Discrete opamp bjt front end

That datasheet seems to be written for those phools, who believe any technobrabble, Diagrams and important data are missing instead. Some important data like input bias=2.2uA is listed, but not mentioned in the text, making it unsuitable for a lot of applications. Offset voltage and -stability can only be guessed. The noise is mentioned for the input device only and the capacitor drivel can be read better in the AVX datasheets. Beware of shorts, there seems no output protection! That thing is IMHO useful only for driving transformers, inductive backcurrent can be absorbed. The inductors are probably in there for your point 2), they might give some extra phase margin, but will increase distortion. I do not like those speed-up diodes across the inputs either. But I do like the gold plated pins!

What a piece-a-crap.

I've got to get into this audiophool business... looks like all kinds of dummies sitting there ready for the taking ;-)

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

On a sunny day (Wed, 29 Nov 2006 10:14:10 -0700) it happened Jim Thompson wrote in :

Well, I dunno, count me in as one if them if you must, nice sales talk in that pdf, but the thing does what it does. What is wrong except specifying resistors in Watts, not Ohms? :-)

Well, as one who designs another OpAmp into a chip every few months, that "design" is junk.

...Jim Thompson

On a sunny day (Wed, 29 Nov 2006 11:15:07 -0700) it happened Jim Thompson wrote in :

OK, so you are responsible for all those opamps ;-). There are now so many of those that it is really hard to make a choice.

That design reminds me of some power amps (well headphone power) from the sixties. But it should work, I do not see what is 'wrong' with it technically. Those things (audio people) like to use this sort of thing to drive transformers. Now that is a whole different subject, as I got in the seventies a request to design an audio distribution amp, and my view was that you had to terminate cables by their characteristic impedance, but the audio guys did not. But I was driving those transformers with very much a similar circuit. Except for the inductors.

So what part of that circuit is junk?

Sunny, but COLD... it got down to 70°F in the house last night, and a cold wind is blowing today ;-)

Class-B stage for a start. Cruddy bias methods for another.

I'll have to surf, but I think you can buy 0.8nV/rt-Hz off-the-shelf. If not, adding a bipolar front-end to a single-chip OpAmp is a better, easier, cheaper way to go.

...Jim Thompson

Now-a-days, all my OpAmp designs are going into custom ASIC's, not into jelly-bean stuff.

...Jim Thompson

On a sunny day (Wed, 29 Nov 2006 12:04:55 -0700) it happened Jim Thompson wrote in :

Here it is winter with summer temperatures, and the first mammoths are beginning to leave their nests. That is that noise you hear.

So you want class A, or even class D?

Would not do that with those temperatures where you are.

Noise comes free here.

Yea, I am a bit out of touch with audiophile noise specs. Are we 48 or 64 bits now?

Yep. It's 54°F right now, with 17MPH winds.

I'm trying to put up outdoor Christmas decorations in my shirt sleeves... guess I'd better put on a jacket ;-)

I wouldn't know either... all I own is a JVC "home theater system", and I'm going deaf anyway :-(

Though I still can hear distortion, particularly in classical pieces... used to play clarinet, so I know what a woodwind ensemble _should_ sound like ;-)

...Jim Thompson

martin griffith a écrit :

One clicked at random from all the list...

Bwahahahaha! Good one!

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

I thought I had already earned the second ?:-)

...Jim Thompson

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Talking s*it about politics does not qualify you for talking s*it about electronics.

DNA

"Fred Bartoli" wrote in message news:456de33a$0$4237$ snipped-for-privacy@news.free.fr...

What are the chances of that!!!!!!!!????????

Sales Rep.....

Has to roll up his shirt sleeve to take a s*it.

DNA

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Oh, alright then.

Talking s*it about electronics does not qualify you for talking s*it about politics.

However, it seems you might be confusing the issues with rights. Try to stay on subject.

DNA

So he's a _normal_ sales rep ?:-)

...Jim Thompson