[LizardKing1]

I guess you're right, it doesn't make much sense.
In any case, when equalizing it's always preferable to decrease than to increase, because even though you get 'less bits' you also get less distortion and at least to me the increase in distortion ruins music more than the decrease in digital information.

 

[haejuk]

I will try with no EQ when I get home today.  I find it very likely that the volume attenuation is saving me from clipping with the iPod.  The signal I sent from my DAC was not attenuated by any volume control, software or hardware, before reaching the amp.  I tried the exact same source material and got much worse results with the iPod, so I guess I should have enough info to figure this out now.  Thanks for the help guys, I am sure I will work it out soon enough.

 

[haejuk]

Just for closure:
I had a bad iPod LOD cable that was causing my problems.  Just finished making my own and it sounds fine now.
 
Still surprised by the O2's performance.  And totally black background even with my super sensitive IEMs.

 

[evanft]

Question.
 
My current headphones are Beyer DT880 600 ohms. I used a calculator that someone posted here a while ago and figured out that the gain for the O2 should be 3.2 to get 115 dB. Is this enough to cause clipping? I'll probably have it set by the builder at 2x/3x, since some of the headphones I'm looking to upgrade to seem to be right around the 2x gain range.
 
EDIT: I'm actually pondering an ODAC/O2 combo now. Apparently the ODAC is outputting 2.0 Vrms, so I need gain of 2.5/3.5.

 

[imackler]

Quote:

Question.
 
My current headphones are Beyer DT880 600 ohms. I used a calculator that someone posted here a while ago and figured out that the gain for the O2 should be 3.2 to get 115 dB. Is this enough to cause clipping? I'll probably have it set by the builder at 2x/3x, since some of the headphones I'm looking to upgrade to seem to be right around the 2x gain range.
 
EDIT: I'm actually pondering an ODAC/O2 combo now. Apparently the ODAC is outputting 2.0 Vrms, so I need gain of 2.5/3.5.

Where is that calculator at? 

 

[evanft]

Quote:

Where is that calculator at? 

https://docs.google.com/spreadsheet/ccc?key=0ApXAMJq3BUqQdERDZTU3Z1JiYmZwRzRoN01pQWN5cVE

 

[stv014]

Quote:

Originally Posted by evanft /img/forum/go_quote.gif
 
My current headphones are Beyer DT880 600 ohms. I used a calculator that someone posted here a while ago and figured out that the gain for the O2 should be 3.2 to get 115 dB. Is this enough to cause clipping? I'll probably have it set by the builder at 2x/3x, since some of the headphones I'm looking to upgrade to seem to be right around the 2x gain range.
 
EDIT: I'm actually pondering an ODAC/O2 combo now. Apparently the ODAC is outputting 2.0 Vrms, so I need gain of 2.5/3.5.

 
A 7 Vrms level is very close to clipping, it would be safer to use the default 2.5x gain only, unless you really need 115 dB SPL (something I would not recommend for regular listening).
 

 

[Phos]

Does the Gamma2 actually hit 2V RMS?

 

[mikeaj]

Quote:

Does the Gamma2 actually hit 2V RMS?

 
AMB's site says 1.4V rms for full-scale output.  I think I read that before elsewhere as well.
http://www.amb.org/audio/gamma2/
 
Did you post this question in the right thread?  Well anyway, that's that.

 

[Phos]

Quote:

 
AMB's site says 1.4V rms for full-scale output.  I think I read that before elsewhere as well.
http://www.amb.org/audio/gamma2/
 
Did you post this question in the right thread?  Well anyway, that's that.

Yeah, I noticed that evanft's spread sheet had its output set at 2 V RMS.  
 
Edit: 2.2 V actually.  

 

[evanft]

Quote:

Yeah, I noticed that evanft's spread sheet had its output set at 2 V RMS.  
 
Edit: 2.2 V actually.  

 
Whoever I got the spreadsheet from had used it for the Gamma 2. I just never bothered to change it. I just mess with the output V when I need to.
 
 
 

 
A 7 Vrms level is very close to clipping, it would be safer to use the default 2.5x gain only, unless you really need 115 dB SPL (something I would not recommend for regular listening).
 

 

 
I actually just ordered a ODAC/O2 combo. I went with 2.5/3.5. As you said, 3.5 puts me right below clipping, but it should be fine. If it gives me problems, I'll just swap out resistors.

 

[stv014]

Quote:

I actually just ordered a ODAC/O2 combo. I went with 2.5/3.5. As you said, 3.5 puts me right below clipping, but it should be fine. If it gives me problems, I'll just swap out resistors.

 
3.5x gain with 2.2 Vrms input voltage would definitely clip with a 0 dBFS digital signal. The 2.5x gain should be fine, and likely still plenty loud enough anyway.

 

[evanft]

Quote:

 
3.5x gain with 2.2 Vrms input voltage would definitely clip with a 0 dBFS digital signal. The 2.5x gain should be fine, and likely still plenty loud enough anyway.

 
The ODAC outputs 2.03 Vrms. I had calculated my gains with 2 Vrms. I'll change them to 2x/3x instead to give myself a little safety margin.

 

[oyster]

Has anybody tried swapping AC power supplies with O2? Like performance difference at varying voltage......14v-20v. I am currently using 13v AC. Would a higher power supply like say ...18V benefit?

 

[maverickronin]

Quote:

Has anybody tried swapping AC power supplies with O2? Like performance difference at varying voltage......14v-20v. I am currently using 13v AC. Would a higher power supply like say ...18V benefit?

 
On paper the only benefit you'd get from a higher voltage transformer would be when listening to low impedance 'phones at high levels.  It would keep the power supply from falling out of regulation when the output opamps were drawing lots of power.