EMRFD Message Archive 1604
Message Date From Subject 1604 2008-04-26 23:05:05 Rick Op-Amps in EMRFD I can't speak for Wes and Bob, but all of my circuits in chapters 8, 9 and 12 and the few
scattered throughout the other chapters use NE5532 op amps. I design many signal
processing circuits, and my usual requirements are low noise, high output drive capability,
and very low distortion. The NE5532 nicely fits those requirements for many of my
applications. I used them in all of the circuits I described in EMRFD.
I built a receiver nearly 20 years ago using some available LM324 op-amps and quickly
discovered the output circuit issue, which is well documented in the literature. I added
current sink resistors to fix the problem in that particular circuit, and then did a search to
find a better generic op-amp to use in my projects. I have been keeping NE5532 dual op-
amps on hand ever since for use in my prototype designs and experiments.
Data sheets are available on the web for most common op-amps, and they are written to
be read by all of us who use op-amps. A few hours studying different op-amp data
sheets is very helpful in understanding the differences and similarities.
The differences can be major, and the NE5532 would be a very poor choice for some
common op-amp applications.
After I have a working prototype that I can measure, I sometimes experiment with
different parts from the excellent offerings from Analog Devices, Linear Technology,
National Semiconductor and several other companies that have continued to push the
performance envelope for op-amps.
The NE5532 was a good choice for my low-noise analog signal processing circuit designs
nearly 20 years ago. Perhaps I would choose a different generic op amp if I were to select
one today, but it has become one of my familiar and trusted components, along with the
2N3904, 2N3906, 1N4148, and J310.
1606 2008-04-27 10:03:15 Frank Re: Op-Amps in EMRFD Any chance there's a quad version of the '5532? I'm facing some tight
I've pored over op amp literature for days....this is my first time
using op amps for audio. In the past, I've rolled my own diff amps
and complementary driver stages as I've needed circuits, and have used
op amps mainly as parts in DC power supplies and biasing. The
previously-mentioned MC3403, interestingly enough, claims specifically
to not have crossover distortion, but "no crossover distortion" seems
not to be a parametric element referenced in any selection guides.
I rather expect those who've used op amps at audio for years have
understood the issue for so long that it's passe; indeed, an internet
search of "op amp crossover distortion" yields surprisingly few hits
on the topic, most of them suggesting how the silicon designer avoids
the issue - not the end user.
So, I'll get some of the 3403s
1607 2008-04-27 11:13:13 Wes Hayward Re: Op-Amps in EMRFD Hi all,
The op-amp thing is interesting and one of those things that is
especially dramatic when we discover it for ourselves. The LM-324
and similar parts, usually derivatives, really are rather poor for
audio applications. The little glitch that occurs when the part
runs out of drive capability is small enough that you have to look
carefully for it when first examining a 'scope trace. But you can
sure hear it. Once looking with a little bit of care, it shows up
with ease on a 'scope. It is instructive to listen and watch at
the same time.
I recently discovered some similar distortion in the audio output
amplifier in a receiver. I ended up replacing the current hog
follower output that is in the upper right corner of Fig 6.78 with
one of Rick's designs. See Fig 9.47. The new circuit is extremely
I took a look at Fig 3.58 (a poor number choice!) and noted that I
had been specific about the op-amp type in the caption. I then went
looking in my junk, but alas, could not find the board. It is
around somewhere. We really did build it. I suspect that I used
1458s for that model, for that was a favorite at the time. The 1458
is just a dual 741. I never noticed the glitch with that
amplifier. That example ran from a 12 volt supply and was always
running with pretty low output.
I'm with Rick -- I really like the 5532 as a general purpose op-amp.
I keep some in stock (I even know where they reside in the the junk)
in both DIP and SOIC-8 packages. The noise is pretty good, although
not as good as things like the OPA-27. The OPA-350 series is low
noise and a great general purpose part although I don't have much
direct experience with it. Both of these feature lower noise than
the 5532, but not by a lot.
At one time we treated the 5534 as a quad that was otherwise
identical to the 5532, a dual. I don't think that this is the case
though. Also, I have seen comments about variations in the 5532
depending on the manufacturer. After I first saw this, I checked my
stock and the DIP versions I have are all older Signetics parts.
There is a comment at the very end of the RC Active low pass section
on page 3.25 where the distorti
1609 2008-04-27 16:18:53 michael taylor Re: Op-Amps in EMRFD > At one time we treated the 5534 as a quad that was otherwiseThe (TI) NE5534 is a single op-amp version in an 8-pin package, of the
NE5532 dual op-amp. Both are available for ~$1 in single quantities,
so they should be both cheap enough to encourage experimentation with
(rather than using the "classic" 741 and MC1458 / LM747),
1614 2008-04-28 07:05:23 ehydra Re: Op-Amps in EMRFD They cost Euro 0,20 in Germany. I think that is approx. $0,30.
michael taylor schrieb:
>> At one time we treated the 5534 as a quad that was otherwise
> The (TI) NE5534 is a single op-amp version in an 8-pin package, of the
> NE5532 dual op-amp. Both are available for ~$1 in single quantities,
> so they should be both cheap enough to encourage experimentation with
> (rather than using the "classic" 741 and MC1458 / LM747),
> -Michael, VE3TIX
> Yahoo! Groups Links
1624 2008-04-29 17:52:25 jr_dakota Re: Op-Amps in EMRFD