[cn11]

O2 sonically does edge out my AMB M^3 (w/power supply). No doubt about it. While I'd say the AMB can hardly be considered top of the line, that's still a pretty hefty performance/value ratio represented by the O2. 

 

[keanex]

Quote:

And the fact that every connector is at the front of the amp ? Mr Slim must have made a few changes to move things like power to the rear - a much nicer design choice.

 
Apparently this is an easy fix for those building their own, so not a problem at all for anyone building one.

 

[mikeaj]

Quote:

Quote:

And the fact that every connector is at the front of the amp ? Mr Slim must have made a few changes to move things like power to the rear - a much nicer design choice.

 
Apparently this is an easy fix for those building their own, so not a problem at all for anyone building one.

 
You do it by facing the PCB backwards so all the ports are facing the back.  Then use panel-mounted jacks on the front side (to have these fit, you need a larger enclosure than standard).  It's a little more involved, but of course, jacks placement is never a huge deal for a DIY build.

 

[Draygonn]

You do it by facing the PCB backwards so all the ports are facing the back.  

 

[PeachesNCream]

Quote:

 
Apparently this is an easy fix for those building their own, so not a problem at all for anyone building one.

 
EDIT: V has stated that a desktop version is in development.
 
Answered my own q.
 
Cheers,

 

[Anaxilus]

Quote:

Some of us are pestering Voldermort to make a 'stat amp after he's done with his current projects...
 
O2HV?  O2ES?
 
Let's dream!   

Gee, sounds like a good idea!  

 
I'd be interested in hearing his analysis of the T2.  That's the best (transparent, resolving, dynamic) stat amp I've heard yet.  Just ask him to keep the wine, watches and cars out of it.  Women are okay (w/ pics).
 
Toss him these:
 
http://gilmore.chem.northwestern.edu/t2schem.pdf
 
http://gilmore.chem.northwestern.edu/t2schempower.pdf
 
 

 

[maverickronin]

Quote:

Gee, sounds like a good idea!  

 
I'd be interested in hearing his analysis of the T2.  That's the best (transparent, resolving, dynamic) stat amp I've heard yet.  Just ask him to keep the wine, watches and cars out of it.  Women are okay (w/ pics).
 
Toss him these:
 
http://gilmore.chem.northwestern.edu/t2schem.pdf
 
http://gilmore.chem.northwestern.edu/t2schempower.pdf

I'll probably talk to him about the idea sometime in the future when he's not so busy with other projects.  You can always just leave a comment on his site if you want.

 

[painter]

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Quote:

Originally Posted by painter /img/forum/go_quote.gif
 
Do people know that a design like the O2 creates several magnitudes more distortion than a Single Ended Triode amp ?    How can that be and it measure so well?   Well the O2 design cancels its internal distortion with very heavy Negative Feedback.  I built an O2 and yes it does a great job of cancelling its high distortion with NFB without resorting to such a high bandwidth that it is susceptible to oscillation,  it is a unique design, very very black background  and perfect if you think the job is done at the headphone jack.

 
Why do you think the O2 creates several orders of magnitude more distortion ? This might have been true of obsolete, very low-end, incorrectly used, or non-audio op-amps, but decent modern ones have reasonably low distortion even without negative feedback. Check here for some examples; note that this PDF shows the performance of op-amps with significantly reduced negative feedback (by a ratio of ~1000, basically open loop at very high frequency). Additionally, why would anyone care about some theoretical distortion that would occur without feedback, when the only thing that matters is what actually appears on the output ?
 

The reason to care about distortion of bjts without NFB is simple but hard to grasp for those not trained in controls.  The problem is this hobby is multi-disciplinary.  Not soley electrical engineering, rather a mix of many fields of engineeering and science
 
For the EE like NvAvguy,  the loop is from the output of the amp/load back to the gain device with the NFB cancelling distortion.  You seem to be one of the few who gets this concept. Thats good.
 
