[miceblue]

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Nothing unusual pops up for me while listening to that track with an AKG K 701 on the ODAC and O2 units I have. Adjusting the potentiometer yielded nothing unusual either, unless the cymbal sounds are what you're referring to as "scratching sounds".

Nooope. It'd hit you like a sack of bricks if yours had the same problem that mine keep getting. It's not terrible, but its quite noticeable. I just used this track because it's pretty bassy.

Yup I don't get anything with my sensitive V-MODA M-100's either. That's kind of odd that it happened to you 3 times now though.

 

[MrMateoHead]

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my original post referred to the O2 vs E9 with the HD600's (300 ohms), so the high output impedance of the E9 doesn't really effect the synergy between the E9 and 600's.
I'm not in love with the E9, just wondering why many feel the O2 is leaps and bounds ahead of it with high impedance cans. (I've never heard the O2, and am debating getting one - just trying to decide if spending $150 is worthwhile in my case, considering that I already own the E9)

The O2 is superior to the E9 in every way for starters. It is technically portable, it supports a wider range of headphone impedence (16 ohm - whatever), and makes similar if not more power (not sure haven't memorized specs). The thing puts out no noise whatsoever, and the gain switch is handy for using weaker sources like phones and Mp3 players.
 
That said, if you like the E9 and it is working for you, keep it and save your money. I wouldn't have got an amp period if my laptop had enough juice to run my current phones (it didn't).

 

[MrMateoHead]

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So... For the third time now I am experiencing noise in the right channel of my o2 while I move the pot during a bass test..

My first o2 I replaced the pot on and it fixed the problem for a while.. When it came back I bought a completely different o2 from jds thinking maybe the problem was my particular o2.. Nope, seems like it's just a problem these pots have. And not a huge problem at that.. It can just be annoying while I'm running sine sweeps.

http://www.youtube.com/watch?v=PMd9eYXT0mM

Please, for the love of all that is headphones. Could a few of you listen to this track and move your volume pot around and tell me if you get any scratching in the right channel?

+1 to getting "scratching" when moving volume knob around in right channel. Weird.
 
Stops when the volume knob stops. This does not occur with anything else I have ever listened to so far, so I am not sure why that uncomfortably bassy music would do it.
 
I once lost the Left channel completely one day. Had to unplug the amp completely, and plug everything back in. Seemed to be a possible problem at the headphone jack.

 

[RustA]

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+1 to getting "scratching" when moving volume knob around in right channel. Weird.
 
Stops when the volume knob stops. This does not occur with anything else I have ever listened to so far, so I am not sure why that uncomfortably bassy music would do it.
 
I once lost the Left channel completely one day. Had to unplug the amp completely, and plug everything back in. Seemed to be a possible problem at the headphone jack.

 
I don't think it's weird since I experienced that with several amps (rarely but yes)... It does not affect the sound at all, you know (only if you are going to slowly manipulate with the knob over longer period of time, you would possibly keep listening to that "scratching" ,-) ).
 
I would personally check the potentiometer, if it "fits and sits" exactly where it should be and how it should be... Unscrew the panel and the knob and have a look, then get it together again and try to manipulate with it again.

 

[lorriman]

So... For the third time now I am experiencing noise in the right channel of my o2 while I move the pot during a bass test..


http://www.youtube.com/watch?v=PMd9eYXT0mM

I have this problem and posted a message about it on diyaudio. There was no resolution.

 

[MrMateoHead]

It may be worth adding that, I only pick up the scratch on that youtube video - not on any of my other music.
 
And with that, there is the variable of the audio signal going through windows -> my DAC -> my amp -> my headphones.

 

[chrislangley4253]

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It may be worth adding that, I only pick up the scratch on that youtube video - not on any of my other music.
 
And with that, there is the variable of the audio signal going through windows -> my DAC -> my amp -> my headphones.

it's not the video. Play anything else bassy and you will hear it.

 

[lorriman]

I've just tested this with silence and with a 60Hz sine tone. It doesn't do it with a silence track. If I lower the volume of the source (my laptop) to 6 (Vista) then I only hear it at the end of the O2's volume control on 2.5x gain, whereas otherwise it's prominent already at 11 o'clock. This is true both of O2 stand-alone and O2/ODAC.

 

[JakeJack_2008]

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+1 to getting "scratching" when moving volume knob around in right channel. Weird.
 
Stops when the volume knob stops. This does not occur with anything else I have ever listened to so far, so I am not sure why that uncomfortably bassy music would do it.
 
I once lost the Left channel completely one day. Had to unplug the amp completely, and plug everything back in. Seemed to be a possible problem at the headphone jack.

 
Hold on, not so fast, please.  Right now I'm sratching my forehead and debating whether I should forget about the O2 or not.
But rereading Your post and highlighting the key sentence in red I see that the weird sratching occurs only while you're playing with the volume  knob.
So perhaps this is nothing serious, I hope. Also, what model of the O2 (the pot, headphone jack, ...)  are we talking  here about:  from JDS Labs, ..., DIY-made?

 

[chrislangley4253]

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Hold on, not so fast, please.  Right now I'm sratching my forehead and debating whether I should forget about the O2 or not.
But rereading Your post and highlighting the key sentence in red I see that the weird sratching occurs only while you're playing with the volume  knob.
So perhaps this is nothing serious, I hope. Also, what model of the O2 (the pot, headphone jack, ...)  are we talking  here about:  from JDS Labs, ..., DIY-made?

I don't think it's anything serious. Just an issue that the pots sometimes develop. I have had it happen twice on a DIY O2 and once now on my JDS Labs. It's really non-intrusive, I wouldn't let it keep you from getting the amp. I still recommend it, anyways.

 

[mikeaj]

I've never had an issue with the pot on the one I built.  I wiggled it nonstop for a minute listening to that track and heard nothing like that.
 
Is it the right channel for everybody, if it happens?

 

[chrislangley4253]

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I've never had an issue with the pot on the one I built.  I wiggled it nonstop for a minute listening to that track and heard nothing like that.
 
Is it the right channel for everybody, if it happens?

 
Well, I've only had it in the right channel three times. That might just be coincidence though.

 

[stv014]

Probably the pot simply has a minor contact problem while it is being adjusted, and the signal gets amplitude modulated by noise as a result. When there is no signal, it does not result in audible noise; that is also why DC on pots should be avoided, as noted by the designer of the O2, too. It is most noticeable with loud bass because that (and DC) is what can produce the highest level of modulation noise without masking it. The problem could affect the right channel more often because of the way that particular model of pot is built.

 

[adydula]

Chris, what kind of WIERD stuff is that anyway!!
 
OMG..
 
No issues here with it?
 
Alex
 
oh...what the doctor told me .."dont do that"...

 

[Draygonn]

Please, for the love of all that is headphones. Could a few of you listen to this track and move your volume pot around and tell me if you get any scratching in the right channel?

Mine has the annoying scratching noise issue. It was fine for the first 6 months or so.

Is it the right channel for everybody, if it happens?

My right channel is affected.