Discrete Op Amps For Amplifying Audio Signals

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#1
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At US$59.99 for the cheapest one, they would want to be "nice"!

Ross McKenzie ValuSoft Melbourne Australia

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Bob Widlar would be pissing himself methinks. Why did they put back to back schottky diodes across the inputs? Noisy as hell as well as being leaky. But the whole thing is snake oil.

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Yeah. Probably aimed at the oxygen-free copper leads crowd.

 

Ross McKenzie ValuSoft Melbourne Australia

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Kartman wrote:
Why did they put back to back schottky diodes across the inputs?

 

Don't see them, but not doubting you either.

 

At $60.00usd thats pretty steep.  I can use a pair of NE5532's to get the same gain for a lot less.

 

They are looking for folks to review the gear....hhhmmmmmmm....Might have to fill out a questionnaire.

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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jgmdesign wrote:
They are looking for folks to review the gear....hhhmmmmmmm....Might have to fill out a questionnaire.
Remember to practice safe reviewing. Wash your hands frequently and don't get too close to the subject. cheeky

Ross McKenzie ValuSoft Melbourne Australia

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Jim, but you won't get the same 'clarity' and 'soundstage'! I really doesn't make sense to me to shove in op-amp replacements and get a half-arsed solution vs just doing the pre-amp stages in class A like the olden days.

 

I got an abject lesson on PSRR the other day whilst fixing a guitar amplifier - the thing would oscillate at 6kHz at power. Turns out the 47uF caps on the op-amp power rails were shot.

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Oooooo!  Those will go really well with my new speaker cables...

"Experience is what enables you to recognise a mistake the second time you make it."

"Good judgement comes from experience.  Experience comes from bad judgement."

"Wisdom is always wont to arrive late, and to be a little approximate on first possession."

"When you hear hoofbeats, think horses, not unicorns."

"Fast.  Cheap.  Good.  Pick two."

"We see a lot of arses on handlebars around here." - [J Ekdahl]

 

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Ha!

 

Look at the price of their USB cables!  Of course the silver/whatever conductors make a BIG difference to the fidelity of the digital signals.

I wonder if anyone makes 'audiophile' valves with precious metal innards?

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The advert talks about "2 pole compensation". What I learned, waaaay back in the Pleistocene (or so it now seems) as that 2 poles are a recipe for instability.

 

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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jgmdesign wrote:

Kartman wrote:
Why did they put back to back schottky diodes across the inputs?

I can use a pair of NE5532's to get the same gain for a lot less.

 

Interesting fact - the 5532 and 5534 have a pair of diodes strapped across the input pins. Over-current those and you are sure to kill the chip.

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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I'm not disputing the diodes as such, but the particular type of diode they chose - Schottky.

 

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Kartman wrote:

I'm not disputing the diodes as such, but the particular type of diode they chose - Schottky.

 

If it's a parallel inverse pair, to clamp any differential input voltages, then Schottkies have a lower forward voltage than ordinary Silicon.

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

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joeymorin wrote:

Oooooo!  Those will go really well with my new speaker cables...

Thats funny.

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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Kartman wrote:
Jim, but you won't get the same 'clarity' and 'soundstage'! I really doesn't make sense to me to shove in op-amp replacements and get a half-arsed solution vs just doing the pre-amp stages in class A like the olden days.

Not arguing.  My point was that they were looking for reviewers.  Why not let them send me a few and compare them? 

 

JIm

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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ka7ehk wrote:
The advert talks about "2 pole compensation".

I read that as their compensation scheme introduces 2 extra poles. Perhaps that makes a faster amplifier than introducing a single dominant pole.

 

I expected to read about astonishingly low levels of distortion but couldn't find that. Perhaps the distortion levels are astonishingly high.