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O2 vs TOTL - Page 38

post #556 of 582
Quote:

Originally Posted by jaddie View Post
<snip>

 

What we don't know is what the total end result is of driving the Stax with a transformer "amp" driven by a relatively low power headphone amp.  There are other things going on relating to the headphone/transfomer/amp interface.

 

I can't quickly locate any info on the Stax transformer, but there could be some issues with the impedance it reflects back to the amp.  I was also under the impression that those things were meant to be driven from a speaker amp output, though that's a pretty distant and fallible memory.    

 

It would be interesting to know the gain setting you used on your O2.  Did you drive your Stax transformer from high gain or low gain?

post #557 of 582

Just to play devils advocate a bit biggrin.gif I'm going to point out how completely I disagree with the following point:

Quote:
Originally Posted by jaddie View Post
I'm not on board with the concept that distortion can result in better sound.  Increasing distortion, and IMD is never in and of itself perceived as an improvement. 

 

Distortion is desirable and sought after all the time!

 

 

Granted, this is not about HiFi reproduction at all, but rather the amp and cabinets are considered part of the instrument itself and the distortion is part of the instrument's tone.

 

Just a little different perspective L3000.gif

 

Cheers!

post #558 of 582

I am not on board with that idea either. There's a difference between sound reproduction and distorting electric guitars.

post #559 of 582
Quote:
Originally Posted by xnor View Post

There's a difference between sound reproduction and distorting electric guitars.

Exactly! That is why I wrote this:

Quote:
Originally Posted by ab initio View Post

 

this is not about HiFi reproduction at all,

 

I just thought it was worthwhile to point out that pro audio applications consider the amplifier and speakers to be part of the "tone" and it is a part of the artistic process to choose amps and speakers with the desired sonic colorations.

 

I agree 100% that for Hi-Fildelity reproduction, the goal is 0% distortion with completely balanced frequency response and linear phase response.

 

The point of my post was to help people understand why and where the distortions introduced by tube amplifiers are desirable; namely, in artistic generation of sound---not in HiFi, where the name of the game is to minimize distortion!

 

In my experience, because of the proliferation of electric guitar in popular music, the public perception of "amplifiers" is that "the tube ones sound the best---look at Jimi Hendrix, Led Zeppelin, Eddie Van Halen, Metallica, (insert any guitar-centric band), etc..."  I think this helps perpetuate the perception in the HiFi world.

 

Tubes came before transistors; hence, the first HiFi amplifers necessarily were of tube design. Then, solid state transistors were introduced and amplifier design needed to be re-learned to deal with the new and different design issues. The first solid-state designs didn't have the years of experience behind them, and so for a while, the tube systems had an advantage. We are at a point where solid state design is mature, and clearly, the top performers in terms of measureables are solid state. However, because of the reasons I previously listed, the perception of the merits of tube design for HiFi audio is being perpetuated.

 

Hopefully this help clarifies the point i was making, and my stance on the topic.

 

 

Cheers

 

EDIT: Let me clarify before I get completely crucified: Both tube and solid state designs are capable of excellent HiFi performance---same goes for pro audio as well---but they require different approaches, and I dare say it is easier/simpler to get HiFi from solid state, while it is easier/simpler to get a pleasing colored sound (Pro audio application) from tubes.

 

Okay...

Ready, set, flame me tongue.gif


Edited by ab initio - 7/23/13 at 12:02pm
post #560 of 582

I can't quickly locate any info on the Stax transformer, but there could be some issues with the impedance it reflects back to the amp.  I was also under the impression that those things were meant to be driven from a speaker amp output, though that's a pretty distant and fallible memory.   

 

It's a Stax SRD-X Professional. It has RCA inputs on the back and can be run from 8 C batteries as well (though bass takes a noticeable hit in quality when this is done).

 

One of my theories in why my Little Dot 1+ sounds much better in this application is that it has more current on tap than the O2. It's an amp tuned deliberately to power low-impedance, high-current headphones like Grados. This theory also conveniently explains not only why my Stax amp sounds worse on battery, but also how my Stax amp will draw forty amps of current in about a day of runtime. Then again, this is based on only a passing knowledge of electrical engineering and I have no way to verify or test this.

 

Also, from what I have read and experienced, the reason that tubes are perceived as better in terms of guitar amplifiers and the like is because the low-order distortion reduces the harshness of the sound, while the high-order distortion of transistors makes it worse. Not to mention the fact that tubes overdrive and clip far more pleasantly than a transistor amplifier (though this effect can be simulated to a degree with transistors). While high-end transistor amplifiers will beat high-end tube amplifiers in this mindset because they don't have to deal with the distortion issues that lower end amps do, low end tube amps will sound better than equivalently priced low-end transistor amps because of the inherent benefits of the tube technology.


Edited by Tus-Chan - 7/23/13 at 12:12pm
post #561 of 582

@ab initio: I know and I am thankful that you further clarified your post.

 

 

@Tus-Chan: Grados are not high-current headphones. Unless I'm missing something here, why would you need high current to drive the input of another amp? Shouldn't the amp's input be several kOhms high? With proper gain the O2 is able to output 7V based on real measurements while the LD1+ can output 150 mW into 300 ohms which is ~6.7 V based on specs.

 

Low end tube amps beat equivalently priced low-end transistor amps? Really? In my book they lose in pretty much any measurable (and subjectively audible) way. Just take a look at what a hand full of transistors cost and compare that to tubes.

post #562 of 582

Grados are not high-current headphones. 

