[diamondears]

45 mW --> 100 dB
141 mW --> 105 dB
447 mW --> 110 dB
794 mW --> 112.5 dB
1413 mW --> 115 dB

P = [(VRMS)^2 / Z]
VRMS = (P*Z)^0.5
Where: Z = headphone impedance in ohms, P = output power in mW


See also:
https://docs.google.com/a/jdslabs.com/spreadsheets/d/1****TwWffXKld7PgHt5wZOP7KnBVO6SyvG9yZEJ-smI/edit#gid=1006269980

So 7Vrms clipping point would come up to how many dB?

 

[headwhacker]

So 7Vrms clipping point would come up to how many dB?

 
O2 will start to clip around 6.8 Vrms. Theoretically O2 can only drive HE-6 at 113dB max.

 

[jseaber]

So 7Vrms clipping point would come up to how many dB?

 
Clipping should occur close to 110dB listening volume. It's easy to refer to an SPL chart. 
 
Slightly off topic: Peak output from O2 is 7.55VRMS for 150+ ohm loads. I need to verify how NwAvGuy arrived at the 7.0VRMS limit. It may be a conservative rounding error. Or a real input limit. Poke me if this isn't answered this week!
 
Edit: Sorry for the repeat posts, headwacker. I'll sign off.

 

[diamondears]

O2 will start to clip around 6.8 Vrms. Theoretically O2 can only drive HE-6 at 113dB max.

113dB is very loud sir! 113dB isn't enough on your classical music you mentioned?

Clipping should occur close to 110dB listening volume. It's easy to refer to an SPL chart. 

Peak output from O2 is 7.55VRMS. I need to verify how NwAvGuy arrived at the 7.0VRMS limit. It may be a conservative rounding error. Or a real input limit. Poke me if this isn't answered this week!

Edit: Sorry for the repeat posts, headwacker. I'll sign off.

110dB is good enough for me! And that's the extreme hungry power HE-6. Don't understand the talk about O2 lacking power.

 

[headwhacker]

   
Clipping should occur close to 110dB listening volume. It's easy to refer to an SPL chart. 
 
Peak output from O2 is 7.55VRMS. I need to verify how NwAvGuy arrived at the 7.0VRMS limit. It may be a conservative rounding error. Or a real input limit. Poke me if this isn't answered this week!
 
Edit: Sorry for the repeat posts, headwacker. I'll sign off.

 
No harm done John. Your post is just as important and informative. I think Nwayguy just use 7Vrms as a conservative limit but O2's measured peak is well beyond 7Vrms. I think it's 7.3Vrms if you extrapolate it from his published measurements at 150 and 600 Ohm load. 

 

[headwhacker]

113dB is very loud sir! 113dB isn't enough on your classical music you mentioned?
110dB is good enough for me! And that's the extreme hungry power HE-6. Don't understand the talk about O2 lacking power.

 
113dB is an ideal level. Usually you have 1 to 3dB margin of error. So John's estimate of 110dB represents real world usage scenario. That is why I always add 3dB on top of my target SPL when looking for an amp.
 
Try it first so you can see why. Classical music has lots of peaks and and silent passages. And the difference between the silent and the loudest level is around 20dB to 30 dB. Modern pop/rock songs (highly compressed) would work and enough for HE-6 driven by O2.  

 

[diamondears]

Not the widest DR but try the album Tchaikovsky: The Nutcracker. I think it is the 2011 remaster.

Thanks

What record label?

 

[Tostitostelli]

JDS Lab ODAC usb DAC + JDS Lab O 2 head amp full modification with Black Gate Capasitors

I has to know where that awesome case comes from! Or has you made it yourself? *k back to normal english*

 

[HotIce]

 
Clipping should occur close to 110dB listening volume. It's easy to refer to an SPL chart. 
 
Slightly off topic: Peak output from O2 is 7.55VRMS for 150+ ohm loads. I need to verify how NwAvGuy arrived at the 7.0VRMS limit. It may be a conservative rounding error. Or a real input limit. Poke me if this isn't answered this week!
 
Edit: Sorry for the repeat posts, headwacker. I'll sign off.

 

7.55V RMS at clip, or with THD under 0.1%?
With 12V Rail, and tossing about 0.35V on the schottky diode (D1/D5), leaves 11.65V to the OP-amp.
7.55V RMS is 10.68V peak, which leave less than 1V to be shared between the Vce of the VAS BJT, and the Vbe of the driver.
Given the Vbe of the driver around/at-least 0.65V, leaves less than 0.35V for the Vce of the VAS BJTs, and BJTs really do not like to work in that area, in the analog space.

