"The NE5532 outperforms..." really?

[Transmogrifox]

"The NE5532 outperforms the OP275"  is a quote I read in a different thread as a response to one of my posts.  I thought, "Wow! If it's true, that op amp sure is a lot less expensive than the OP275"

...so I looked up the datasheet and compared the 2.

OP275 bandwidth is around 15 MHz if I remember right, NE5532 at 140 kHz.  

That's the only parameter where the NE5532 outperforms the OP275.

OP275 Noise figure is about 14 nV/rtHz
NE5532                            --8nV/rtHz

neither here nor there, both are pretty good, so the statement still holds.

Now, slew rate--OP275 blows the NE5532 out of the water with a 22 V/us, where the NE55432 is at 8 V/us.

The NE5532, being a BJT opamp suffers from low input impedance, again the OP275 having JFET inputs has very high input impedance regardless of the closed-loop gain.

The fact that the NE5532 data sheet doesn't even list THD means that it's not specifically and designed for low THD.

The OP275 is on the order of 0.006% THD+N.  That's very pristine audio quality.

The moral of the story is that we can't make statements like this without being more specific.  If you want better noise performance (like for a buffer), us an NE5532...if you're making filters, you need the high input impedance and high slew rate of the OP275.

The bandwidth on the NE5532 doesn't mean anything for guitar circuits since the output signal is generally large enough amplitude that the slew rate limits the frequency response long before the limited bandwidth does.  

5 MHz bandwidth is more than enough for most audio circuits.

[petemoore]

I don't know if you can infer that this means anything but, I still havethat 5532 sitting on the bench, the only thing I think I have one in now is the OS Comp, but I'm using Dyna these days for comp.
 I put it in circuits, many OD's etc. 4558's seem to end up in them. I can't say I've had alot of luck applying the NE5532's to circuits I like.
 I still need to A/b the OPA275 in the OS. It still 'Gak's' a bit with my Dimarzio HB honkin' on it using the NE5532, I triedthe 4558 in it, preferring the 5532 there...so far...

[jrc4558]

BJT input for brown sound, J-fet input for filters, non-tone-coloring boosters and such. I guess that's enogh for sommon DIYer like me.
Thanx for the discourse though. I like reading educated people's analysises.

[MartyMart]

Interesting, I've used the "single" NE5534ap version in my tube reamers with great success and have tried an NE5532ap in a Boss SD-1, but for some reason I preferred either a 4558/9 or OPA2134 in those.

I have quite a few NE5532's from an old "Phillips CDi " player and some from a dead "Peavey SX" sampler front end, perhaps they are better for that kind of "HiFi" use, filtering/digital recording etc ?

Are those levels of specs relevant to an "overdrive"  !!

Marty.

[Phorhas]

I recently fell in love with the LM833 - it's a little super OA and sound really good in a TS-like Fx - and is also awsome with no diode in the FBL at all!

[Torchy]

crp

[Paul Marossy]

Maybe the person mentioned in that thread read this page?! (From Doug Self's "Amplifier Institute") http://www.dself.dsl.pipex.com/ampins/webbop/op275.htm

Here's what Doug Self has to say about the NE5532 opamp:
http://www.dself.dsl.pipex.com/ampins/webbop/5532.htm

Judge for yourself. I personally think that the OP275 is a great opamp.  

[WGTP]

The hard part with spec.s and distortions is knowing which ones are related to sounding good.  The 4558 is favored by many and has some of the worst spec.s.  It's a matter of APPLICATION, OPINION and PREFERENCE.  

[Paul Marossy]

It's a matter of APPLICATION, OPINION and PREFERENCE.

Yep.  

[R.G.]

Lemme ask ya'll a hypothetical question.

Is a thoroughbred race horse of the finest breeding and training better than a Clydesdale (think of Budweiser beer wagon) draft horse?

[Torchy]

crp

[David]

Lemme ask ya'll a hypothetical question.

Is a thoroughbred race horse of the finest breeding and training better than a Clydesdale (think of Budweiser beer wagon) draft horse?

I've been looking at bad code all day and the jet lag is hitting big time, so I'm feeling cranky.  I'll bite.  This is a purely subjective question which cannot be answered usefully without providing more information first.  The race horse would slaughter the Clydesdale in a race.  However, subject the two to a pulling contest, and I'll put my money on the Clydesdale every time.

By extension, the question "is op-amp X better than op-amps A thru W" is not valid until the operational framework is provided.

How did I do, oh august one?

