[maverickronin]

Quote:

Is there any advantage to using it at the higher gain settings if you can get enough volume on the pot at 1X on low impedance or high impedance headphones?
 
Is there an advantage to using the AC adapter as far as speed of bass transients or anything?  It's just so low distortion and clean on batteries I haven't even bothered with plugging the adapter in yet.

Voldermort has the gain and battery or AC specified on most (if not all) of his measurements so you can decide for yourself.
 
The short answer is that the AC pretty much just gives you more power and raising the gain increases the noise and distortion a tiny bit.  You'd have to use an amazingly high gain before it became audible though.

 

[Br777]

he says on his blog that using lowest gain possible is always best on any amp.  sorry i cant remember the details, but as usual he makes a good case for it.
 
 

 

[estreeter]

I find the negative impacts of higher gain clearly audible, and in general I far prefer amps with sufficient grunt on low gain to allow me to avoid 'cranking it'. The EHp-O2 is the first amp, portable or otherwise, that I have owned which made high gain desirable.
 
To be fair, I think nwavguy specified the original gain settings at 2.5 and 6.5 (see below), and I was fine with that until some bozo posted that they felt that 'low gain' would still be too much for sensitive IEMs. I had Oliver change my settings to '2x and 5x', respectively, and I now believe it was a mistake.
 
From Voldemort's blog:
 
The standard gains are 2.5X and 6.5X but can be internally changed to anything from 1X to 12X.
 
With my 150-ohm RE262 IEMs, low gain just doesnt have enough juice unless I crank the volume around to 3pm and beyond (!) : unthinkable on any of my other amps as it really would blow my head off. The situation is a little better with my 32-ohm cans, but its disappointing that such a 'large' amp seems to have less power than most of my portables. Even with high gain, I dont find it to be a particularly powerful amp - I guess I should have left well enough alone and ignored the comment from our bat-eared friend with the thousand-dollar IEMs.  :banghead:

 

[khaos974]

I don't think that the gain structure of the O2 allows the potentiometer to clip the signal, I actually see no reason why the it shouldn't be used at 3 o'clock or even fully turned.

 

[Br777]

with my es5's and my gain clipped to 1, i can turn the knob about a centimeter at most before its too loud.  With my LCD-2's, the loudest i can go is 9pm
 
estreeter what is your source? i ask because if i use a source like my clip+, even with the volume all the way up on the Clip, i find i have to turn the volume up WAY more on the same headphones.. maybe this issue.. whatever it is..maybe voltage output?, has something to do with it.
 
try another source and see if you have the same issue.
 
by the way, its not my bat ears
its that my iem's are very low impedance and high sensitivity, they are expected to behave the way they do.  Yours are probably the oppisite.. best to check ahead of time.
 
and FYI my average listening level is measured at around 73-80db, which is considered average.

 

[maverickronin]

Quote:

I don't think that the gain structure of the O2 allows the potentiometer to clip the signal, I actually see no reason why the it shouldn't be used at 3 o'clock or even fully turned.

 
Can't the 4556s can run out of current and clip into loads less than 50 or so ohms?
 
Also even from a source with a volume control, I wouldn't run any amp this strong at max volume like that unless you only ever have really inefficient headphones hooked up to it.  One click or pop from your source could ruin some pretty expensive headphones and give you a very unpleasant ringing in your ears.

 

[limpidglitch]

Quote:

I find the negative impacts of higher gain clearly audible, and in general I far prefer amps with sufficient grunt on low gain to allow me to avoid 'cranking it'. The EHp-O2 is the first amp, portable or otherwise, that I have owned which made high gain desirable.
 
To be fair, I think nwavguy specified the original gain settings at 2.5 and 6.5 (see below), and I was fine with that until some bozo posted that they felt that 'low gain' would still be too much for sensitive IEMs. I had Oliver change my settings to '2x and 5x', respectively, and I now believe it was a mistake.
 
From Voldemort's blog:
 
The standard gains are 2.5X and 6.5X but can be internally changed to anything from 1X to 12X.
 
