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Next step up from ODAC? - Page 3

post #31 of 41

I'm also one considering to "potentially" upgrade my ODAC sometime along the future.

 

My current setup is an ODAC + O2 combo, with HD650's

 

The questions I have however, arises from my absolute inability to detect any sort of "noise" from the system. Which means (to me) it's clean enough for my enjoyment. If we remove "reduction of noise" out of the equation, then what sort of improvements could I notice from using devices such as the iFi iUSB?

 

If the changes are too little to even consider, would it be better to just save up for a Bifrost Uber Gen 2 USB DAC?

 

My decisions and questions come from reading this FlySweep's post: http://www.head-fi.org/t/661444/schiit-bifrost-uber-analog-upgrade/390#post_9704321 , which also includes the BH Crack, something in which I am going to save up for.

 

*Edit: I'm also going to include the Aqvox USB Low-Noise Power Supply in this question, which seems to be nearly half the price of the iFi iUSB*


Edited by JacobLee89 - 1/28/14 at 3:21pm
post #32 of 41

ISTM by removing 'reduction of noise' from the equation you have removed all possibility of better sounding kit. All improvements I've made to my designs (DACs and amps) have been down to reductions of noise. Not the noise that's present with no signal playing, rather the noise that comes from IMD and below-optimal PSRR in DACs and amps when music's being reprotuced.

post #33 of 41
Quote:
Originally Posted by Sapientiam View Post
 

ISTM by removing 'reduction of noise' from the equation you have removed all possibility of better sounding kit. All improvements I've made to my designs (DACs and amps) have been down to reductions of noise. Not the noise that's present with no signal playing, rather the noise that comes from IMD and below-optimal PSRR in DACs and amps when music's being reprotuced.

 

 

Thanks for the insight Sapientiam.

 

Then this might mean the ODAC has been designed to filter out noise, or that my USB port is enchanted by otherworldly magic. I only mentioned "Reduction of noise" because I literally cannot, no matter how many programs I ran, hear any noise of any kind. That is with 6.5x on the O2, where the only thing I can detect (without blowing my ears out), is how badly the O2 distorts the sound at that gain.

 

With this in mind, it may as well mean that getting a USB isolator/ powered hub, will most likely yield no improvements for the ODAC. Whether it is due to circuitry design, or something completely different, I have no idea.

 

I do however have an ELE EL-D01 DAC, but it'll be silly to spend nearly 13x price of the DAC just to see if the sound improves. By the sheer power of elimination, it seems I'd be better off upgrading the DAC and amp .

post #34 of 41

The noise I'm talking about isn't noise that is directly perceived as noise. At least in my experience its not - rather its noise that I only realized I had when I'd reduced it. This noise is rather like a curtain or veil that obscures fine details, shrinks the soundstage (on speakers at least) and saps dynamics. Removing it gives the perceived effect of more drive and momentum in the music and enriches the spectrum of the tonal palette.

 

The effect of a USB isolator can only be found by trying it - its very context dependent whether you'll hear any improvement. If you do it'll potentially be lower siblance on vocals and more tonal richness in instrumental timbres. A cheaper and more reliably rewarding upgrade though (if you have some basic DIY skills like soldering) would be to add some small ceramic capacitors across the ES9023's power supply pins.

post #35 of 41

Thanks for the input, I am definitely up for a bit of DIY!

 

After searching around for a bit (and having no skill in finding the original source), it seems that the ODAC uses "a split digital filter and analog power supplies each with their own filtering and regulation which can be seen by looking at the schematic that is now available on the web."

http://www.head-fi.org/t/611778/brief-odac-impressions/1140#post_8832465

 

If that is the case how would you think a capacitor would help in this regards, and if it would: which sort of capacitance would you recommend to put across the ES9023's power supply pins?

 

Thanks in advance :D

post #36 of 41

That link wasn't the original source - I've followed the design of it from 'Lord Voldemort' (as he's referred to in these parts) for some time. Here's where to go to get a nice picture of the board and a link to the schematic - http://www.yoyodyneconsulting.ca/pages/ODAC.html

 

I'll examine the schematic in more detail now I know you're game and post up my more detailed suggestions for tweaking it in due course. Stay tuned :cool:

post #37 of 41

Having done a bit of due diligence on the ODAC design, I have to say it seems as though Lord Voldemort screwed up. In that the regulator he's using (from Micrel) specifically does not recommend using a ceramic capacitor on its output. But a ceramic capacitor is indeed what he used, in defiance of the manufacturer's recommendations for the MIC5205. There's a thread over on DIYA where one guy in UK tried to modify his ODAC with an extra noise reduction cap on the regulator but ended up with more noise, not less. This is easily explained by the fact that the wrong output capacitor was chosen.

 

Its fixable but with a bit more effort. Given that the regulator on the board is already running into stability problems with its output cap, I'm not going to suggest adding more caps now without some series impedance to help out the struggling regulator. If you're still up for cutting and strapping the regulator's output, let me know. It would involve putting a ferrite bead in series with the track leading from the regulator (U101) to C101.

post #38 of 41
Quote:
Originally Posted by Sapientiam View Post
 

Having done a bit of due diligence on the ODAC design, I have to say it seems as though Lord Voldemort screwed up.


So screwed up that it measures nicely :o . When voldemort folowed ESS specification closely  the results where much worse than what he achieved later .

 

But you can always tweak this thing and see if it does better than stock .


Edited by HaVoC-28 - 2/1/14 at 11:37pm
post #39 of 41

Nice measurements can still be obtained with oscillating regulators, obviously. Which speaks volumes for listening in addition to measurements....:)

post #40 of 41
Quote:
Originally Posted by Sapientiam View Post
 

Having done a bit of due diligence on the ODAC design, I have to say it seems as though Lord Voldemort screwed up. In that the regulator he's using (from Micrel) specifically does not recommend using a ceramic capacitor on its output. But a ceramic capacitor is indeed what he used, in defiance of the manufacturer's recommendations for the MIC5205. There's a thread over on DIYA where one guy in UK tried to modify his ODAC with an extra noise reduction cap on the regulator but ended up with more noise, not less. This is easily explained by the fact that the wrong output capacitor was chosen.

 

Its fixable but with a bit more effort. Given that the regulator on the board is already running into stability problems with its output cap, I'm not going to suggest adding more caps now without some series impedance to help out the struggling regulator. If you're still up for cutting and strapping the regulator's output, let me know. It would involve putting a ferrite bead in series with the track leading from the regulator (U101) to C101.

 

 

This thread and especially your posts  are very interesting. I am not an engineer, or DIY'er, etc so I don't really understand the highly technical stuff.

 

Nevertheless, I've got the following question:

 

Is there anyone on this site or the Internet (DIY-forums, etc.) - who after analyzing the Lord Voldemort's :evil:

design, implementation and the parts he had used - actually improved :tongue_smile: the ODAC?

 

If I were an engineer or a  DIY'er I could not resist the temptation of  improving the ODAC,  just for the heck of it.

post #41 of 41

Certainly after spending some time analyzing the ODAC (and O2) I felt the pull of going one better than both of those. Not the same as improving the ODAC though because the ODAC's design principles I considered to be ill-chosen, based as they were on measurement figures rather than listening. I don't think the ODAC can be improved (apart from correcting design errors) because it fulfills its design philosophy very well - its just that I'd never chose such a design philosophy. Starting from a subjective design philosophy, a completely different design emerges - the prototype for that is shown in my avatar.

 

If there's anyone here interested for me to talk more about that, please ask - I don't want to bore people by blabbering on when no-one's curious...:cool:

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