John Curl's Blowtorch preamplifier part II

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#74,626
Esperado said:
Yes. Low noise, slew rate large enough if we follow the usual criterias, and enough current to drive any 600 Ohms loads. The price was high enough to give them some prestige and low enough for anybody could afford them...
I still have some samples of the original production.
Click to expand...
And a reasonable tradeoff of voltage noise and current noise, in the early days of biFET op amps, which have the additional disadvantages of voltage-variable input-to-substrate capacitance and high voltage noise. All of these problems have been addressed in modern parts, but many still choose between TL072 and BA4560 for gummint work. I was talking to a friend the other day and his eyes got wide when I mentioned op amps that run a couple bucks in thousands.
 
#74,627
Just purchased a new ASUS -118db sound card.


They come stock with 5532's , Asus rates the specs with them .
Then they offer up all sorts of subjectively based "upgrade kits"


-an example on one of their outboard sound cards.
https://www.asus.com/Essence-Hi-Fi-Audio/Xonar_Essence_One_Plus_Edition/

Halfway down the page is the "mumbo-jumbo" regarding
SQ. Perhaps interaction with DAC Z (or just magic).😀

"MUSES02" op-amp ... that's new !
MUSES Official Website
The OPA's .. just about any 8 pin critter.

Amazing these come with the 5532 stock.

OS
 
#74,628
The TDA1024 (Phillips) or NE5534 (Signetics, [then owned by Phillips]) was designed primarily for audio use. And they had feedback from Studer, and other audio manufacturers on the problems with the then (early 70's) IC alternatives.
However, the NE5534, although it meets a number of measured guidelines, like voltage swing, current output, slew rate, (even noise), and closed loop linearity, it DOESN'T replace high quality discrete modules without compromise. That is the problem: WHY?
Now, some of us with real 'hi end' experience like Richard Marsh and Esperato, know this to be true. Others, with less experience in 'hi end' audio like Grado or Magnepan users almost exclusively, will not appreciate the problem. That is your problem, not ours, so please let us try to find an ADEQUATE REPLACEMENT for the NE5532-34 through the combined subjective experience of a number of audiophiles. This means OPEN LISTENING, not A-B double-blind tests.
For example, what about the AD275? How about the AD825, LME4562? etc, etc.
 
#74,630
RNMarsh said:
As some recall, I bought a used Mastering recorder a few months ago. When I played music thru it, it sounded dull, lifeless. I opened it up to see if I could mod it in some way but gave up and didnt do anything. It used mostly 5532/4 opamps for analog processing.

That was first time I heard a product with those opamps. Gnerally, I go with descretes for audio.

That someone thinks it is fine is not relevent to Me. And, does not change my perception of what I hear. Once again we have data from other people that is perceived same way. That is part of the meta-data I refer to. There are a significant number of people who hear this or that exactly the same way.
[note that significant does not have to be the majority]

The 5532/4 resembles 'compressive' behaviour which results in life-less sound quality.



THx-RNMarsh
Click to expand...
I agree that the 5534 can sound 'polite'.
Take a look on Pro-Audio forums for subjective evaluations of stereo opamps.

I built a jig pcb with ideal power, ground and signal routing and decoupling for the purpose of critical listening to opamps.
I need to buy some more modern opamps to extend the range of types on test, but my conclusion was that there are readily audible differences in a single stage line level buffer stage.

Dan.
 
#74,638
No, SY, as most preamps have to operate with up to 50K input source resistance, yet should have Voltage noise less than 5nV/rt Hz. This excludes some IC's that have even lower voltage noise, but have higher current noise.
There are a large number of single and dual IC's that fill the requirements, BUT which ones sound best? Right now, I need a really great replacement for the NE5532. Looking at ADE parts, I did not find the perfect replacement. Am I missing some IC from AD, and what about all the other manufacturers?
 
#74,640
SY ---- yes. It most definitely does. Which could explain also why some random opamp swapping results in better or worse or optimum performance. Over in the test equipment section...... I replaced the HP 339A oscillator opamp from a Harris (2525?) to various and found only one that would get me lower distortion with the Given circuit Z values.

THx-RNMarsh
 
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