[cheapskateaudio]

Quote:

 
This is a hobby so just because you don't need overkill to do something doesn't mean that you shouldn't. That's like saying nobody should climb Mt. Everest because Mt. Kilmanjaro is high enough. I built the B22 because it is an interesting design and I thought it would be a challenge, and I enjoy building things. I definitely didn't do it because I needed to. Same reason I am going to attempt building the DIY T2, which makes the B22 look like a cmoy.

 

True. As a hobbyist there's no reason not to build whatever you want regardless of price and time. Just as rightly, a hobbyist's goals could be to find the best price/performance bang for the buck, ie, the helicopter ride to the top of Everest, lol.

 

[Willakan]

I'm not saying all overkill is bad, but when that overkill can be shown to have seemingly no or negative benefit, it is pretty hard to justify.
 
As for whether the O2 could compete with the Beta22, NwAvGuy has put down a $500 (to charity) challenge if anyone can tell his amp from another amp that measures suitably well - regardless of price. Blind conditions mandatory, obviously.
 
 

 

[LizardKing1]

... and no one so far has come out of the subjectivist woodwork to accept the challenge.
 
Following the above metaphor, the step from the Beta22 to the O2 is a huge one which most don't see justified, to it would be like if to get to the top of the Everest costed you 10x more than it costs to get to the top of Kilimanjaro, even though to you the trip is pretty much the same. Most wouldn't even bother to spend more for something they can hardly tell apart. Now, if you really want the top of the Everest for bragging rights and you're ok with affording it, that's great, but most people will be happy with Kilimanjaro and will keep wondering why would you pay that much for something to similar to what they have.
 
That sounded way better in my head.

 

[samsquanch]

Quote:

Also, I found the source of the DC offset "problem" after measuring the same thing myself. We both made the incredibly stupid mistake of testing without any headphones plugged in - with a set of cheap earbuds my DC offset drops to zero incredibly quickly as the residual charge of the caps depletes. I'm assuming you made the same mistake, otherwise better get debugging.

Redid my tests with headphones in, my dc offset is still hanging out at 3mV, but my turn off spike has dropped a considerable amount, from 130mV to 6mV.  I guess those headphones eat up some that voltage, WHO KNEW?!?!?!?!?
 
Ok, so that's way more reassuring.
 
Tomorrow I'll hook it up the the minilyzer/minirator and do some of those tests, THD and such....

 

[bcg27]

3 mV of dc offset is fine.

 

[samsquanch]

Quote:

3 mV of dc offset is fine.

severely true.

 

[DRUB]

Quote:

I'm not saying all overkill is bad, but when that overkill can be shown to have seemingly no or negative benefit, it is pretty hard to justify.
 
As for whether the O2 could compete with the Beta22, NwAvGuy has put down a $500 (to charity) challenge if anyone can tell his amp from another amp that measures suitably well - regardless of price. Blind conditions mandatory, obviously.
 
 

Fascinating! I ordered my O2 from Oliver @ Epiphany Acoustics so I'm looking forward to seeing how it does with my LCD-2's. I've already been flamed in the high-end audio thread on the LCD-2 for suggesting that if a solid state amp measures well it shouldn't affect sound signature (it should be 'transparent', as it were)... interesting times.
 

 

[Head Injury]

Quote:

Fascinating! I ordered my O2 from Oliver @ Epiphany Acoustics so I'm looking forward to seeing how it does with my LCD-2's. I've already been flamed in the high-end audio thread on the LCD-2 for suggesting that if a solid state amp measures well it shouldn't affect sound signature (it should be 'transparent', as it were)... interesting times.

A fellow sound card user 

 
Let me know if there are big differences in sound, particularly if you can blind test it.

 

[DRUB]

Quote:

A fellow sound card user 

 
Let me know if there are big differences in sound, particularly if you can blind test it.

 
Just realised there's an impedance mismatch with the LCD-2 and Asus actually; was reading an article (by NwAvGuy) that looked at the relation between a source's output impedance and the impedance of a headphone and its impact on the frequency response - apparently optimum response is achieved via the output impedance being 1/8th of the headphone impedance. The Asus Essence ST/X has an output impedance of 10.7 ohms, so it actually provides insufficient electrical damping for the Audeze LCD-2 (which has impedance of 60 ohms) - apparently the Asus will roll-off bass frequencies by about 3db, which is definitely audible. I mentioned on another thread that I was initially confused by the LCD-2 I was listening to on my soundcard, as I didn't hear the legendary bass extension. The impedance mismatch explains it elegantly!
 
 

 

[Satellite_6]

Quote:

 
Just realised there's an impedance mismatch with the LCD-2 and Asus actually; was reading an article that looked at the relation between a source's output impedance and the impedance of a headphone and its impact on the frequency response - apparently optimum response is achieved via the output impedance being 1/8th of the headphone impedance. The Asus Essence ST/X has an output impedance of 10.7 ohms, so it actually provides insufficient electrical damping for the Audeze LCD-2 (which has impedance of 60 ohms) - apparently the Asus will roll-off bass frequencies by about 3db, which is definitely audible. I mentioned on another thread that I was initially confused by the LCD-2 I was listening to on my soundcard, as I didn't hear the legendary bass extension. The impedance mismatch explains it elegantly!
 
 

That's kind of a fail. . . 
 

