John Curl's Blowtorch preamplifier

[PMA]

Syn, Jan: Why do not you show your design invention in a single stage, extremely low noise, low distortion, fast and wideband circuit? Anyone can take 110dB FB and show great LF specs in a slow circuit.

[jan.didden]

Originally posted by chascode
OT Jan, I enjoyed your interview of Eduardo de Lima in the new "Voice Coil".

Best, Chuck Hansen

/OT
Chuck, thank you. I've just done a lengthy one with Erno Borbely, I'm sure you'll like that as well.

Jan Didden

[john curl]

Now, we separate the 'men' from the 'boys' . Any other 'comments' from the critics gallery?

[jan.didden]

Originally posted by PMA
Syn, Jan: Why do not you show your design invention in a single stage, extremely low noise, low distortion, fast and wideband circuit? [snip]

Pavel, I don't have one. That's why I ask about that circuit, I want to learn. Is that a problem?

Jan Didden

[john curl]

Just add an IC to this stage, feedback to the emitters. It is easy!
'Old John' I like that, thanks PMA!

[john curl]

Where is everybody?

[syn08]

Originally posted by PMA
There is a feedback and feedback. This has nothing to do with conventional dominant-pole VFB design. 57dB and 1.7MHz BW, no slew rate limitation. This counts.

We care how it sounds, not only how it measures THD in audio band.

"there is feedback and feedback" - that's the second best joke I've heard lately. The first is the Robert Heinlein quote: “Never try to teach a pig to sing; it wastes your time and it annoys the pig.”

And of course, when anything else fails, join the golden ear brigade team.

Wanna a circuit that has over 120dB OL gain, 100MHz unity gain OL bandwidth and is unconditionally stable for resistive loads? Take a look at the attachment. Now, try to figure out how it works, and what would it take to allow capactive loads (and hence make it useful for driving a power stage). Hint: you may still get over 120dB gain in the audio band, while limiting the BW at around 2 MHz.

Of course, this circuit sounds like crap It's built out of dirty sand and uses that "other" NFB that you dislike.

[john curl]

But, how quiet is it? NOISE is EVERYTHING with MC input.

[Steve Eddy]

Originally posted by PMA
We care how it sounds, not only how it measures THD in audio band.

Yet to hear some talk, there's really no meaningful distinction between the two, and it ultimately just boils down to a numbers game.

se

[john curl]

Isn't anyone going to ask a useful question?