 

[Smugsie]

Can someone explain a bit how well the ODAC scales up to higher grade DAC's? How much would I have to spend to get a decent upgrade out of the ODAC loop?

 

[Solrighal]

  Can someone explain a bit how well the ODAC scales up to higher grade DAC's? How much would I have to spend to get a decent upgrade out of the ODAC loop?

 
+1 I'd also like to know where to go next.

 

[Rajikaru]

  Can someone explain a bit how well the ODAC scales up to higher grade DAC's? How much would I have to spend to get a decent upgrade out of the ODAC loop?

 
First, you need to come up with a  definition for  'higher grade DAC'.
 
Other than that, the answer depends on the game master of whichever fantasy role play you subscribe to. 
 
In other words, outside of objective parameters, everything is intangible, unverifiable, and subjective.  

 

[Tostitostelli]

  Can someone explain a bit how well the ODAC scales up to higher grade DAC's? How much would I have to spend to get a decent upgrade out of the ODAC loop?

Well I've read and seen allot of reviews where the ODAC is portrayed as ''punching above its weight''. I personally wouldnt know, but if any DAC can, the ODAC can.

 

[Smugsie]

   
First, you need to come up with a  definition for  'higher grade DAC'.
 
Other than that, the answer depends on the game master of whichever fantasy role play you subscribe to. 
 
In other words, outside of objective parameters, everything is intangible, unverifiable, and subjective.  

 
I was going to type out paragraphs, but I'm going to throw that out the window.
 
If I spent $350 on a DAC like a Little Dot DAC_I or Schiit Bitfrost, would I hear an upgraded difference other than coloration? Such as more detail retrieval and the "speed of sine waves" (for lack of a better term), because from what my understanding is; there is a loss of 1's and 0's from a digital signal to an analogue signal.
I can only assume that paying more money for a DAC means better engineered DAC's that converts the 1's and 0's to just 1's and 0's instead of half a 1 and sometimes no 0.
Right now I'm going for a Little Dot Mk.3 amp, and I'm wondering if there would be any reason to upgrade from the ODAC.

Edit: I'm not here to prove a point, I'm just here to ask for opinions on whether or not it's worth to spend the extra money to upgrade from the ODAC. Just purely based on experience. I know how subjective audio can get and I'm not here to start another sound science debate.

P.S. the headphone I'm using is an AKG Q701.

 

[diamondears]

I was going to type out paragraphs, but I'm going to throw that out the window.

If I spent $350 on a DAC like a Little Dot DAC_I or Schiit Bitfrost, would I hear an upgraded difference other than coloration? Such as more detail retrieval and the "speed of sine waves" (for lack of a better term), because from what my understanding is; there is a loss of 1's and 0's from a digital signal to an analogue signal.

I can only assume that paying more money for a DAC means better engineered DAC's that converts the 1's and 0's to just 1's and 0's instead of half a 1 and sometimes no 0.

Right now I'm going for a Little Dot Mk.3 amp, and I'm wondering if there would be any reason to upgrade from the ODAC.


Edit: I'm not here to prove a point, I'm just here to ask for opinions on whether or not it's worth to spend the extra money to upgrade from the ODAC. Just purely based on experience. I know how subjective audio can get and I'm not here to start another sound science debate.


P.S. the headphone I'm using is an AKG Q701.

I'm just gonna roll with that and "save" money for my amp.

Thanks for the share.

I suggest you invest in a DAC and just buy a transparent amp like the O2--as transparent as a wire with gain.

Problem with people saying "all DACs are the same" is that they're comparing DACs with the SAME digital filter (most common is standard/linear filter). IME, they would all sound the same. So when you look for a DAC, one should look at the digital filter or filters used.

Some filters have pre-ringing, post-ringing, rolls off the high frequency slower/faster/suddenly/earlier/later, and some has different amounts of timing phase delays. All these affect the SQ. Now if you're told that a certain DAC sounds better and because of it it's much more pricey, but it has a same standard linear filter as that of the ODAC, IME you're being snake oiled. But if the filters arent the same, look at the implementation of the filters as one could have pre-ringing and later rolling off but faster/sudden rolling off, while the other have no pre-ringing and earlier rolling off but slower. These two filters would sound dramatically different, unless the implementation were designed to offset their peculiar characteristics and they eventually ended up sounding the same.

As usual, my honest advise is invest in a DAC with several digital filters to choose and good implementation. Then just get a transparent amp that would just "transport" the sound from the DAC.

My honest 2 cents.