 

[Hennyo]

Quote:

 
Just realised there's an impedance mismatch with the LCD-2 and Asus actually; was reading an article that looked at the relation between a source's output impedance and the impedance of a headphone and its impact on the frequency response - apparently optimum response is achieved via the output impedance being 1/8th of the headphone impedance. The Asus Essence ST/X has an output impedance of 10.7 ohms, so it actually provides insufficient electrical damping for the Audeze LCD-2 (which has impedance of 60 ohms) - apparently the Asus will roll-off bass frequencies by about 3db, which is definitely audible. I mentioned on another thread that I was initially confused by the LCD-2 I was listening to on my soundcard, as I didn't hear the legendary bass extension. The impedance mismatch explains it elegantly!
 
 

I still own an STX (to feed my speakers with it). ; ) I also read Nwavguys article on resistance and electrical damping..
 
That said, I think stx is a great product for anything amped (such as my speakers) but have found (and consistently find) that a 3$ amp circuit is just not enough for headphones... It was the next step up from an Ipod amp, but that's about it.. Unless you're cheap and just want to keep an hd 595... which is a 50 ohm dynamic headphone power handling of like <140mw anyway.. (=*()
 
Orthos take a lot more power than dynamics.. And even truer to that is Stax. 580+Volts! Crazy transients? That's what I'm talking about.
 
 
 
When I was new to the hobby, I actually brought my computer to the store to test the Stx amp section against the HDP. Lol! It's more thin and sterile. It didn't sound live, but more like a reproduction, not that HDP is any perfect piece of equipment at this either, but truly comparison served its purpose, and I bought the HDP.. (This is with the highly venerable 49720's) Basically the differences between the stx / other amps is great... I think you need to hear some other amps when you get the chance HeadInjury.. Although I'm sure your setup still sounds good. =)
 
p.s. I think you should put together an O2 and feed it with your STX.. That's a pretty dang cost effective setup..
 

 

[Paul Blythe]

Looking forward to building a new PC before Christmas so I can use my Asus Xonar STX card with the O2...

 

[DRUB]

Quote:

I also run the STX. (for some reason still own it) ; ) I also read Nwavguys article on matching impedance.
 
That said, I think stx is a great product for anything amped (such as my speakers) but have found (and consistently find) that a 3$ amp circuit is just not enough for headphones... just not enough for headphones... It was the next step up from an Ipod amp, but that's about it.. Unless you're cheap and just want to keep an hd 595... which is a 50 ohm dynamic headphone power handling of like <140mw anyway.. (=*()
 
Orthos take a lot more power than dynamics.. And even truer to that is Stax. 580+Volts! Crazy transients? That's what I'm talking about.
 
 
 
When I was new to the hobby, I actually brought my computer to the store to test the Stx amp section against the HDP. Lol! It's more thin and sterile. It didn't sound live, but more like a reproduction, not that HDP is any perfect piece of equipment at this either, but truly comparison served its purpose, and I bought the HDP.. (This is with the highly venerable 49720's) Basically the differences between the stx / other amps is great... I think you need to hear some other amps when you get the chance HeadInjury.. Although I'm sure your setup still sounds good. =)
 

I used to run studio monitors out of the STX, which sounded fantastic - I really like the card in terms of its line-outs, and I used to have the HD600 which sounded beautiful out of the STX (no output impedance/impedance mismatch as the HD600s are 300 ohms).
 
When I get shipped the Objective2 in about 3 weeks I'll grab a friend and blind test out of the STX and O2 to see if I can note any major differences. 
 

 

[Questhate]

So, count me in the group that has successfully built an Objective2. 
 
Seeing that I have zero DIY experience (this is my first project), and almost-zero soldering experience (other than soldering Grado cables), I was skeptical that I'd see any success. But, the board was very straight-forward and easy-to-follow. Once you lay out all the parts, it was really a piece of cake. For anyone considering this as a DIY project and doesn't have much experience, I can assure you firsthand that it's great for beginners. 
 
I had a bit of paranoia with some of the measurements that I was getting that led me to believe the power management circuit may have been screwed up, but NwAvGuy said it was normal. 
 
Now, all I'm waiting on is the front panels from the group-buy, and we can close this bad boy out. 
 
Haven't had much head-time yet, other than briefly plugging in a pair of T50RP to test it out, but I'll likely post impressions in the other thread. 
 
Good luck to anyone building one. 

 

[cheapskateaudio]

Quote:

So, count me in the group that has successfully built an Objective2. 
 
Seeing that I have zero DIY experience (this is my first project), and almost-zero soldering experience (other than soldering Grado cables), I was skeptical that I'd see any success. But, the board was very straight-forward and easy-to-follow. Once you lay out all the parts, it was really a piece of cake. For anyone considering this as a DIY project and doesn't have much experience, I can assure you firsthand that it's great for beginners. 
 
I had a bit of paranoia with some of the measurements that I was getting that led me to believe the power management circuit may have been screwed up, but NwAvGuy said it was normal. 
 
Now, all I'm waiting on is the front panels from the group-buy, and we can close this bad boy out. 
 
Haven't had much head-time yet, other than briefly plugging in a pair of T50RP to test it out, but I'll likely post impressions in the other thread. 
 
Good luck to anyone building one. 

Cool! This amp is *very* transparent to the source, make sure you know what you've got it plugged into is not junk.