Paul Wolff opamp designs

[Family Hoof]

Albiet in very general terms, Paul Wolff gives a nice little talk about designing his new opamps on the Tonelux website. Just stumbled upon this today and thought it might be of interest to some of you.

 

[chrissugar]

Interesting article.
It looks like a new trend to not include the output buffer in the global feedback loop. The same thing in the recent Borbely article. Curious about the topology of the buffer, just four transistors. Probably a simplified Jung buffer?
In the old Walt Jung article the buffer is inside the feedback loop.

chrissugar

 

[Peter Simonsen]

[quote author="chrissugar"]Interesting article.
It looks like a new trend to not include the output buffer in the global feedback loop. The same thing in the recent Borbely article.
chrissugar[/quote]

ohh yes,

most people are slow !!! * :green:

Kind regards

Peter

 

[featherpillow]

Curious about the topology of the buffer, just four transistors

Me too! I guessed a simple push-pull stage w/followers. Funny, I breadboarded something like that yesterday, except I used a FET input stage in front of it.

Class AAB? Isn't that just AB2?

*edit* I just realized something--it's probably just a simple current amplifier, like this one!

 

[featherpillow]

I just noticed something--the description of the EQ module on the website reads:

The EQ4P is a DISCRETE Parametric Equalizer

But when you look at the image of the PCB, it's filled with IC's...?

Am I missing something?

 

[Samuel Groner]

But look at all those resistors and caps. These are all discrete parts, no? :grin:

At least there is one discrete opamp in there...

Samuel

 

[featherpillow]

These are all discrete parts, no?

Ha ha! That's true...

I thought I remembered reading somewhere that a discrete parametric EQ was impossible to build. You can't get a discrete circuit to behave like a GIC. (not counting discrete opamps)

 

[fum]

They probably mean their not going to tell you about it. How's that for discrete? :grin:

ju

 

[featherpillow]

That would be a "discreet" EQ. :wink:

 

[bcarso]

Which, if noisy, might hiss, but never tell...