[Twinster]

Hi Naim.F.C,  how do you like the T1 with the O2?  Do you have to use the High gain (6.5x) on the O2 and where is the volume position at normal listening level?
 
I'm asking because I'm waiting for my T1 now and just build my O2 last week and I'm hoping to be able to pair them.  My O2 have the gain set to 1x & 3x.  I may have to increase the high gain.
 
 
Quote:

Just to chime in and say I have exactly the same issue, round about the same 3:00 mark too with the T1's. Maybe actually just under. Before that threshold, it's amazing, detailed, sharp, punctual and amazingly revealing (lacking in sub bass a touch though, and perhaps a little too energetic at top, but only ever so slightly). But past that point? Sibilance starts rearing its ugly head, barging other sounds out the way and essentially forcing me to tone down the volume.
 
Shrill is exactly how I'd describe it too.
 
In a way it's good because I hate when I sometimes creep up to this stupidly high volume, but also weird that it happens. I don't have this same level of sibilance, or such a point of immediate sharpness with my other amps, as I do the O2. Wonder what the reason could be for it?
 


 

 
 

 

[Twinster]

Hey Wayne,  be sure to measure the voltage out of your new adapter because 13 volt might not be enough.
 
Nwavguy explain it in the "Using the O2, Power jack" section. The O2 expect at least 14 volts and not more then 20. The 12 volt 200 mah from the BOM is actually putting out about 14 volts as per NwAvGuy. Also it need at least 200 mah min.
 
To be safe I went with the 16 volts 400 mah like many other did.
 
 
Quote:

My Triad power adapter died after 2 months this past weekend.  I've never kept it plugged into a socket for more than 8 hours.  I'd move the amp around, so it would have time to cool, etc.  I did find an adapter at Radio Shack that is adjustable from 9V AC to 13V AC.  The end plug was the same size as that on the O2 amp, so no additional modifications were needed.  However, Radio Shack does charge $22.99 for the adapter, plus tax.

 
 

 

[upstateguy]

Quote:

You know, I think I have another idea about what's up with USG's O2.
 
The O2 has no charging indicator so if the AC was plugged in but not making contact for some reason you wouldn't know apart from testing for the clipping point.  If you keep using it like that the battery will run down and the clipping point will get lower and lower making the sound worse.  If after a few cycles of plugging and unplugging it finally does make contact it will charge, run off the rails you expect, and the problem will go away.
 
On battery power 4.5/gain give you the maximum input before clipping and 4.5/2.5 = 1.8 which would make a 2V input clip.  On stuff with a decent amount of dynamic range it might even end up being pretty subtle and only obvious at higher volumes.
 
I'm not sure that this really explains everything that USG said he heard but I don't really know how else it could have got better over time.

No batteries installed.  Don't know if that makes a difference.
 

 

[maverickronin]

Quote:

No batteries installed.  Don't know if that makes a difference.

You don't have any batteries in it?
 
Well my idea is shot then.  If it wasn't making contact like I was guessing then it wouldn't play at all because it would have no power.

 

[Naim.F.C]

I thoroughly enjoy them. In-fact, I don't currently have an amp that retrieves more detail from my music than with the O2. It is incredibly revealing. Only downside is it is a tiny bit harsher or sharper sounding than other amps I've tested. On rare occasion you can come across sibilance on certain tracks but only listening at high volumes. Don't get me wrong, it's not artificial or narrow sounding, it's still very natural and realistic, just has a teeny bit of edge sharpness at higher volumes.
 
I do miss the warmth of the Continental somewhat (trust me it's not placebo, the difference is there), but I can definitely hear more micro details using the O2. So it's a trade off with some mellowness in place of intricacy and outright detail. Soundstage wise they are the same, which is great as the soundstage on the ALO is greater than the cMoyBB, Pico and SR-71A, and about on par with my old Concerto.
 
My V200 should be with me this week so I'll compare the O2 with that as well. Clash of the titans really. One pushing the high value stakes, the other mid-fi.
 
Volume wise, I actually use both the LCD-2 and T1 on low gain (with AC plugged in). Haven't really tested it much on battery. But on low gain, with the AC in, with the T1's on average I'm listening to them at around the 11 to 2:30 position, and with the LCD-2's around 1 to 4pm. T1's tend to favour low-mid volume listening, and the LCD-2's mid-high. High not being recommended, unless you want to lose the quality of your hearing over time.
 
Quote:

Hi Naim.F.C,  how do you like the T1 with the O2?  Do you have to use the High gain (6.5x) on the O2 and where is the volume position at normal listening level?
 
