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O2 AMP + ODAC - Page 15

post #211 of 3453

7.3 volts at 600 Ohms....

 

Should do just fine..

 

Alex

post #212 of 3453
Quote:
Originally Posted by adydula View Post

7.3 volts at 600 Ohms....

 

Should do just fine..

 

Alex

 

Do you mind explaining how you got to that number? I'd love to be able to figure it out for myself in the future. Thanks :)

post #213 of 3453
Quote:
Originally Posted by Bojamijams View Post

Do you mind explaining how you got to that number? I'd love to be able to figure it out for myself in the future. Thanks :)

 

It is in the "O2 Headphone Amp" blog article of the designer, which is not allowed to be linked here. Check the "THD+N vs OUTPUT & MAX POWER ON AC" graph. Note however, that the 7.3 Vrms level is measured at 1% THD, it is at slightly less than 7 V where the distortion starts to rise due to clipping. Also, to get that high voltage out of the amplifier, you need to either set the gain accurately (using custom resistor values), or use high gain and control the volume at the source. In any case, the 5 Vrms output from a standard 2 V source and 2.5x default low gain should be enough for most people. It is also about the maximum you can get on battery power.

post #214 of 3453

I would be getting the amp with a 1x/6.5x gain switch (so that it can drive my JH|13's as well as the DT-800/600)

 

The source would be the TC 750 preamp (boosting a TT phono signal). Not sure on its output voltage.

 

I'll order the AC cord from JDS as well just in case the battery can't get there (but I think it probably would be able to)

post #215 of 3453
Quote:

Originally Posted by Bojamijams View Post

 

The source would be the TC 750 preamp (boosting a TT phono signal). Not sure on its output voltage.

 

It has a gain of 40 dB, and a nominal output voltage of 300 mV, but it depends on the input voltage received from the source.

post #216 of 3453

Interesting, thank you for looking that up! :)

 

I think I'll get the O2 with a 1.0/6.5x (max low/high basically) and that should give me the power to get the DT880 to proper volume.

post #217 of 3453

just want to know how good is the Dac compared with more expensive, full size ones.

post #218 of 3453
hey guys, anyone here using e-mu 0404 usb? i was wondering how it compares to the odac-o2 combo, as dac+preamp? i'm planning to switch from my emu, so i'm collecting some info.
post #219 of 3453

safer,

 

You can find the designers site easily on the net...and read about his and in the comments / blog there are several comments on dac comparisons.

 

I have compared with several, HRT MSii+ USB , ESS Sabre Dacs in a high end source, there is no real detectable differences to my ears with cans or speakers IMO.

 

This is a great dac and compares very well with many others priced much higher....

 

I am sure others will chime in..

 

Alex

post #220 of 3453

thanks for the help. I will try to get one from the forum.

post #221 of 3453
Quote:
Originally Posted by adydula View Post

safer,

You can find the designers site easily on the net...and read about his and in the comments / blog there are several comments on dac comparisons.

I have compared with several, HRT MSii+ USB , ESS Sabre Dacs in a high end source, there is no real detectable differences to my ears with cans or speakers IMO.

This is a great dac and compares very well with many others priced much higher....

I am sure others will chime in..

Alex
I'll second that.
post #222 of 3453

Using the combo of JDS ODAC and a DIY Desktop style version of O2 (with RCA's, 1/4 plug)... man... the HD800's sound excellent through them!  

post #223 of 3453

What's the output power of O2? I'm thinking of getting it to replace the trusty E17 in driving my HE400s.

post #224 of 3453
Quote:
Originally Posted by jerg View Post

What's the output power of O2? I'm thinking of getting it to replace the trusty E17 in driving my HE400s.

 

On battery, something like 534mW (4.2V) into 33 ohms, 338mW (5.2V) into 80 ohms.  So for ~50 ohms HE-400, maybe something around 500mW (5V), definitely not shy of 350mW.  That's the advantage of packing two 9V batteries.

 

But to reach that level without clipping the input, you need to be careful about getting the correct gain, given whatever source you're using.  Then again, you really don't want to be pumping 500mW into HE-400 and having that placed on somebody's head.

post #225 of 3453
Quote:
Originally Posted by mikeaj View Post

 

On battery, something like 534mW (4.2V) into 33 ohms, 338mW (5.2V) into 80 ohms.  So for ~50 ohms HE-400, maybe something around 500mW (5V), definitely not shy of 350mW.  That's the advantage of packing two 9V batteries.

 

But to reach that level without clipping the input, you need to be careful about getting the correct gain, given whatever source you're using.  Then again, you really don't want to be pumping 500mW into HE-400 and having that placed on somebody's head.

 

I'm thinking of the O2D combo that's built into the O2 casing. The ongoing zeitgeist with planar magnetic cans seems to be that they shine with oodles of high quality power fed into them, and I just wonder if O2 would be up for that or if I should look farther.

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