[kramer5150]

Curious....
Anyone on HF prefer to use discrete OP amps?  There was a thread yesterday asking if amp technology has really changed that much over the last decade, and AFIAK discrete OP amps (as comercial products) are one of the newer developments.
 
I have some older amps, (PPA, cmoy) from 6-7 years ago, and am wondering if this might be an upgrade direction worth pursuing?
 
My concerns mainly are... low gain stability (3~5), noise/hum, turn on-off transients, minimal DC offset/output, and of course overall sound quality.
 
Examples:
 
http://www.newclassd.com/index.php?page=55

 
 
http://www.johnhardyco.com/products.html
http://www.johnhardyco.com/pdf/990-2007.pdf
 
http://www.sg-acoustics.ch/analogue_audio/discrete_opamps/index.html
 
http://www.fivefishstudios.com/diy-kits/doa-17-discrete-opamp

 

[kramer5150]

bump?

 

[Chodi]

This is really just another way to modify frequency response and distortion without using eq. Problem with this is that the results are fixed and unpredictable. At least with digital eq you can easily change the frequency response and tweek until you get what you want. Once you buy discrete opa what you get is one flavor with each purchase. Depending on the rest of the circuit this may not be any improvement at all. I played with some of the Audio gd discrete opa's in an Audio gd amp and it, of course, changed things. Was it "better" it was all up to personal listening preference. EQ is way easier and cheaper.

 

[kramer5150]

Did they increase / decrease clarity, instrument separation or alter the soundstage at all?
 
Against what OP amps did you compare?
 
thanks!!  anyone else?

 

[Chodi]

Quote:

Did they increase / decrease clarity, instrument separation or alter the soundstage at all?
 
Against what OP amps did you compare?
 
thanks!!  anyone else?

The question you are asking has to do with the way they present the high frequency. The perception of clarity and instrument separation is simply the way the treble allows your brain to focus on location. Changing opa's can change the treble and therefore change the perception you question. How a specific opa may react in your system is unpredictable. EQ is a whole lot easier.

 

[kramer5150]

Quote:

The question you are asking has to do with the way they present the high frequency. The perception of clarity and instrument separation is simply the way the treble allows your brain to focus on location. Changing opa's can change the treble and therefore change the perception you question. How a specific opa may react in your system is unpredictable. EQ is a whole lot easier.

So sound clarity, separation of sounds and in this case the clarity and separation of layered instrumentation is more a product of each OP amps equalization curve and spectral frequency boosts and cuts?
 
How about sound stage and stereo image?  Do discrete OP amps have an advantage here in their ability to resolve ambiance and the sense of space in recordings?
 
thanks

 

[Mad Max]

Clarity will be fine on any chip unless it is malfunctioning terribly, lol.
 
Soundstaging, layering, separation, stereo image, etc. will not change much as long as you roll opamps that are stable in that specific circuit.  Unstable ones will oscillate to death, you will be able to notice by how the opamp overheats like it wants to melt itself or you will get a "swooshing" sound (sine sweeps), and with it comes reduced sound quality.
 
I suggest upgrading your amp(s) and DAC(s) instead with that money.

 

[kramer5150]

Al right then,  not getting much positive feedback on any of these.  close this chapter.

 

[Hutnicks]

Quote:

Curious....
Anyone on HF prefer to use discrete OP amps?  There was a thread yesterday asking if amp technology has really changed that much over the last decade, and AFIAK discrete OP amps (as comercial products) are one of the newer developments.
 
I have some older amps, (PPA, cmoy) from 6-7 years ago, and am wondering if this might be an upgrade direction worth pursuing?
 
My concerns mainly are... low gain stability (3~5), noise/hum, turn on-off transients, minimal DC offset/output, and of course overall sound quality.
 
Examples:
 
http://www.newclassd.com/index.php?page=55

 
 
http://www.johnhardyco.com/products.html
http://www.johnhardyco.com/pdf/990-2007.pdf
 
http://www.sg-acoustics.ch/analogue_audio/discrete_opamps/index.html
 
http://www.fivefishstudios.com/diy-kits/doa-17-discrete-opamp

I am rather perplexed by this. Before the IC came around discrete was the only amp design avialable. As such there were myriad commercial products. This is nothing new, nothing at all.
 
Biasing and heat dissipation were issues back then and probably still are depending on the transistor choice. Some react to minute temp changes making for a very unstable amp.
That said for the 23 bucks for the above kit, what have you to lose.

 

[duncan1]

The circuit shown on the John hardy link is of good quality. The use of LM 394 at the input is high quality . I have made several amps[loudspeaker]  using that "chip"
                       I also used it in the Stax -717 and it worked well. The circuit is a miniature PA design basically.
                          Having said that JLH  after testing LOW level signals between an audio IC and discrete found there was little difference in the  perceived  sound quality
                                  You also have to admit that the john hardy design uses - a CHIP which although showing 2 BJT in the design is actually made up of multiple BJTs
                                       This used to be made in original discrete version showing many paralleled up to reduce noise etc
.                                         There are other equivalent  chips to the LM394 . The website said it compared it to a 5534 I don't care what D.Self says
                                             The modern -up to date HIGH quality audio chips are much better sonically  than that chip.