I'm asking because I'm waiting for my T1 now and just build my O2 last week and I'm hoping to be able to pair them.  My O2 have the gain set to 1x & 3x.  I may have to increase the high gain.
 
 


 
 

 

 

[sphinxvc]

Quote:

Only downside is it is a tiny bit harsher or sharper sounding than other amps I've tested. On rare occasion you can come across sibilance on certain tracks but only listening at high volumes. Don't get me wrong, it's not artificial or narrow sounding, it's still very natural and realistic, just has a teeny bit of edge sharpness at higher volumes.

 
Are the other amps you've tested softer?  I find just a bit of harshness & sharpness in every T1 I've heard.  

 

[kyoshiro]

i've also noticed that 1 night of charging cant charge 2 200mah nimh 9vs fully with a 20VAC 1000ma charger 
I only got like 6~7 hrs of play time then shut down mode
sooo I went and bought a Powerex charger which should hopefully allow me to get the full 10 expected hrs

 

[mikeaj]

 
Quote:

i've also noticed that 1 night of charging cant charge 2 200mah nimh 9vs fully with a 20VAC 1000ma charger 
I only got like 6~7 hrs of play time then shut down mode
sooo I went and bought a Powerex charger which should hopefully allow me to get the full 10 expected hrs

Wait, you sure about this, or don't you think you might be drawing the wrong conclusion?  6-7 hours runtime is normal for a couple of 200 mAh batteries.  Why and how would one charger not be able to charge them to capacity, while another one can?
 
Anyway, what were the battery voltages after charging and then in shutdown mode?  For many models there should be some kind of capacity vs. voltage curve you can look at.

 

[wje]

Quote:

Hey Wayne,  be sure to measure the voltage out of your new adapter because 13 volt might not be enough.
 
Nwavguy explain it in the "Using the O2, Power jack" section. The O2 expect at least 14 volts and not more then 20. The 12 volt 200 mah from the BOM is actually putting out about 14 volts as per NwAvGuy. Also it need at least 200 mah min.
 
To be safe I went with the 16 volts 400 mah like many other did.
 

Simon,
 
Thanks.  I wasn't aware of that much variance that would be allowed / tolerated.  However, it is good to know.  The replacement adapter I purchased from Radio Shack is adjustable up to 13VAC with 800mA.  It seems as though I might be able to step up to the next level of power supply and set it in the 18V or so range.
 
The Triads are quite cheap from the vendors that sell electronic components - usually a little under $6.00 (US $$.)   However, I think with so many O2 amps being built, most vendors are either in a low stock situation or out of stock for a month or so for that particular power adapter.  The only thing that rubbed me on the R.S. adapter was spending nearly $27.00 on it, including taxes.  There is a 30-day return policy, though, if I can locate something else.
 

 
 

 

[kyoshiro]

Quote:

 

Wait, you sure about this, or don't you think you might be drawing the wrong conclusion?  6-7 hours runtime is normal for a couple of 200 mAh batteries.  Why and how would one charger not be able to charge them to capacity, while another one can?
 
Anyway, what were the battery voltages after charging and then in shutdown mode?  For many models there should be some kind of capacity vs. voltage curve you can look at.

Sorry should have said the AC 20VAC 1000mah wall adapter using the internal charging circuitry. But yeah I was actually expecting more hours with these 200mah  
and i was referring to amount charged in the same amount of time. 
As for battery voltage, I'll get it to shut down again tmr and have a test, didnt have a multimeter with me @ work 
Also not having a charge indicator does create a few problems with not knowing when the battery is charged or not. 
Am charging my 200mah GP 8.4V with my powerex charger, the imedions 9.6v charged in like an hr or so, these are still charging, prob cuz the 90ma isnt enough to kick it into rapid charge mode or something (it needs 100ma+)

 

[Willakan]

Wow: NwAvGuy has just revealed the board for 24/96 USB DAC capability will fit inside the existing O2 in the space otherwise occupied by the batteries. I find the idea of a tiny yet completely transparent signal chain quite appealing: USB cable goes in, sound for my headphones come out, all in a relatively tiny box (It will all fit in the smaller of the O2 enclosures apparently).
 
And he bought a new scope to peer at I2S streams

 
 

 

[DarknightDK]

Saw that too. Looks like the this is going to be one hell of a portable source / amp combo.

 

[Maxvla]

Well if it's instead of batteries, it's no longer portable (for anyone) but truly transportable.

 

[Draygonn]

Am I correct in thinking If you are using USB input for the DAC you can't hook it to any DAPs anyway so the batteries would be moot?

 

[Maxvla]

Didn't look at the DAC, but I guess you are right. If it were a spdif input it could, but battery life would be even shorter.