[oyster]

Quote:

 
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.

 
I use a 93db 150ohm Yamaha.
I have a few questions-
a) Higher power supply results in higher loudness?
b) Higher power supply would positively affect bass? ( I may be totally wrong but i think low frequencies require good amount of power to avoid clipping, better control/impact etc..)
c) Would switching to 18/20 v from 13v make any/even marginal difference or that 5/7v difference is too small to consider in such a circuit ?

 

[maverickronin]

Quote:

I use a 93db 150ohm Yamaha.
I have a few questions-
a) Higher power supply results in higher loudness?
b) Higher power supply would positively affect bass? ( I may be totally wrong but i think low frequencies require good amount of power to avoid clipping, better control/impact etc..)
c) Would switching to 18/20 v from 13v make any/even marginal difference or that 5/7v difference is too small to consider in such a circuit ?

 
a) Not really.  The gain is the same either way and if the power supply rails are too low for the configured gain the input stage will clip regardless of where the volume control is set.  The internal regulation steps it all down to 12v (IIRC) anyway.  It just turns the extra voltage into current in case the output opamps need it.
 
b) It might if you were using a lower impedance 'phone.  Those Yamaha's aren't super efficient but they need more voltage than current.  Even at full 7vrms output they shouldn't draw enough current to make the onboard regulators fall out of regulation, give noisy power to the opamps, and add distortion to what you hear.
 
c) It shouldn't matter with your current headphones.  If you were using an HE-5 or HE-5LE or some other inefficient and low impedance ortho then it would be worth a try.
 
Of course all that assumes the transformer you're using now is working in proper spec.  If you think you're hearing something odd it might be worth it to try out a different one just to see if the one you have is busted or rated higher than its actual capabilities.

 

[evanft]

I can confirm that the default low gain setting of 2.5 is not good enough for the DT880 600 ohm.

 

[maverickronin]

Quote:

I can confirm that the default low gain setting of 2.5 is not good enough for the DT880 600 ohm.

 
What your source's output level?

 

[evanft]

Quote:

 
What your source's output level?

 2 V from the ODAC. I have to turn it all the way up for anything that isn't really loud, like modern compressed stuff. If something's quiet, like classical or older recordings, I can't get it to a satisfying volume.

 

[maverickronin]

Quote:

 2 V from the ODAC. I have to turn it all the way up for anything that isn't really loud, like modern compressed stuff. If something's quiet, like classical or older recordings, I can't get it to a satisfying volume.

 
That's 5V RMS output and 110dB peaks calculated from the pair that Tyll measured.
 
Assuming you're not killing the headroom with DSPs or EQ you should probably turn it down to save your hearing...

 

[evanft]

Quote:

 
That's 5V RMS output and 110dB peaks calculated from the pair that Tyll measured.
 
Assuming you're not killing the headroom with DSPs or EQ you should probably turn it down to save your hearing...

Like I said, some music is ok, but quieter recordings are not. I would say a large portion of my collection is within listenable levels or just barely, but older CDs and classical music will not reach desired levels. Death Magnetic, and a lot of modern metal, for example, is fine, though I am at about 3/4 of the dial, maybe slightly less.
 
The builder mistakenly made my gain levels 2.5/6.5 instead of 2/3 or 2.5/3.5. But, he used jumpers on the resistors so they can easily be replaced, so it's no big deal.
 
It sounds great, though. The whole point is somewhat moot since I'm upgrading to the HE-500, which apparently need less than 2.5x gain.

 

[maverickronin]

Quote:

Like I said, some music is ok, but quieter recordings are not. I would say a large portion of my collection is within listenable levels or just barely, but older CDs and classical music will not reach desired levels. Death Magnetic, and a lot of modern metal, for example, is fine, though I am at about 3/4 of the dial, maybe slightly less.
 
The builder mistakenly made my gain levels 2.5/6.5 instead of 2/3 or 2.5/3.5. But, he used jumpers on the resistors so they can easily be replaced, so it's no big deal.
 
It sounds great, though. The whole point is somewhat moot since I'm upgrading to the HE-500, which apparently need less than 2.5x gain.

 
I get that you're talking about better recorded stuff have more dynamic range and needing a higher output because the average level is lower but your average listing level still seems pretty high.
 
I haven't owned the 880/600s but I did have the 770/600s and the 990/600s and used them with the Total BitHead I had at the time I thought they got plenty loud for modern more compressed music and were only a little quiet with HDR classical and jazz from probably around a 1/5 of the voltage of the O2.  I know my average listening level is kinda low but there's probably middle ground somewhere so I don't know how many other people would have volume issues either.

 

[mac336]

does anyone know when you know who expects to complete designs for the ODA and how exactly is the ODA supposed to change or improve from the O2?
 

 

[alphaphoenix]

^????

 

[Phos]

Quote:

does anyone know when you know who expects to complete designs for the ODA and how exactly is the ODA supposed to change or improve from the O2?
 

I don't know anything I haven't read off his blog but apparently the power supply will be improved.  

 

[khaos974]

Quote:

does anyone know when you know who expects to complete designs for the ODA and how exactly is the ODA supposed to change or improve from the O2?
 

 
The gain structure is supposed to be reworked so as to avoid the most egregious issues with mismatched gain,

 

[stv014]

Currently, it looks like the ODA will not be available before the end of the summer, perhaps even later.
I think the change to the gain selection will be simply the addition of a third setting. The basic design of a gain stage followed by the volume control and a unity gain buffer (parallel NJM4556's) will probably not be modified.

 

[placebo-fi]

The actually helpful O2 thread needs more love.

 

[sling5s]

I just got the O2+ODAC.  I could not resist the price and hype.
 
First, I was expecting something bigger.  It's so small.  Yet, it has a big sound. It really sounds like a desktop amp.
Second, I was expecting bright and lean.  But it's smooth, clean and not lean at all.  Nice bass. Not something you get for something that resembles a portable amp. Really pleasantly surprised.
 
I tried my JH13pro.  Wow.  Nice and smooth.  Not edgy or hot like I expected.  The bass finally came alive, something that only happens with a good desktop amp on these.
I tried the Grado Magnums.  It of course did not warm it up but it did not accentuate it either.  It sounded smooth.  
I tried last my LCD-2 r.1.  It no longer sounded warm and creamy.  It sounded very neutral for the first time.  At least to me.
 
But overall. I am very pleasantly happy.  I could not ask for more for such a low price and size.  Very powerful transportable, amp/dac combo that more than satisfies.
 
edit: I still think the LCD-2 needs more power.  This little thing is really powerful for what it is, but I think the LCD-2 needs more to sound full and alive.