With my 150-ohm RE262 IEMs, low gain just doesnt have enough juice unless I crank the volume around to 3pm and beyond (!) : unthinkable on any of my other amps as it really would blow my head off. The situation is a little better with my 32-ohm cans, but its disappointing that such a 'large' amp seems to have less power than most of my portables. Even with high gain, I dont find it to be a particularly powerful amp - I guess I should have left well enough alone and ignored the comment from our bat-eared friend with the thousand-dollar IEMs.  :banghead:

I believe that bozo was me, but to be fair I did preface the statement with 'for sensitive IEMs'.
Mine are 124dB/mW and 46Ω. To get 115dB from a .5V source (say my Clip+) I need a gain of .2x , or 1/5th.
If your IEMs happen to need more than what you specified from Oliver, you only have your own lazyness to blame.

 

[Br777]

Quote:

I believe that bozo was me, but to be fair I did preface the statement with 'for sensitive IEMs'.
Mine are 124dB/mW and 46Ω. To get 115dB from a .5V source (say my Clip+) I need a gain of .2x , or 1/5th.
If your IEMs happen to need more than what you specified from Oliver, you only have your own lazyness to blame.

 
funny, we both thought he was talking about us, and we both gave the same answer

 

[limpidglitch]

Quote:

 
funny, we both thought he was talking about us, and we both gave the same answer

Hah!
Apparantly the world is full of bozos like us

 

[khaos974]

Quote:

Quote:

I don't think that the gain structure of the O2 allows the potentiometer to clip the signal, I actually see no reason why the it shouldn't be used at 3 o'clock or even fully turned.

 
Can't the 4556s can run out of current and clip into loads less than 50 or so ohms?
 
Also even from a source with a volume control, I wouldn't run any amp this strong at max volume like that unless you only ever have really inefficient headphones hooked up to it.  One click or pop from your source could ruin some pretty expensive headphones and give you a very unpleasant ringing in your ears.

Sorry, I was rather imprecise, I meant clipping  hitting the voltage rails, yes, running out of current is quite possible, but not with any normal IEMs,
 
@estreeter, I just checked the RE262 specs, 150 ohms and what I assume is 95 dB/mW (since the other HifiMan are rated in dB/mW), WOW! That's 103 dB/V compared to 105 dB/V for the K701.
The Re262 need a higher voltage swing than the K701.

 

[maverickronin]

Quote:

Mine are 124dB/mW and 46Ω. To get 115dB from a .5V source (say my Clip+) I need a gain of .2x , or 1/5th.

Wow.  These IEMs are seriously getting out of hand...
 
At this rate induction is going to let you detect oscillating magnetic fields with IEMs just by walking around with them.

 

[estreeter]

Guys, I did omit some important info from my earlier post.
 
1. Yes, using the line-out from my T51 or the RCA-to-mini from my HRT MSII *does* improve things, but its more pronounced with my other portables.
 
2. I agree that specifying my gain settings improperly did come down to my own laziness, but I had just been bitten by the ZO2V1, where the default gain was ridiculously high and I couldnt use the line-out from *anything*
 
If I can be more specific, using the same source/phones, I can get the same overall volume at about 10am on the uHA-120, and taking it past 'midday' would be a bad idea for my longterm hearing. When I had the P4, I rarely had to take it beyond 9am. 
 
I will also add that the EHP-02 has channel imbalance at low volumes, but its at lower volumes than I would ever listen to music. I have been assured that this is merely imbalance in the 'gang pot', whatever that is, and I only need to cut a single connection to remove the 'low gain' multiplier and the problem will disappear. Given that I dont like '2x', I'm unlikely to go with '1x' .......

 

[khaos974]

FWIW, the optimal zone of a pot is usually beyond 11 am and the UHA-120 has a gain of 4X.

 

[zzffnn]

II would like to add that my O2 amp has also served me very well as a pre-amplifier. Transparent, enough gain (even from iPhone 3GS' HO) and volume control. Zero noise.

 

[Willakan]

Just to confuse the matter further, I am driving the K702s and find they get plenty loud with unity gain. At 3.5X gain my listening level is sitting firmly in the realm of channel imbalance. I do have a slightly hot source though (2.1V) and I tend to listen in quiet places, quietly. Took my Grados in a car once: had to boost the volume of my player by about 10db just to hear the music quietly over the engine noise.