[estreeter]

Name dropper.   :crybaby:

 

[mikeaj]

Quote:

Mine's been on almost 24/7 for about 3 months now with several hours of use every day and it still works perfectly.
 
Of course mine was built by Voldemort himself so it must be magic...

Hm, maybe I shouldn't power cycle all the time, particularly when testing.  Power cycling is generally more stressful than just leaving something on all the time (unless it gets hot when on), not that I particularly expect undue durability issues either way.
 
 
I'm going to guess that shorting the output (by unplugging or plugging in headphones) with no music playing is less stressful than a power cycle?  NJM4556 with 1 ohms resistor on the output can handle being regularly shorted, or is that a bad idea?  It's just pushing the small ~4 mV DC offset through the internal output impedance through the 1 ohm resistor into ground, and such is harmless, or am I overlooking something (well, 2x op amps per channel)?
 
I'm asking more out of curiosity than anything else.

 

[wakibaki]

It doesn't say anything about short circuit in either of the datasheets I've got so that means it can be damaged by a SC in adverse circumstances, I guess. Normally if an opamp has protection that's extolled in the datasheet since it's a desirable feature.
 
It shouldn't suffer unduly in the circumstances you describe though, although it might be different when driven.
 
w
 
It's not a big deal if it does blow up, just an inconvenience, particularly if you have socketed the chips, they're not expensive. 

 

[fubar3]

Quote:

Most failures in parts occur early in their life, if you buy a commercial product it will most likely fail early within the warranty period
w

Agreed, I hate to bring up "burn in" but it is a good thing for electronic circuits although controversial for other audio components.
 

 

[deadlylover]

Quote:

Agreed, I hate to bring up "burn in" but it is a good thing for electronic circuits although controversial for other audio components.

 
You don't want to anger the wrong kind.
 
Let's call it stress testing.

 

[shadow419]

Quote:

 
You don't want to anger the wrong kind.
 
Let's call it stress testing.

I like that.  Burn bad, stress good!

 

[kingpage]

Quote:

 
You don't want to anger the wrong kind.
 
Let's call it stress testing.

The kind of stress testing that's usually performed involves a dummy and a lot of smashing.

 

[maverickronin]

Quote:

I'm going to guess that shorting the output (by unplugging or plugging in headphones) with no music playing is less stressful than a power cycle?  NJM4556 with 1 ohms resistor on the output can handle being regularly shorted, or is that a bad idea?  It's just pushing the small ~4 mV DC offset through the internal output impedance through the 1 ohm resistor into ground, and such is harmless, or am I overlooking something (well, 2x op amps per channel)?
 
I'm asking more out of curiosity than anything else.

He said somewhere that he tried shorting them for longer periods of time and then comparing the measurements before and after and he didn't find any changes at all.  I'm pretty sure he also said he couldn't find a way to make them fail at the voltages he decided on.
 
I'd probably have to dig through all the articles, comments, and the diyAudio thread to find the exact quotes though.

 

[deadlylover]

Quote:

He said somewhere that he tried shorting them for longer periods of time and then comparing the measurements before and after and he didn't find any changes at all.  I'm pretty sure he also said he couldn't find a way to make them fail at the voltages he decided on.

 
That's nice and all, but will it blend?
 
He was just asking for trouble by designing the amp to be that small. Here's hoping that the desktop version won't suffer from such a critical flaw.

 

[Willakan]

What critical flaw? Have had very little sleep, am I missing something?

 

[gates_2]

If anyone is interested in trying this amp, I threw one of my complete O2's up for sale here on Head-Fi (I built 2)

 

[wakibaki]

Quote:

"burn in"

 
Quote:

stress testing.

 
Quote:

stress testing

Not so much 'burn in' as 'not burn out'. We took the military radios and put them in an oven and ran continuous Bit Error Rate testing on them.
 
 

What critical flaw? Have had very little sleep, am I missing something?

That's an omission, rather than a flaw IMO. What he has done is to fail to provide a guarantee of short circuit protection. Accepting a manufacturers specification. which is all that designers of opamp based headamps can really offer, is not a guarantee of short circuit protection although it is evidence of due diligence if short circuit protection is claimed.
 
Short circuit protection is not claimed. A failure to claim it could be seen as a flaw. but with the background information he's provided as evidence of at least having considered the issue you have to accept the fact that it is not a no-compromise amplifier with a degree of charity. As I said already, if it blows up, it's no great loss, the chips are as cheap as ...chips.
 
w

 

[Willakan]

Dunno, I always took it that you shouldn't short-circuit the output stage of any vaguely high-power amplifier (OK, it's not a power amp but it can still break itself given enough time).
I don't mean that to read condescendingly/sarcastically or anything, I just genuinely thought that was common practise, even amongst audiophiles.

 

[LizardKing1]

Quote:

No measurements yet

, along with the fact that it looks like he's made a deal with someone and could potentially stand to make a profit from sales of the DAC board.  I hope this isn't the case though.
 

Go to the article, scroll halfway down and read a very obviously entitled paragraph "No money for me". He says there has to be a commercial ODAC because it's much harder to assemble than the O2 or the ODA, but that doesn't mean the commercial profit goes to him.

 

[kiteki]

 
The O2 and ODAC are becoming all the rage in China now - http://erji.net/read.php?tid=1140434&page=e
 
 
 
Why does Erji.net have such funny avatars compared to head-fi?