[RDV]

I inherited a Mackie 1202 mixing board in pieces. I put the pieces back together and traced the problem in the circuit to a dual OA that drove the main output. It was an SMD part, and I happened to have one. An OP275. It's now fixed. All that drivel about specs that dogs can't even hear affects me not.

RDV

[R.G.]

How did I do, oh august one?

You are wise beyond your years, Grasshopper.

[David]

How did I do, oh august one?

You are wise beyond your years, Grasshopper.

Cranky middle-aged American software geek in Warsaw takes deep bow, smiles, and strains back.
:lol:

[petemoore]

Well there you have it.
 That dredged up some valueable info.
 I'm thinking now what I typed IS drivel...and that my chip I test 'n retest in cct.s is just damaged or something...quite possible.

[Transmogrifox]

I like your responses.  Thanks all.  

I agree that this becomes very subjective when applied to stompboxes.  Sometimes a higher noise, higher distortion IC sounds sweeter, for instance, the RC4458 measures a little lower than both on the specs, but many people's ears tell them it sounds sweet in a TS type circuit.

Definitely use your ears.

[WGTP]

Horses are the product of thousands of years of genetic engineering by humans and are designed for different purposes (not unlike Op Amps).  The Thorobreds were produced when some dude brought 3 Arabian Stallions (warm blooded) back to England and started crossing them with the cool blooded European stock (Clydesdales, etc).

Although the best Thorobreds are subject to the highest level of engineering of any animal, because of the $$$, Clydesdales are probably not far behind.  I understand Bud has a pretty good breeding program.

For distortions, I would go with the Drag Racers of the Horse world, the American Quarter Horse, although Arabians might be more mysterious sounding, and Zebra's???

I didn't make this up, but I'm not sure about the details.  

[Mark Hammer]

Hope to goodness it wasn't me making such a claim about the chips in question.

The "slew thing" is truly misunderstood in this community.  Again, I'm not the expert EE here, but the relevance of the slew figure depends on the application, as is noted by many.  It is really, REALLY, hard for me to think of a context in which a slew rate of 8v/us would be critical to the functioning of an analog floor pedal, and really, REALLY, REALLY hard for me to imagine an instance where 22v/us would hold any audible advantage over 8v in the same category of applications.

The slew rate depicts how capable the device is of producing large scale voltage swings with great rapidity.  If you were looking for a 741 to be able to accurately reproduce 18khz waveforms while applying a gain of 200 at the same time, it ain't gonna happen.  Now if you asked it to reproduce the same waveform with a gain of 5, NOW we're talking, since a gain of 5 might imply a simple change between an input signal of 30mv and and output of 150mv.  Clearly the slew requirements aren't all the stringent.  As I noted in another thread, it is a common trick to distribute the gain of a circuit amongst several devices, such that the amount of voltage change each is tasked with is actually modest.  So, a trio of 741's each with a gain of 5 would yield a combined gain of 125, with none of them being asked to produce a particularly huge voltage swing.  Where more modern devices provide advantage is that all the required gain can be packed into a single device without having to pay a functional cost in terms of usable bandwidth

Typically, the occasions where required speed of voltage swing starts to become demanding in floor pedals is in, you guessed it, distortion units.  As it turns out, fortunately, thse things sound like crap when the bandwidth is too wide, so they tend to have a fairly restricted bandwidth.  This means that while the device might have to swing wide in terms of voltage, it won't be obliged to do so very quickly, making even a limited slew rate more than acceptable.

Now, if we were talking about a phono cartridge preamp in a high end system that is expected to deliver 40db or more of gain for a puny mag cartridge (or worse, moving coil) with at least 25khz bandwidth or more, slew rate WILL start to matter.  It is important to recognize when concepts imported from the audiophile literature are, and are not, pertinent.

In case it matters, though, buddy of mine makes some mic preamps with OP-275's and apparently they are absolutely killer.

[brett]

5 MHz bandwidth is more than enough for most audio circuits.

?? 5 MHz bandwidth ??  Come-on!  :lol:

Ok, so you meant 5 MHz gain-bandwidth product.  So that means in a Tubescreamer, with maximum gain of 117, the gain extens to 43kHz.  That's at least twice as high as a child with perfect hearing can hear, and about 4 times higher (or a full 2 octaves) above what I (and probably you) can hear.

Let's face it - these op-amps are all mind-bogglingly good.  The numbers (volts per microsecond, MHz) are for the geeks to play with (ie. the "mine's bigger/better than yours" games).

Except for the slight waterfall effect in the background, even the old RC4558 stands up ok.

Did we need to have this discussion again (for the how manyth time)??

cheers