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Old 23rd October 2002, 10:27 AM   #11
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Default 5534 vs 711

What function is that NE5534 being used for?

Both chips maybe pin interchangeable, but are quite different beasts. The 5534 is low noise, the 711 is not.

The 5534 is now cheap, but in the past it was not. The 711 was never too expensive, but now it probably costs a bit more. The reason being that now there are several 5534 types, but only Analog makes the 711.

But before wondering whether to force the 5534 into class-A, which will probably warm it a bit, you should wonder if it's up to the task proper to a modern chip in your application.



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Old 23rd October 2002, 03:56 PM   #12
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Like OPA637 for phonoamps.
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Old 23rd October 2002, 06:31 PM   #13
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Quote:
Originally posted by The Saint
Putting an Opamp into class A with a resistor on the o/p to any supply rail was originally shown by Walt Jung of Audio Amateur Magazine fame.
An active current source works great as well.
The concept works and it does make an improvement...
This technique predates Walt Jung. Barry Thornton was using
resistors about 1970, and the Forte preamp (Pass) used
current sources in the early 80's.
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Old 23rd October 2002, 07:49 PM   #14
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Default Re: 5534 vs 711

Quote:
Originally posted by carlmart
But before wondering whether to force the 5534 into class-A, which will probably warm it a bit, you should wonder if it's up to the task proper to a modern chip in your application.
DrewP, what are you going to use this NE5534 for?

I agree with carlmart, look for a modern chip instead.

OPA134 is a good NE5534 replacement and also not so expensive.
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Old 23rd October 2002, 07:51 PM   #15
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Quote:
Originally posted by Nelson Pass


This technique predates Walt Jung. Barry Thornton was using
resistors about 1970, and the Forte preamp (Pass) used
current sources in the early 80's.
Yep....Good 'ol Quintessence .... Do you know whatever happened to Barry ? ..... Mike (who used to work there)
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Old 23rd October 2002, 07:51 PM   #16
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Nelson, or somebody else: How much improvement do I get with this class A thing, together with a modern chip? Any audiable/measureable difference at all?
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Old 23rd October 2002, 08:03 PM   #17
mlloyd1 is offline mlloyd1  United States
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Default Re: NE/SE5534 vs AD711

Calmart asks a (the?) very important question.

Another beneficial characteristic of the xx5534 type parts (vs. the AD711) is a beefier output stage. I've used the AD711 for a long time and after listening to it years ago in some of my prototype circuits, I wouldn't use it in line driver applications without a buffer. It's better than the TL07x stuff in this regard, but not by a whole lot. Nowadays, I like the AD711 in DC Servo applications, power supply regulators, music sythesizer modules (oops, that one slipped out), etc....

The AD711 is a pretty good GENERAL PURPOSE BiFET op amp, not among the best choices for high perfrmance audio line amps, IMHO .

Quote:
Originally posted by carlmart
What function is that NE5534 being used for? ....
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Old 23rd October 2002, 08:25 PM   #18
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Last I heard Barry Thornton was in Arizona, possibly rep-ing
electronics.
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Old 23rd October 2002, 08:27 PM   #19
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Quote:
Originally posted by peranders
How much improvement do I get with this class A thing, together with a modern chip? Any audiable/measureable difference at all?
Marginal difference at best, but still a cute tweak that
anyone can do.
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Old 23rd October 2002, 08:35 PM   #20
BrianGT is offline BrianGT  United States
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Quote:
Originally posted by jean-paul
Like OPA637 for phonoamps.
I have a bunch of opa627 and opa637 that a friend gave me (20 of each). Can I use these in place of opa2134 (assuming that I modify the wiring to use two single opamps instead of one double) in my active crossover? Are these opamps much better in terms of sound quality over the opa2134?

I read over the datasheets, but I couldn't find the difference in the two (627 and 637). Anyone know?

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