[balou]

Today, I had finally some time to put my denon cdp together, and it's headphone out just blows my cmoy away.
The output from every chan goes from the DAC to a NE5532 (yup, two opamps in one chan) for the brickwall filter and such, and then to one half of a JRC4556, latter being the same chip as in the Grado RA1.

My cmoy just replaces the cmoy-like headphone stage with well, the cmoy design, with an AD8066 in it.

While it now has at least some soundstage (no such thing with the opa2132), the cmoy is still easily beaten by the internal headphone amp. The cmoy sounds thin and harsh, whereas the jrc4556 seems to deliver the music with ease and much more fullness.

This is quite interesting... jrc4556 got double the output current, and the sound improvement is quite remarkable, despite being such a low cost chip. Is this improvement really due to the doubled output current?

And while I'm at it, are there any other similar high current output chips, apart from the AD8397?

 

[dsavitsk]

Try the LM6172

 

[slwiser]

Check out the amplifier technology called SATRI which is a current amp instead of a voltage amp. There is quite a bit of interesting reading about the current amp in Japanese.

 

[balou]

current amp... seems like another word for buffer to me. have you got a link in english about satri?

 

[slwiser]

Quote:

Originally Posted by balou /img/forum/go_quote.gif current amp... seems like another word for buffer to me. have you got a link in english about satri?

There really is very little concerning this in English. But I have used Google to good use.

You may very well be right in it being some type of buffer. What is important to me is the headphones impedance relationship with an amps current capacity. I think an amp with the right synergy with a headphone's impedance can either sound weak or strong at those frequencies. Another way to say it is that if a headphone has a peak in its impedance curve you will tend to hear a stronger response in that area where if you used a headphone with a flat impedance curve the amp would sound weak in comparison when it really isn't weak. My gallery has several headphone charts for impedance curves just for this type of discussion.

The real point with the SATRI is that no matter what the headphone impedance curve the amp will provide a balanced signal whereas the voltage amp will not be able to do this thereby giving the impression of having better synergy with some amps while the SATRI amp provides a level field based on current.

 

[NelsonVandal]

Cool, this SATRI thing. It seems to be an amplifier that doesn't amplify. It uses transistors, but the audio signal doesn't pass through them!? It gains the signal 20 dB in some way. The ambition was to build an amplifier that doesn't color the sound (just the way I want it). If the input is zero - there's zero noise! The distortion is also zero! Wow, this is exactly the amp I want... if it's true. The SATRI seems to be an IC, and I'm not even sure if there is something digital going on in it.

Sijosae has made something he calls a SATRI amp:
http://translate.google.com/translat...&hl=en&ie=UTF8
I wonder if this is a real SATRI amp. The signal passes JFET's and bipolars in this one and finally a diamond buffer. Is this just an all discrete amp? Has anyone built this?