The other philosophy is the control "loop" is from our hearing perception back to the amplification device.  The concept is that a for example a 45 SET amplification device generates a distortion pattern that is easily "cancelled" by human perception because of the mechanics of air, our temporal membrane, evolution,  and **** no one understands.  Its a natural feedback loop.
 
I am not saying which concept is right.  Only that I keep an open mind about this stuff.
 
But I know for a fact that my O2 does not sound as good as my little we417 SET up to about 10 mW,  and I trust my perception more than a dScope.   I think people who spend $5k+ on old Moth 2A3 SET's are not fools,  but rather trust their hearing more than a limited electrical engineering model.
 
That's not a knock on the O2,  it is a marvelous design,   very versatile stable and inexpensive to build.  Fits the needs of 90% of folks and their headphones.  
 
 

 

[maverickronin]

Even if what I think you're trying to say is right...
 
psychoacoustics  =/= feedback
 
Also, saying that Voldermort isn't being interdisciplinary is pretty silly too.  His last article was about psychology and even touched on cognitive neuroscience for $DEITY's sake!  Where do you think he got the standards he designed to from?

 

[cce121]

Quote:

Quote:

Isn't that the whole entire point of Head-Fi?
 
... oh wait.

 
I think this explains it all. And why are we even here as well. 

 

[stv014]

Quote:

Originally Posted by painter /img/forum/go_quote.gif
 
The other philosophy is the control "loop" is from our hearing perception back to the amplification device.  The concept is that a for example a 45 SET amplification device generates a distortion pattern that is easily "cancelled" by human perception because of the mechanics of air, our temporal membrane, evolution,  and **** no one understands.  Its a natural feedback loop.

Not sure how any of the above is relevant to the difference (or lack of it) between an amplifier with negative feedback, and another with no feedback that produces the same output with low distortion. Also, it is not clear what kind of "loop" is there from perception back to any device, or what a "temporal membrane" is.
The triode amplifier with high measured distortion may sound better because it - due to some lucky coincidence - partly cancels out the distortion of the headphone or loudspeakers, or the distorted audio sounds better subjectively, at least on some source material, even though it is less accurate (similarly to how a bass boost or other effect is perceived as an improvement), or the better sound is simply imagined.
 

 

[akiroz]

While its all good that people are sharing their listening experience, has anyone here actually done any listening tests between the O2 and some of the "big boys" out there?
And by "listening tests" I mean proper blind testing with proper test conditions, the same way you'll do a lab experiment (if any of you do science).
If so, do you mind sharing the results?
 
I've done some blind testing with a discrete amp that I designed and built myself which I thought sounded better until doing some actual tests with 30 trials per person done with 3 people, 90 data points total. Results shows that the O2 amp was better, but of corse  my discrete amp was cheaper than the O2 and hardly a benchmark.
 
btw, can someone please tell me what "TOTL" stands for?

 

[PeachesNCream]

Quote:

While its all good that people are sharing their listening experience, has anyone here actually done any listening tests between the O2 and some of the "big boys" out there?
And by "listening tests" I mean proper blind testing with proper test conditions, the same way you'll do a lab experiment (if any of you do science).
If so, do you mind sharing the results?
 
I've done some blind testing with a discrete amp that I designed and built myself which I thought sounded better until doing some actual tests with 30 trials per person done with 3 people, 90 data points total. Results shows that the O2 amp was better, but of corse  my discrete amp was cheaper than the O2 and hardly a benchmark.
 
btw, can someone please tell me what "TOTL" stands for?

Top Of The Line
 
Cheers,

 

[proton007]

 
Quote:

While its all good that people are sharing their listening experience, has anyone here actually done any listening tests between the O2 and some of the "big boys" out there?
And by "listening tests" I mean proper blind testing with proper test conditions, the same way you'll do a lab experiment (if any of you do science).
If so, do you mind sharing the results?

Yeah, that'll be good to know.

 

[chrislangley4253]

I would like to see the same, even if it gets the thread moved to sound science.