Thanks for the encouragement, Tao!

Some more food:

John Chapman: Quote:

It may be good for individuals with specific gear. My main problem is it seems to require specific headphones and a specific source to work optimally. It limits your choices of sources to those with low ouput impedence. Rather than picking your source over, say, its DAC you are forced into picking it based on its output impedence.




JAZZ, I still kinda like the idea, but I am trying to find a better alternative to active amps for all audiophiles, not just those with low output impedence sources.



I would be more than happy to reconsider passive amps (just as I reconsidered active amps) if there was a way to bypass the impedence problems. I thought a transformer might do that....but I take it from the dicussion that it can't

Czilla...
Quote:

I would be more than happy to reconsider passive amps (just as I reconsidered active amps) if there was a way to bypass the impedence problems. I thought a transformer might do that....but I take it from the dicussion that it can't

...yes, of course it can! Read John Chapman's last comment! He just suspects that the mentioned type of transformer wouldn't work adequately. See also this transformer-based «passive amp» from ASL!

dd3mon...
Quote:

Good work, I'm glad someone finally took an intelligent approach to investigating this issue. Now we know.

The question is: now we know what. 1. that the source should have a low output impedance (I/we already knew this before); 2. that transformer-based attenuators should be tailored to the individual components, at least to headphone operation. I even don't think that my own approach (by testing and listening, including some theoretical considerations) was dumb, BTW. It's not amiss to try your ideas and considerations in practice.

Quote:



I guess the transformer wouldn't make any sense in a circuit where the attenuation is buffered anyway. A common potentiometer does he job very well. But if the concept you have in mind really consists of just one amplification stage, you probably would be disappointed from the unspectacular, unvarnished sound. It's most likely very similar to the direct-path sound in my approach. It may be the same experience like with renouncing the pre-amp in a speaker rig. Amps do add warmth, coherency and color to the sound. (I'm generalizing this because there has been no exception in my audio career, neither with pre-amps nor with headphone amps.) Nevertheless, the downside - their deficits with dynamic, transient speed and resolution - is most likely rather perceived as euphonic than as a disadvantage.

Quote:




Hi Czilla. Welcome to about 2 months ago.

Guys, let's lay off the "I told you so" comments. It took a lot of class for Czilla9000 to post this exchange.

People, you're incredible! You just believe what you want to, pick out the arguments you like and build up proofs out of misunderstandings. But it seems like a curious kind of democracy: if the majority has decided that something is «proved», arguments have no chance anymore. If they ever had at all. Note: Nobody has proved that the direct path doesn't work. It works very well, but just doesn't meet the expectations and idealizations, and that's its sentence of death.

Czilla's change of mind is based on a misunderstanding. But this doesn't matter, because the signal is given, and that's what counts: another direct-path advocate is giving in. In fact John Chapman is also a direct-connection advocate and supports the idea of driving headphones directly. All he was saying is that the concerning TX102 transformer which is designed for higher impedances most likely won't work for headphone direct drive. But he thinks that special designs will work well, as BTW proved by ASL with its Reference Tools.

So if you want to hear my opinion: It's a lousy work you have done within this thread.

Quote:



Anyone know what's on the inside of the Kenwood RD-VH7? Because I think this is exactly what this is.

So does the "Reference Tools" not suffer from any impedence problems?

Not to wake the dead but the problem with impedance is one of volume, period. Basically you start with xV and then split it based on the ratio of output/transformer/headphone impedance.

The key would be getting enough V to the headphone to produce good levels. Good being different for just about everyone. So you are more likely to have success with a high impedance phone like a Senn, AKG or Beyer than a Sony, A-T or Grado. The problem becomes making a list of known cd players or dacs with low output impedance. Or better still ones with both a low output impedance and a volume control. The Monarchy Audio DACs come to mind for volume, not sure about impedance.

Quote:



It's designed not to. I will soon get one to try it. According to John it will most likely do the job perfectly. He also thinks that the transformer approach is slightly more forgiving, whereas resistor-based attenuators possibly are more accurate (that's the result of our AudioCircle communication for the time being); but they're also more critical in view of the output impedance.

BTW your Radioshack attenuator also doesn't «suffer» from any impedance problems. Obviously it sounds good to your ears, and if it alters the source sound it's in a minor degree or even in a synergetic manner. Certainly it alters the sound less than any amp (which in turn are allowed to cause synergetic colorations...). Don't let others indoctrinate you with what's good and what's bad!

JaZZ,

...so what does ASL "reference tool" use inside to attenuate?(ok, nevermind its transformer based) and how does the design/parts used addresses the impedence issue?

interesting thread you got going there at audiocircle

Tao...

Quote:

...how does the design/parts used addresses the impedance issue?

Provided that the output impedance is 200 ohm or less, there should be no problem; the transformer creates low output impedances for the headphone and high load impedances for the line-out amp (though unconstant values for different volume settings).