 

Then why do I constantly see this exact amplifier used and recommended by people (with more than enough money to get a higher-end amp) for this exact reason? Can you prove your statement?


Unless I'm missing something here, why would you need high current to drive the input of another amp?

 

Because the transformer that converts the signal to high voltage is weak.


With proper gain the O2 is able to output 7V based on real measurements while the LD1+ can output 150 mW into 300 ohms which is ~6.7 V based on specs.

 

"Proper gain" you will virtually never see in the wild because NwAvGuy makes unwarranted assumptions about how his products will be used by the people who own them


Low end tube amps beat equivalently priced low-end transistor amps? Really? In my book they lose in pretty much any measurable (and subjectively audible) way. Just take a look at what a hand full of transistors cost and compare that to tubes.

 

Maybe for the cheapest of the cheap amps, where a tube amp would have to take serious shortcuts in order to match a lowest-end transistor amp's price.

post #563 of 582
Quote:
Originally Posted by Tus-Chan View Post

 

Then why do I constantly see this exact amplifier used and recommended by people (with more than enough money to get a higher-end amp) for this exact reason? Can you prove your statement?

Lots of non-in-ear headphones require more current: http://www.head-fi.org/t/668238/headphones-sensitivity-impedance-required-v-i-p-amplifier-gain#post_9529378

Some even have a higher impedance and still require more current. Grados also require little voltage so an amp with high gain really is not a good choice.

 

The following is subjective, but I'm guessing that the extra distortion makes Grados more listenable (also see the point above with bass roll-off and high harmonic distortion at low frequencies). More "listenable" because I really cannot stand treble peaks so I never made it through an extensive listening session with Grados.

 

 

Quote:
Because the transformer that converts the signal to high voltage is weak.

It would be interesting to see some specs of that amp/transformer, but a quick search didn't result in anything useful.

Maybe you have something, like the manual?

 

 

Quote:

"Proper gain" you will virtually never see in the wild because NwAvGuy makes unwarranted assumptions about how his products will be used by the people who own them

The defaults are fine for almost all portable and desktop sources. And btw, with the default gain of 2.5x you're only 2.5 dB away from what the LD1+ can output according to specs, with a 2 Vrms source. You could tune this to 3.5x if and only if your source doesn't output more than 2 Vrms.

 

NwAv didn't make unwarranted assumptions. He chose the defaults to work well with most devices, even non-standard audiophile sources that output 2.5 Vrms or portable players that output a little above 1Vrms. If those audiophile non-standard sources didn't exist he could have chosen a higher low gain.

 

Anyway, changing two resistors is all it takes. Big deal. You can also order it with custom gain...

 

 

Quote:
Maybe for the cheapest of the cheap amps, where a tube amp would have to take serious shortcuts in order to match a lowest-end transistor amp's price.

Name a few if you can. I'm sure we can come up with cheaper solid state amps that perform better.


Edited by xnor - 7/26/13 at 9:03am
post #564 of 582
There is one thing I don't understand about the O2 and the so called I'll show you all the specs thing from the designer's blog. Where are the power output specs? I've been searching for days and couldn't find the o2s power output specs in impedances other than 32 ohms.
post #565 of 582
Quote:
Originally Posted by donunus View Post

There is one thing I don't understand about the O2 and the so called I'll show you all the specs thing from the designer's blog. Where are the power output specs? I've been searching for days and couldn't find the o2s power output specs in impedances other than 32 ohms.

Read the graphs on THD+N vs Max output power, specifies power for 15 - 600 ohms. 

post #566 of 582

Look for this type of graph, THD+N vs. voltage. You can calculate the power from the clipping voltage and the impedance (P = V^2 / R). It is also shown in some tables that compare various amplifiers.

post #567 of 582

By the way, similar graphs are also available at InnerFidelity. These show slightly less power into low impedance loads, which may be the result of the 12 V/200 mA power supply from JDS Labs not being enough, or just random variation between the current limits of the NJM4556 chips.

post #568 of 582

Thanks guys. I'll look into it. Anyway I already have an O2 and feel it is a great amp for the money. I just wanted to see more info about the power and whether they can drive the k501 or k612 adequately for higher volume listening.

post #569 of 582
Quote:
Originally Posted by donunus View Post

Thanks guys. I'll look into it. Anyway I already have an O2 and feel it is a great amp for the money. I just wanted to see more info about the power and whether they can drive the k501 or k612 adequately for higher volume listening.

 

It only takes about 100mw to give most headphones enough volume to hurt your ears. It may or may not require more power to bring the headphone closer to its potential. So with that said the O2 in terms of volume should work with just about any headphone. Pretty sure some people use the O2 with LCD/HE-500(low impedence) and others use it with the HD600, so it works well enough across all impedance values in terms of volume.

post #570 of 582
Quote:
Originally Posted by Llloyd View Post
 

 

It only takes about 100mw to give most headphones enough volume to hurt your ears. It may or may not require more power to bring the headphone closer to its potential. So with that said the O2 in terms of volume should work with just about any headphone. Pretty sure some people use the O2 with LCD/HE-500(low impedence) and others use it with the HD600, so it works well enough across all impedance values in terms of volume.

 

What if I wanted to drive a headphone like HE-6? Would the O2 be up the to task? If not, what's a solid and reasonably priced amp that will?

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