John Curl's Blowtorch preamplifier part II

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I just got a full demo card of our AD1955 DAC our ESS 9018 "equivalent". In their infinite wisdom it was laid out to facilitate op-amp rolling :dead:.

In my experiments with AD1955 a few years back I found the LM6172 to sound the best and with the lowest possible feedback capacitance that still sounds OK. I think I ended up with 4.7pF. Trying NE5532 there, with no feedback capacitance is an interesting experience, to say the least :)
 
maybe we're having a translation effect here. An op-amp is a topology, generally its that big a** triangle with + and - inputs. It can be either discrete or integrated. Most of the amps talked about here are op-amps, both integrated and discrete. Remember the original op-amps were tube!

Cheers
Alan
Philbrick k2-w it had 2 12ax7 tubes with an octal base 1952. Have one in grey . :snoopy:
 
Sorry, thin film resistors are as linear as good discretes, sub 5ppm and 17ppm/C TC over a full 20V swing, 25k resistor for something that has countable atoms thickness.
it was a real question. I have not the slightest idea of how ICs are made.
Thanks for the answer.
(sofaspud, I use no translator, only to understand jacco's French ;-)
 
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> Thermal feedback, especially with Class B output stages is a real potential problem.

That's the least problem. On the scale of IC construction,
audio acts like RF to a great extent. Everything bleeds into
every thing else. Most IC's in and out of a circuit give the
effect of a blanket between (and then not) the speakers and ears.

So is a blanket worse than the 'veils' that most audio writers love to talk about? And surely so much HF attenuation would be clearly measurable?
 
Sy,
How about that the interpretation of what is measured is misconstrued? The measurements can be totally accurate but the context of the use of those results can be misapplied. Is that a better way of looking at this than saying that the measurements are not accurate when we know they are? There are no ways to calibrate anyone's hearing as far as I understand it so that you can make comparative analysis from hearing alone between parties. The agreements are only contextual, not scientifically accurate in any real sense.
 
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