post like this... :rolleyes: How much experience do you have with the B22? :rolleyes:

 

[129207]

Quote:

Not worth spending time replying to post like this...

How much experience do you have with the B22?

I am not here to rain on your parade or question the way your ears work. Your opinion is as valid as mine. I just like seeing the universe implode once in a while.

 

[Llloyd]

this thread has certainly died down since it moved sections, which is quite unfortunate

 

[zzffnn]

I am sorry if my following comment offends anyone. And my comment herein is not aimed at anyone specifically. But let us provide HELPFUL impression in this thread.

if you have actually listened to O2 and Beta22 or Amp XYZ side by side, indicate such like Lil Knight did. If you have not and are speculating, please also indicate that so others can take your comment with caution.

Please note that some are simply providing subjective preference here. You can not predict preferrence without listening to equipments. More perceived transparency may not always be preferred by human ears.

 

[maverickronin]

Quote:

this thread has certainly died down since it moved sections, which is quite unfortunate

"Mission Accomplished"

 

[ProjectDenz]

Quote:

"Mission Accomplished"

 

[LizardKing1]

 
Quote:

I am sorry if my following comment offends anyone. And my comment herein is not aimed at anyone specifically. But let us provide HELPFUL impression in this thread.
if you have actually listened to O2 and Beta22 or Amp XYZ side by side, indicate such like Lil Knight did. If you have not and are speculating, please also indicate that so others can take your comment with caution.
Please note that some are simply providing subjective preference here. You can not predict preferrence without listening to equipments. More perceived transparency may not always be preferred by human ears.

You're right. I never listened to the Beta22. It's just one of those times where I don't see how it could help. I never listened to music using a 650$ Audioquest USB cable either, but I have no reason so assume it will be different from a Monoprice 2$ USB cable. People have every right to have a subjective opinion, and objective assumptions, and have these two fields contradict one another.

 

[zzffnn]

Quote:

 

You're right. I never listened to the Beta22. It's just one of those times where I don't see how it could help. I never listened to music using a 650$ Audioquest USB cable either, but I have no reason so assume it will be different from a Monoprice 2$ USB cable. People have every right to have a subjective opinion, and objective assumptions, and have these two fields contradict one another.

 
Quote:

I think the big question was, if all the levels of distortion and frequency coloring on the O2 are below audibility, and the ones on the Beta22 are even lower, then there's no way these 2 amps could be distinguishable. Kind of like if you have have a sphere with 1 micron diameter and another one with 0.0001 micron diameter, in terms of sight it's irrelevant which one is smaller because you can't see any. Why is the O2 not "on level" with the Beta22 in terms of sound? Besides the voltage output, I assume they should be exactly the same to us, and so very much comparable.
 

 
I think your "objective assumption" over-simplify reality too much, such that it does not make sense. You can not compare 2 amps based on "distortion and frequency coloring" alone. Your assumption of different voltage output is moot as well, because a person can easily adjust volume, gain and/or input to matched levels.
 
You listen to equipments with your ears too, correct? If you base your "objective assumption" on 3 data points and in reality there are 100 unknown data points, then your assumption would not work. In this case, a real word listening would provide a summary of those 103 data points. No doubt that listening is subjective, but when it is from actual owners, it will be helpful, especially when you know that owner X has the same preference as yourself. 

Cable vs. cable is different than amp vs. amp. I myself do not believe in cable either (I did compare pure silver cable vs monoprice cable and found no difference).