Discrete Opamp Open Design - Page 7

RNMarsh · 07:16 AM

Quote:

Originally Posted by dirkwright

May I ask why 30 ohms? I think opamps are usually spec'd for 600 ohms.

This amplifier will be used for other than driving 600 ohm input Z's. Driving headphone z is a current application for such circuits. About 1/2 of the headphones are below 600 Ohm Z.
30 ohms is not uncommon. For example, two of my headphones (Senn HD800 and HiFiMan HE6) are 300 and 50 Ohms.

Ic are limited in power handling but this is a discrete design and no such limitation need exist. Thx - RNM

PMA · 23rd August 2012, 07:16 AM

You professional guys want for DIY audience to design a "discrete opamp" that you would use in your commercial designs?

homemodder · 23rd August 2012, 10:04 AM

I hope we see a design come of this thread that is new or at least has some novelty, tweak or improvement over circuits most of us have seen shown here to death. That includes circuits that some experts believe is new but are available all over the internet and as old as 30 or more years. Possible ???

Bonsai · 23rd August 2012, 11:04 AM

I don't disagree with this, but as always, the devil is in th detail. Probably 80% of those designs have the wrong trade offs and are subsequently sub optimal.

Yes, i also hope we se something novel and with 8 trannies, it's going to have to be.

:-)

dirkwright · 23rd August 2012, 12:14 PM

Lots of talk, no action. sigh....

homemodder · 23rd August 2012, 12:16 PM

True but one designer may optimize for a different reason which may not be obvious to you but important factor to him, so how can one judge that his way is not optimal afterall it is trade offs. For instance J Curl will optimize for wide bandwith but this is not neccesarily good for THD while Edmond will go out of his way to post lowest possible THD. Which one is suboptimal ??

I think the percentage is much smaller than that, probably less than 10 percent when it comes to commercially available equipment.

homemodder · 23rd August 2012, 12:24 PM

Quote:

Originally Posted by dirkwright

Lots of talk, no action. sigh....

Patience please, geniuses at work on it.

And then comes the dissapointment of seeing something weve seen years ago.....

dirkwright · 23rd August 2012, 12:26 PM

So, some schematics a copied off a simple search. So much talk, so little action.

dirkwright · 23rd August 2012, 12:27 PM

Quote:

Originally Posted by homemodder

Patience please, geniuses at work on it.

And then comes the dissapointment of seeing something weve seen years ago.....

It doesn't have to be unique. It just has to meet specs.

dirkwright · 23rd August 2012, 12:43 PM

A few more for inspiration.

23rd August 2012, 07:16 AM	#62
PMA diyAudio Member Join Date: Apr 2002 Location: Prague, Kitakyushu, Fukuoka	You professional guys want for DIY audience to design a "discrete opamp" that you would use in your commercial designs? __________________ Pavel Macura http://www.linkedin.com/pub/pavel-macura/4/783/637 http://web.telecom.cz/macura/audiopage.html

23rd August 2012, 11:04 AM	#64
Bonsai diyAudio Member Join Date: Aug 2006 Location: Taipei, Taiwan	I don't disagree with this, but as always, the devil is in th detail. Probably 80% of those designs have the wrong trade offs and are subsequently sub optimal. Yes, i also hope we se something novel and with 8 trannies, it's going to have to be. :-) __________________ bonsai Amplifier Design and Construction for MUSIC! http://hifisonix.com/

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23rd August 2012, 10:04 AM	#63
homemodder Account disabled at member's request Join Date: May 2006	I hope we see a design come of this thread that is new or at least has some novelty, tweak or improvement over circuits most of us have seen shown here to death. That includes circuits that some experts believe is new but are available all over the internet and as old as 30 or more years. Possible ???

23rd August 2012, 12:14 PM	#65
dirkwright diyAudio Member Join Date: May 2011 Location: Virginia	Lots of talk, no action. sigh....

23rd August 2012, 12:16 PM	#66
homemodder Account disabled at member's request Join Date: May 2006	True but one designer may optimize for a different reason which may not be obvious to you but important factor to him, so how can one judge that his way is not optimal afterall it is trade offs. For instance J Curl will optimize for wide bandwith but this is not neccesarily good for THD while Edmond will go out of his way to post lowest possible THD. Which one is suboptimal ?? I think the percentage is much smaller than that, probably less than 10 percent when it comes to commercially available equipment.